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Sample records for ise system development

  1. ISE System Development Methodology Manual

    Energy Technology Data Exchange (ETDEWEB)

    Hayhoe, G.F.

    1992-02-17

    The Information Systems Engineering (ISE) System Development Methodology Manual (SDM) is a framework of life cycle management guidelines that provide ISE personnel with direction, organization, consistency, and improved communication when developing and maintaining systems. These guide-lines were designed to allow ISE to build and deliver Total Quality products, and to meet the goals and requirements of the US Department of Energy (DOE), Westinghouse Savannah River Company, and Westinghouse Electric Corporation.

  2. Microcanonical simulation of Ising systems

    International Nuclear Information System (INIS)

    Bhanot, G.; Neuberger, H.

    1984-01-01

    Numerical simulations of the microcanonical ensemble for Ising systems are described. We explain how to write very fast algorithms for such simulations, relate correlations measured in the microcanonical ensemble to those in the canonical ensemble and discuss criteria for convergence and ergodicity. (orig.)

  3. Dynamics of asymmetric kinetic Ising systems revisited

    International Nuclear Information System (INIS)

    Huang, Haiping; Kabashima, Yoshiyuki

    2014-01-01

    The dynamics of an asymmetric kinetic Ising model is studied. Two schemes for improving the existing mean-field description are proposed. In the first scheme, we derive the formulas for instantaneous magnetization, equal-time correlation, and time-delayed correlation, considering the correlation between different local fields. To derive the time-delayed correlation, we emphasize that the small-correlation assumption adopted in previous work (Mézard and Sakellariou, 2011 J. Stat. Mech. L07001) is in fact not required. To confirm the prediction efficiency of our method, we perform extensive simulations on single instances with either temporally constant external driving fields or sinusoidal external fields. In the second scheme, we develop an improved mean-field theory for instantaneous magnetization prediction utilizing the notion of the cavity system in conjunction with a perturbative expansion approach. Its efficiency is numerically confirmed by comparison with the existing mean-field theory when partially asymmetric couplings are present. (paper)

  4. ISEE (InformationsSystem Erneuerbare Energie): Renewable Energy Information System

    International Nuclear Information System (INIS)

    Grebe, R.; Koch, H.

    1991-01-01

    Since the end of 1989 ISET has been operating the title database ISEE. Access to this on-line database may be obtained by any interested party posessing a computer, which is connected to the network of the 'Deutsche TeleCom' by telephone or Datex-P. The command language of ISEE is German. ISET will establish an English version in 1991/1992. In brief attention is paid to the components of the ISEE database, its user groups, the possibilities to access ISEE, and further developments. 3 figs

  5. Real-time ISEE data system

    Science.gov (United States)

    Tsurutani, B. T.; Baker, D. N.

    1979-01-01

    A real-time ISEE data system directed toward predicting geomagnetic substorms and storms is discussed. Such a system may allow up to 60+ minutes advance warning of magnetospheric substorms and up to 30 minute warnings of geomagnetic storms (and other disturbances) induced by high-speed streams and solar flares. The proposed system utilizes existing capabilities of several agencies (NASA, NOAA, USAF), and thereby minimizes costs. This same concept may be applicable to data from other spacecraft, and other NASA centers; thus, each individual experimenter can receive quick-look data in real time at his or her base institution.

  6. Real-time ISEE data system

    International Nuclear Information System (INIS)

    Tsurutani, B.T.; Baker, D.N.

    1979-01-01

    Prediction of geomagnetic substorms and storms would be of great scientific and commercial interest. A real-time ISEE data system directed toward this purpose is discussed in detail. Such a system may allow up to 60+ minutes advance warning of magnetospheric substorms and up to 30 minute warnings of geomagnetic storms (and other disturbances) induced by high-speed streams and solar flares. The proposed system utilizes existing capabilities of several agencies (NASA, NOAA, USAF), and thereby minimizes costs. This same concept may be applicable to data from other spacecraft, and other NASA centers; thus, each individual experimenter can receive quick-look data in real time at his or her base institution. 6 figures, 1 table

  7. Effective-field renormalization-group method for Ising systems

    Science.gov (United States)

    Fittipaldi, I. P.; De Albuquerque, D. F.

    1992-02-01

    A new applicable effective-field renormalization-group (ERFG) scheme for computing critical properties of Ising spins systems is proposed and used to study the phase diagrams of a quenched bond-mixed spin Ising model on square and Kagomé lattices. The present EFRG approach yields results which improves substantially on those obtained from standard mean-field renormalization-group (MFRG) method. In particular, it is shown that the EFRG scheme correctly distinguishes the geometry of the lattice structure even when working with the smallest possible clusters, namely N'=1 and N=2.

  8. Diagonalization of replicated transfer matrices for disordered Ising spin systems

    International Nuclear Information System (INIS)

    Nikoletopoulos, T; Coolen, A C C

    2004-01-01

    We present an alternative procedure for solving the eigenvalue problem of replicated transfer matrices describing disordered spin systems with (random) 1D nearest neighbour bonds and/or random fields, possibly in combination with (random) long range bonds. Our method is based on transforming the original eigenvalue problem for a 2 n x 2 n matrix (where n → 0) into an eigenvalue problem for integral operators. We first develop our formalism for the Ising chain with random bonds and fields, where we recover known results. We then apply our methods to models of spins which interact simultaneously via a one-dimensional ring and via more complex long-range connectivity structures, e.g., (1 + ∞)-dimensional neural networks and 'small-world' magnets. Numerical simulations confirm our predictions satisfactorily

  9. A simple approximation method for dilute Ising systems

    International Nuclear Information System (INIS)

    Saber, M.

    1996-10-01

    We describe a simple approximate method to analyze dilute Ising systems. The method takes into consideration the fluctuations of the effective field, and is based on a probability distribution of random variables which correctly accounts for all the single site kinematic relations. It is shown that the simplest approximation gives satisfactory results when compared with other methods. (author). 12 refs, 2 tabs

  10. Ising game: Nonequilibrium steady states of resource-allocation systems

    Science.gov (United States)

    Xin, C.; Yang, G.; Huang, J. P.

    2017-04-01

    Resource-allocation systems are ubiquitous in the human society. But how external fields affect the state of such systems remains poorly explored due to the lack of a suitable model. Because the behavior of spins pursuing energy minimization required by physical laws is similar to that of humans chasing payoff maximization studied in game theory, here we combine the Ising model with the market-directed resource-allocation game, yielding an Ising game. Based on the Ising game, we show theoretical, simulative and experimental evidences for a formula, which offers a clear expression of nonequilibrium steady states (NESSs). Interestingly, the formula also reveals a convertible relationship between the external field (exogenous factor) and resource ratio (endogenous factor), and a class of saturation as the external field exceeds certain limits. This work suggests that the Ising game could be a suitable model for studying external-field effects on resource-allocation systems, and it could provide guidance both for seeking more relations between NESSs and equilibrium states and for regulating human systems by choosing NESSs appropriately.

  11. Volatility behavior of visibility graph EMD financial time series from Ising interacting system

    Science.gov (United States)

    Zhang, Bo; Wang, Jun; Fang, Wen

    2015-08-01

    A financial market dynamics model is developed and investigated by stochastic Ising system, where the Ising model is the most popular ferromagnetic model in statistical physics systems. Applying two graph based analysis and multiscale entropy method, we investigate and compare the statistical volatility behavior of return time series and the corresponding IMF series derived from the empirical mode decomposition (EMD) method. And the real stock market indices are considered to be comparatively studied with the simulation data of the proposed model. Further, we find that the degree distribution of visibility graph for the simulation series has the power law tails, and the assortative network exhibits the mixing pattern property. All these features are in agreement with the real market data, the research confirms that the financial model established by the Ising system is reasonable.

  12. Fluctuation behaviors of financial time series by a stochastic Ising system on a Sierpinski carpet lattice

    Science.gov (United States)

    Fang, Wen; Wang, Jun

    2013-09-01

    We develop a financial market model using an Ising spin system on a Sierpinski carpet lattice that breaks the equal status of each spin. To study the fluctuation behavior of the financial model, we present numerical research based on Monte Carlo simulation in conjunction with the statistical analysis and multifractal analysis of the financial time series. We extract the multifractal spectra by selecting various lattice size values of the Sierpinski carpet, and the inverse temperature of the Ising dynamic system. We also investigate the statistical fluctuation behavior, the time-varying volatility clustering, and the multifractality of returns for the indices SSE, SZSE, DJIA, IXIC, S&P500, HSI, N225, and for the simulation data derived from the Ising model on the Sierpinski carpet lattice. A numerical study of the model’s dynamical properties reveals that this financial model reproduces important features of the empirical data.

  13. Effective field renormalization group approach for Ising lattice spin systems

    Science.gov (United States)

    Fittipaldi, Ivon P.

    1994-03-01

    A new applicable real-space renormalization group framework (EFRG) for computing the critical properties of Ising lattice spin systems is presented. The method, which follows up the same strategy of the mean-field renormalization group scheme (MFRG), is based on rigorous Ising spin identities and utilizes a convenient differential operator expansion technique. Within this scheme, in contrast with the usual mean-field type of equation of state, all the relevant self-spin correlations are taken exactly into account. The results for the critical coupling and the critical exponent v, for the correlation length, are very satisfactory and it is shown that this technique leads to rather accurate results which represent a remarkable improvement on those obtained from the standard MFRG method. In particular, it is shown that the present EFRG approach correctly distinguishes the geometry of the lattice structure even when employing its simplest size-cluster version. Owing to its simplicity we also comment on the wide applicability of the present method to problems in crystalline and disordered Ising spin systems.

  14. Computer networks ISE a systems approach

    CERN Document Server

    Peterson, Larry L

    2007-01-01

    Computer Networks, 4E is the only introductory computer networking book written by authors who have had first-hand experience with many of the protocols discussed in the book, who have actually designed some of them as well, and who are still actively designing the computer networks today. This newly revised edition continues to provide an enduring, practical understanding of networks and their building blocks through rich, example-based instruction. The authors' focus is on the why of network design, not just the specifications comprising today's systems but how key technologies and p

  15. Renormalization group theory of phase transitions in square Ising systems

    International Nuclear Information System (INIS)

    Nienhuis, B.

    1978-01-01

    Some renormalization group calculations are presented on a number of phase transitions in a square Ising model, both second and first order. Of these transitions critical exponents are calculated, the amplitudes of the power law divergences and the locus of the transition. In some cases attention is paid to the thermodynamic functions also far from the critical point. Universality and scaling are discussed and the renormalization group theory is reviewed. It is shown how a renormalization transformation, which relates two similar systems with different macroscopic dimensions, can be constructed, and how some critical properties of the system follow from this transformation. Several numerical and analytical applications are presented. (Auth.)

  16. Sampling algorithms for validation of supervised learning models for Ising-like systems

    Science.gov (United States)

    Portman, Nataliya; Tamblyn, Isaac

    2017-12-01

    In this paper, we build and explore supervised learning models of ferromagnetic system behavior, using Monte-Carlo sampling of the spin configuration space generated by the 2D Ising model. Given the enormous size of the space of all possible Ising model realizations, the question arises as to how to choose a reasonable number of samples that will form physically meaningful and non-intersecting training and testing datasets. Here, we propose a sampling technique called ;ID-MH; that uses the Metropolis-Hastings algorithm creating Markov process across energy levels within the predefined configuration subspace. We show that application of this method retains phase transitions in both training and testing datasets and serves the purpose of validation of a machine learning algorithm. For larger lattice dimensions, ID-MH is not feasible as it requires knowledge of the complete configuration space. As such, we develop a new ;block-ID; sampling strategy: it decomposes the given structure into square blocks with lattice dimension N ≤ 5 and uses ID-MH sampling of candidate blocks. Further comparison of the performance of commonly used machine learning methods such as random forests, decision trees, k nearest neighbors and artificial neural networks shows that the PCA-based Decision Tree regressor is the most accurate predictor of magnetizations of the Ising model. For energies, however, the accuracy of prediction is not satisfactory, highlighting the need to consider more algorithmically complex methods (e.g., deep learning).

  17. Microscopic energy flows in disordered Ising spin systems

    International Nuclear Information System (INIS)

    Agliari, E; Casartelli, M; Vezzani, A

    2010-01-01

    An efficient microcanonical dynamics has been recently introduced for Ising spin models embedded in a generic connected graph even in the presence of disorder, i.e. with the spin couplings chosen from a random distribution. Such a dynamics allows a coherent definition of local temperatures also when open boundaries are coupled to thermostats, imposing an energy flow. Within this framework, here we introduce a consistent definition for local energy currents and we study their dependence on the disorder. In the linear response regime, when the global gradient between thermostats is small, we also define local conductivities following a Fourier discretized picture. Then, we work out a linearized 'mean-field approximation', where local conductivities are supposed to depend on local couplings and temperatures only. We compare the approximated currents with the exact results of the nonlinear system, showing the reliability range of the mean-field approach, which proves very good at high temperatures and not so efficient in the critical region. In the numerical studies we focus on the disordered cylinder but our results could be extended to an arbitrary, disordered spin model on generic discrete structures

  18. Effects of the amorphization on hysteresis loops of the amorphous spin-1/2 Ising system

    International Nuclear Information System (INIS)

    Essaoudi, I.; Ainane, A.; Saber, M.; Miguel, J.J. de

    2009-01-01

    We examine the effects of the amorphization on the hysteresis loops of the amorphous spin-1/2 Ising system using the effective field theory within a probability distribution technique that accounts for the self-spin correlation functions. The magnetization, the transverse and longitudinal susceptibilities, and pyromagnetic coefficient are also studied in detail

  19. Mixed spin-5/2 and spin-2 Ising ferrimagnetic system on the Bethe lattice

    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, PB 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)

    2015-11-01

    The magnetic properties of spins-S and σ Ising model on the Bethe lattice have been investigated by using the Monte Carlo simulation. The thermal total magnetization and magnetization of spins S and σ with the different exchange interactions, different external magnetic field and different temperatures have been studied. The critical temperature and compensation temperature have been deduced. The magnetic hysteresis cycle of Ising ferrimagnetic system on the Bethe lattice has been deduced for different values of exchange interactions between the spins S and σ, for different values of crystal field and for different sizes. The magnetic coercive filed has been deduced. - Highlights: • The magnetic properties of Bethe lattice have been investigated. • The critical temperature and compensation temperature have been deduced. • The magnetic coercive filed has been deduced.

  20. The effective-field study of a mixed spin-1 and spin-5/2 Ising ferrimagnetic system

    International Nuclear Information System (INIS)

    Deviren, Bayram; Bati, Mehmet; Keskin, Mustafa

    2009-01-01

    An effective-field theory with correlations is developed for a mixed spin-1 and spin-5/2 Ising ferrimagnetic system on the honeycomb (δ=3) and square (δ=4) lattices in the absence and presence of a longitudinal magnetic field. The ground-state phase diagram of the model is obtained in the longitudinal magnetic field (h) and a single-ion potential or crystal-field interaction (Δ) plane. We also investigate the thermal variations of the sublattice magnetizations, and present the phase diagrams in the (Δ/|J|,k B T/|J|) plane. The susceptibility, internal energy and specific heat of the system are numerically examined, and some interesting phenomena in these quantities are found due to the absence and presence of the applied longitudinal magnetic field. Moreover, the system undergoes second- and first-order phase transition; hence, the system gives a tricritical point. The system also exhibits reentrant behavior.

  1. The effective-field study of a mixed spin-1 and spin-5/2 Ising ferrimagnetic system

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-06-15

    An effective-field theory with correlations is developed for a mixed spin-1 and spin-5/2 Ising ferrimagnetic system on the honeycomb ({delta}=3) and square ({delta}=4) lattices in the absence and presence of a longitudinal magnetic field. The ground-state phase diagram of the model is obtained in the longitudinal magnetic field (h) and a single-ion potential or crystal-field interaction ({delta}) plane. We also investigate the thermal variations of the sublattice magnetizations, and present the phase diagrams in the ({delta}/|J|,k{sub B}T/|J|) plane. The susceptibility, internal energy and specific heat of the system are numerically examined, and some interesting phenomena in these quantities are found due to the absence and presence of the applied longitudinal magnetic field. Moreover, the system undergoes second- and first-order phase transition; hence, the system gives a tricritical point. The system also exhibits reentrant behavior.

  2. The Glauber dynamics for a spin-1 metamagnetic Ising system with bilinear and biquadratic interactions

    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); Kantar, Ersin [Institute of Science, Erciyes University, 38039 Kayseri (Turkey)

    2009-06-15

    We present a study, within a mean-field approximation, of the dynamics of a spin-1 metamagnetic Ising system with bilinear and biquadratic interactions in the presence of a time-dependent oscillating external magnetic field. First, we employ the Glauber transition rates to construct the set of mean-field dynamic equations. Then, we study the time variation of the average order parameters to find the phases in the system. We also investigate the thermal behavior of dynamic order parameters to characterize the nature (first- or second-order) of the dynamic transitions. The dynamic phase transitions are obtained and the phase diagrams are constructed in two different the planes. The phase diagrams contain a disordered and ordered phases, and four different mixed phases that strongly depend on interaction parameters. Phase diagrams also display one or two dynamic tricritical points, a dynamic double critical end and dynamic quadruple points. A comparison is made with the results of the other metamagnetic Ising systems.

  3. The Glauber dynamics for a spin-1 metamagnetic Ising system with bilinear and biquadratic interactions

    International Nuclear Information System (INIS)

    Keskin, Mustafa; Canko, Osman; Kantar, Ersin

    2009-01-01

    We present a study, within a mean-field approximation, of the dynamics of a spin-1 metamagnetic Ising system with bilinear and biquadratic interactions in the presence of a time-dependent oscillating external magnetic field. First, we employ the Glauber transition rates to construct the set of mean-field dynamic equations. Then, we study the time variation of the average order parameters to find the phases in the system. We also investigate the thermal behavior of dynamic order parameters to characterize the nature (first- or second-order) of the dynamic transitions. The dynamic phase transitions are obtained and the phase diagrams are constructed in two different the planes. The phase diagrams contain a disordered and ordered phases, and four different mixed phases that strongly depend on interaction parameters. Phase diagrams also display one or two dynamic tricritical points, a dynamic double critical end and dynamic quadruple points. A comparison is made with the results of the other metamagnetic Ising systems.

  4. Selection rules for single-chain-magnet behaviour in non-collinear Ising systems

    Energy Technology Data Exchange (ETDEWEB)

    Vindigni, Alessandro [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zuerich (Switzerland); Pini, Maria Gloria [Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, I-50019 Sesto Fiorentino (Italy)], E-mail: vindigni@phys.ethz.ch

    2009-06-10

    The magnetic behaviour of molecular single-chain magnets is investigated in the framework of a one-dimensional Ising model with single spin-flip Glauber dynamics. Opportune modifications to the original theory are required in order to account for non-collinearity of local anisotropy axes between themselves and with respect to the crystallographic (laboratory) frame. The extension of Glauber's theory to the case of a collinear Ising ferrimagnetic chain is also discussed. Within this formalism, both the dynamics of magnetization reversal in zero field and the response of the system to a weak magnetic field, oscillating in time, are studied. Depending on the experimental geometry, selection rules are found for the occurrence of slow relaxation of the magnetization at low temperatures, as well as for resonant behaviour of the a.c. susceptibility as a function of temperature at low frequencies. The present theory applies successfully to some real systems, namely Mn-, Dy- and Co-based molecular magnetic chains, showing that single-chain-magnet behaviour is not only a feature of collinear ferro- and ferrimagnetic, but also of canted antiferromagnetic chains.

  5. Selection rules for single-chain-magnet behaviour in non-collinear Ising systems

    International Nuclear Information System (INIS)

    Vindigni, Alessandro; Pini, Maria Gloria

    2009-01-01

    The magnetic behaviour of molecular single-chain magnets is investigated in the framework of a one-dimensional Ising model with single spin-flip Glauber dynamics. Opportune modifications to the original theory are required in order to account for non-collinearity of local anisotropy axes between themselves and with respect to the crystallographic (laboratory) frame. The extension of Glauber's theory to the case of a collinear Ising ferrimagnetic chain is also discussed. Within this formalism, both the dynamics of magnetization reversal in zero field and the response of the system to a weak magnetic field, oscillating in time, are studied. Depending on the experimental geometry, selection rules are found for the occurrence of slow relaxation of the magnetization at low temperatures, as well as for resonant behaviour of the a.c. susceptibility as a function of temperature at low frequencies. The present theory applies successfully to some real systems, namely Mn-, Dy- and Co-based molecular magnetic chains, showing that single-chain-magnet behaviour is not only a feature of collinear ferro- and ferrimagnetic, but also of canted antiferromagnetic chains.

  6. Hysteresis and compensation behaviors of spin-3/2 cylindrical Ising nanotube system

    International Nuclear Information System (INIS)

    Kocakaplan, Yusuf; Keskin, Mustafa

    2014-01-01

    The hysteresis and compensation behaviors of the spin-3/2 cylindrical Ising nanotube system are studied within the framework of the effective-field theory with correlations. The effects of the Hamiltonian parameters are investigated on the magnetic and thermodynamic quantities, such as the total magnetization, hysteresis curves, and compensation behaviors of the system. Depending on the Hamiltonian parameters, some characteristic hysteresis behaviors are found, such as the existence of double and triple hysteresis loops. According to Néel classification nomenclature, the system displays Q-, R-, P-, N-, M-, and S- types of compensation behaviors for the appropriate values of the system parameters. We also compare our results with some recently published theoretical and experimental works and find a qualitatively good agreement

  7. Hysteresis and compensation behaviors of spin-3/2 cylindrical Ising nanotube system

    Energy Technology Data Exchange (ETDEWEB)

    Kocakaplan, Yusuf [Graduate School of Natural and Applied Sciences, Erciyes University, 38039 Kayseri (Turkey); Keskin, Mustafa, E-mail: keskin@erciyes.edu.tr [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

    2014-09-07

    The hysteresis and compensation behaviors of the spin-3/2 cylindrical Ising nanotube system are studied within the framework of the effective-field theory with correlations. The effects of the Hamiltonian parameters are investigated on the magnetic and thermodynamic quantities, such as the total magnetization, hysteresis curves, and compensation behaviors of the system. Depending on the Hamiltonian parameters, some characteristic hysteresis behaviors are found, such as the existence of double and triple hysteresis loops. According to Néel classification nomenclature, the system displays Q-, R-, P-, N-, M-, and S- types of compensation behaviors for the appropriate values of the system parameters. We also compare our results with some recently published theoretical and experimental works and find a qualitatively good agreement.

  8. Sound dispersion in a spin-1 Ising system near the second-order phase transition point

    International Nuclear Information System (INIS)

    Erdem, Ryza; Keskin, Mustafa

    2003-01-01

    Sound dispersion relation is derived for a spin-1 Ising system and its behaviour near the second-order phase transition point or the critical point is analyzed. The method used is a combination of molecular field approximation and Onsager theory of irreversible thermodynamics. If we assume a linear coupling of sound wave with the order parameter fluctuations in the system, we find that the dispersion which is the relative sound velocity change with frequency behaves as ω 0 ε 0 , where ω is the sound frequency and ε the temperature distance from the critical point. In the ordered region, one also observes a frequency-dependent velocity or dispersion minimum which is shifted from the corresponding attenuation maxima. These phenomena are in good agreement with the calculations of sound velocity in other magnetic systems such as magnetic metals, magnetic insulators, and magnetic semiconductors

  9. 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

  10. Analytical and computational study of magnetization switching in kinetic Ising systems with demagnetizing fields

    DEFF Research Database (Denmark)

    Richards, H.L.; Rikvold, P.A.

    1996-01-01

    particularly promising as materials for high-density magnetic recording media. In this paper we use analytic arguments and Monte Carlo simulations to quantitatively study the effects of the demagnetizing field on the dynamics of magnetization switching in two-dimensional, single-domain, kinetic Ising systems....... For systems in the weak-field ''stochastic region,'' where magnetization switching is on average effected by the nucleation and growth of a single droplet, the simulation results can be explained by a simple model in which the free energy is a function only of magnetization. In the intermediate......-field ''multidroplet region,'' a generalization of Avrami's law involving a magnetization-dependent effective magnetic field gives good agreement with the simulations. The effects of the demagnetizing field do not qualitatively change the droplet-theoretical picture of magnetization switching in highly anisotropic...

  11. Relaxation theory of spin-3/2 Ising system near phase transition temperatures

    International Nuclear Information System (INIS)

    Canko, Osman; Keskin, Mustafa

    2010-01-01

    Dynamics of a spin-3/2 Ising system Hamiltonian with bilinear and biquadratic nearest-neighbour exchange interactions is studied by a simple method in which the statistical equilibrium theory is combined with the Onsager's theory of irreversible thermodynamics. First, the equilibrium behaviour of the model in the molecular-field approximation is given briefly in order to obtain the phase transition temperatures, i.e. the first- and second-order and the tricritical points. Then, the Onsager theory is applied to the model and the kinetic or rate equations are obtained. By solving these equations three relaxation times are calculated and their behaviours are examined for temperatures near the phase transition points. Moreover, the z dynamic critical exponent is calculated and compared with the z values obtained for different systems experimentally and theoretically, and they are found to be in good agrement. (general)

  12. Quasi-one-dimensional magnetic behaviour of the Ising system CsFeCl3.2aq

    NARCIS (Netherlands)

    Kopinga, K.; Steiner, M.; Jonge, de W.J.M.

    1985-01-01

    The magnetic behaviour of the quasi-one-dimensional system CsFeCl3.2aq(aq=H2O, D2O) has been investigated by heat capacity measurements, quasi-elastic neutron scattering and spin-cluster resonance. the experiments demonstrate that below 25K the compound is a very good realisation of an (S=1/2) Ising

  13. Linear perturbation renormalization group method for Ising-like spin systems

    Directory of Open Access Journals (Sweden)

    J. Sznajd

    2013-03-01

    Full Text Available The linear perturbation group transformation (LPRG is used to study the thermodynamics of the axial next-nearest-neighbor Ising model with four spin interactions (extended ANNNI in a field. The LPRG for weakly interacting Ising chains is presented. The method is used to study finite field para-ferrimagnetic phase transitions observed in layered uranium compounds, UAs1-xSex, UPd2Si2 or UNi2Si2. The above-mentioned systems are made of ferromagnetic layers and the spins from the nearest-neighbor and next-nearest-neighbor layers are coupled by the antiferromagnetic interactions J121-xSex the para-ferri phase transition is of the first order as expected from the symmetry reason, in UT2Si2 (T=Pd, Ni this transition seems to be a continuous one, at least in the vicinity of the multicritical point. Within the MFA, the critical character of the finite field para-ferrimagnetic transition at least at one isolated point can be described by the ANNNI model supplemented by an additional, e.g., four-spin interaction. However, in LPRG approximation for the ratio κ = J2/J1 around 0.5 there is a critical value of the field for which an isolated critical point also exists in the original ANNNI model. The positive four-spin interaction shifts the critical point towards higher fields and changes the shape of the specific heat curve. In the latter case for the fields small enough, the specific heat exhibits two-peak structure in the paramagnetic phase.

  14. ISE and Chemfet sensors in greenhouse cultivation

    NARCIS (Netherlands)

    Gieling, T.H.; Straten, van G.; Janssen, H.J.J.; Wouters, H.

    2005-01-01

    The development and market introduction of ion-specific sensors, like the ion selective electrode (ISE) and ion selective field effect transistor (ISFET) sensor, has paved the way for completely new systems for application of fertilisers to crops in greenhouses. This paper illustrates the usefulness

  15. Thermal hysteresis kinetic effects of spin crossover nanoparticulated systems studied by FORC diagram method on an Ising-like model

    International Nuclear Information System (INIS)

    Atitoaie, Alexandru; Stoleriu, Laurentiu; Tanasa, Radu; Stancu, Alexandru; Enachescu, Cristian

    2016-01-01

    The scientific community is manifesting a high research interest on spin crossover compounds and their recently synthesized nanoparticles, due to their various appealing properties, such as the bistability between a diamagnetic low spin state and a paramagnetic high spin state (HS), inter-switchable by temperature or pressure changes, light irradiation or magnetic field. The utility of these compounds showing hysteresis covers a broad area of applications, from the development of more efficient designs of temperature and pressure sensors to automotive and aeronautic industries and even a new type of molecular actuators. We are proposing in this work a study regarding the kinetic effects and the distribution of reversible and irreversible components on the thermal hysteresis of spin crossover nanoparticulated systems. We are considering here tridimensional systems with different sizes and also systems of nanoparticles with a Gaussian size distribution. The correlations between the kinetics of the thermal hysteresis, the distributions of sizes and intermolecular interactions and the transition temperature distributions were established by using the FORC (First Order Reversal Curves) method using a Monte Carlo technique within an Ising-like system.

  16. Thermal hysteresis kinetic effects of spin crossover nanoparticulated systems studied by FORC diagram method on an Ising-like model

    Energy Technology Data Exchange (ETDEWEB)

    Atitoaie, Alexandru, E-mail: atitoaie@phys-iasi.ro [Department. of Physics, “Alexandru Ioan Cuza” University, 700506 Iasi (Romania); National Institute of Research and Development for Technical Physics, Iasi (Romania); Stoleriu, Laurentiu [Department. of Physics, “Alexandru Ioan Cuza” University, 700506 Iasi (Romania); Tanasa, Radu [Department. of Physics, “Alexandru Ioan Cuza” University, 700506 Iasi (Romania); Department of Engineering, University of Cambridge, CB2 1PZ Cambridge (United Kingdom); Stancu, Alexandru; Enachescu, Cristian [Department. of Physics, “Alexandru Ioan Cuza” University, 700506 Iasi (Romania)

    2016-04-01

    The scientific community is manifesting a high research interest on spin crossover compounds and their recently synthesized nanoparticles, due to their various appealing properties, such as the bistability between a diamagnetic low spin state and a paramagnetic high spin state (HS), inter-switchable by temperature or pressure changes, light irradiation or magnetic field. The utility of these compounds showing hysteresis covers a broad area of applications, from the development of more efficient designs of temperature and pressure sensors to automotive and aeronautic industries and even a new type of molecular actuators. We are proposing in this work a study regarding the kinetic effects and the distribution of reversible and irreversible components on the thermal hysteresis of spin crossover nanoparticulated systems. We are considering here tridimensional systems with different sizes and also systems of nanoparticles with a Gaussian size distribution. The correlations between the kinetics of the thermal hysteresis, the distributions of sizes and intermolecular interactions and the transition temperature distributions were established by using the FORC (First Order Reversal Curves) method using a Monte Carlo technique within an Ising-like system.

  17. Ordering kinetics in quasi-one-dimensional Ising-like systems

    International Nuclear Information System (INIS)

    Mueller, M.; Paul, W.

    1993-01-01

    Results are presented of a Monte Carlo simulation of the kinetics of ordering in the two-dimensional nearest-neighbor Ising model in an L x M geometry with two free boundaries of length M much-gt L. This model can be viewed as representing an adsorbant on a stepped surface with mean terrace width L. The authors follow the ordering kinetics after quenches to temperatures 0.25 ≤T/T c ≤1 starting from a random initial configuration at a coverage of Θ=0.5 in the corresponding lattice gas picture. The systems evolve in time according to a Glauber kinetics with nonconserved order parameter. The equilibrium structure is given by a one-dimensional sequence of ordered domains. The ordering process evolves from a short initial two-dimensional ordering process through a crossover region to a quasi-one-dimensional behavior. The whole process is diffusive (inverse half-width of the structure factor peak 1/Δq parallel ∝ √t), in contrast to a model proposed by Kawasaki et al., where an intermediate logarithmic growth law is expected. All results are completely describable in the picture of an annihilating random walk (ARW) of domain walls. 36 refs., 16 figs

  18. Critical behavior of magnetization in URhAl: Quasi-two-dimensional Ising system with long-range interactions

    Science.gov (United States)

    Tateiwa, Naoyuki; Pospíšil, Jiří; Haga, Yoshinori; Yamamoto, Etsuji

    2018-02-01

    The critical behavior of dc magnetization in the uranium ferromagnet URhAl with the hexagonal ZrNiAl-type crystal structure has been studied around the ferromagnetic transition temperature TC. The critical exponent β for the temperature dependence of the spontaneous magnetization below TC,γ for the magnetic susceptibility, and δ for the magnetic isotherm at TC, have been obtained with a modified Arrott plot, a Kouvel-Fisher plot, the critical isotherm analysis, and the scaling analysis. We have determined the critical exponents as β =0.287 ±0.005 , γ =1.47 ±0.02 , and δ =6.08 ±0.04 by the scaling analysis and the critical isotherm analysis. These critical exponents satisfy the Widom scaling law δ =1 +γ /β . URhAl has strong uniaxial magnetic anisotropy, similar to its isostructural UCoAl that has been regarded as a three-dimensional (3D) Ising system in previous studies. However, the universality class of the critical phenomenon in URhAl does not belong to the 3D Ising model (β =0.325 , γ =1.241 , and δ =4.82 ) with short-range exchange interactions between magnetic moments. The determined exponents can be explained with the results of the renormalization group approach for a two-dimensional (2D) Ising system coupled with long-range interactions decaying as J (r ) ˜r-(d +σ ) with σ =1.44 . We suggest that the strong hybridization between the uranium 5 f and rhodium 4 d electrons in the U-RhI layer in the hexagonal crystal structure is a source of the low-dimensional magnetic property. The present result is contrary to current understandings of the physical properties in a series of isostructural UTX uranium ferromagnets (T: transition metals, X: p -block elements) based on the 3D Ising model.

  19. Generic Ising trees

    DEFF Research Database (Denmark)

    Durhuus, Bergfinnur Jøgvan; Napolitano, George Maria

    2012-01-01

    The Ising model on a class of infinite random trees is defined as a thermodynamiclimit of finite systems. A detailed description of the corresponding distribution of infinite spin configurations is given. As an application, we study the magnetization properties of such systems and prove that they......The Ising model on a class of infinite random trees is defined as a thermodynamiclimit of finite systems. A detailed description of the corresponding distribution of infinite spin configurations is given. As an application, we study the magnetization properties of such systems and prove...... that they exhibit no spontaneous magnetization. Furthermore, the values of the Hausdorff and spectral dimensions of the underlying trees are calculated and found to be, respectively,¯dh =2 and¯ds = 4/3....

  20. From tricritical Ising to critical Ising by thermodynamic Bethe ansatz

    International Nuclear Information System (INIS)

    Zamolodchikov, A.B.

    1991-01-01

    A simple factorized scattering theory is suggested for the massless Goldstone fermions of the trajectory flowing from the tricritical Ising fixed point to the critical Ising one. The thermodynamic Bethe ansatz approach is applied to this scattering theory to support its interpretation both analytically and numerically. As a generalization a sequence of massless TBA systems is proposed which seems relevant for the trajectories interpolating between two successive minimal CFT models M p and M p-1 . (orig.)

  1. Entanglement and quantum state geometry of a spin system with all-range Ising-type interaction

    Science.gov (United States)

    Kuzmak, A. R.

    2018-04-01

    The evolution of an N spin-1/2 system with all-range Ising-type interaction is considered. For this system we study the entanglement of one spin with the rest spins. It is shown that the entanglement depends on the number of spins and the initial state. Also, the geometry of the manifold, which contains entangled states, is obtained. For this case we find the dependence of entanglement on the scalar curvature of the manifold and examine it for different numbers of spins in the system. Finally we show that the transverse magnetic field leads to a change in the manifold topology.

  2. Monte Carlo method for critical systems in infinite volume: The planar Ising model.

    Science.gov (United States)

    Herdeiro, Victor; Doyon, Benjamin

    2016-10-01

    In this paper we propose a Monte Carlo method for generating finite-domain marginals of critical distributions of statistical models in infinite volume. The algorithm corrects the problem of the long-range effects of boundaries associated to generating critical distributions on finite lattices. It uses the advantage of scale invariance combined with ideas of the renormalization group in order to construct a type of "holographic" boundary condition that encodes the presence of an infinite volume beyond it. We check the quality of the distribution obtained in the case of the planar Ising model by comparing various observables with their infinite-plane prediction. We accurately reproduce planar two-, three-, and four-point of spin and energy operators. We also define a lattice stress-energy tensor, and numerically obtain the associated conformal Ward identities and the Ising central charge.

  3. Dynamic Phase Transitions In The Spin-2 Ising System Under An Oscillating Magnetic Field Within The Effective-Field Theory

    International Nuclear Information System (INIS)

    Ertas, Mehmet; Keskin, Mustafa; Deviren, Bayram

    2010-01-01

    The dynamic phase transitions are studied in the spin-2 Ising model under a time-dependent oscillating magnetic field by using the effective-field theory with correlations. The effective-field dynamic equation 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 order parameter and the dynamic phase transition temperatures are obtained. The dynamic phase diagrams are presented in (T/zJ, h/zJ) plane.

  4. Statistical Mechanics of Coherent Ising Machine — The Case of Ferromagnetic and Finite-Loading Hopfield Models —

    Science.gov (United States)

    Aonishi, Toru; Mimura, Kazushi; Utsunomiya, Shoko; Okada, Masato; Yamamoto, Yoshihisa

    2017-10-01

    The coherent Ising machine (CIM) has attracted attention as one of the most effective Ising computing architectures for solving large scale optimization problems because of its scalability and high-speed computational ability. However, it is difficult to implement the Ising computation in the CIM because the theories and techniques of classical thermodynamic equilibrium Ising spin systems cannot be directly applied to the CIM. This means we have to adapt these theories and techniques to the CIM. Here we focus on a ferromagnetic model and a finite loading Hopfield model, which are canonical models sharing a common mathematical structure with almost all other Ising models. We derive macroscopic equations to capture nonequilibrium phase transitions in these models. The statistical mechanical methods developed here constitute a basis for constructing evaluation methods for other Ising computation models.

  5. AIM for Allostery: Using the Ising Model to Understand Information Processing and Transmission in Allosteric Biomolecular Systems.

    Science.gov (United States)

    LeVine, Michael V; Weinstein, Harel

    2015-05-01

    In performing their biological functions, molecular machines must process and transmit information with high fidelity. Information transmission requires dynamic coupling between the conformations of discrete structural components within the protein positioned far from one another on the molecular scale. This type of biomolecular "action at a distance" is termed allostery . Although allostery is ubiquitous in biological regulation and signal transduction, its treatment in theoretical models has mostly eschewed quantitative descriptions involving the system's underlying structural components and their interactions. Here, we show how Ising models can be used to formulate an approach to allostery in a structural context of interactions between the constitutive components by building simple allosteric constructs we termed Allosteric Ising Models (AIMs). We introduce the use of AIMs in analytical and numerical calculations that relate thermodynamic descriptions of allostery to the structural context, and then show that many fundamental properties of allostery, such as the multiplicative property of parallel allosteric channels, are revealed from the analysis of such models. The power of exploring mechanistic structural models of allosteric function in more complex systems by using AIMs is demonstrated by building a model of allosteric signaling for an experimentally well-characterized asymmetric homodimer of the dopamine D2 receptor.

  6. Quantum kinetic Ising models

    International Nuclear Information System (INIS)

    Augusiak, R; Cucchietti, F M; Lewenstein, M; Haake, F

    2010-01-01

    In this paper, we introduce a quantum generalization of classical kinetic Ising models (KIM), described by a certain class of quantum many-body master equations. Similarly to KIMs with detailed balance that are equivalent to certain Hamiltonian systems, our models reduce to a set of Hamiltonian systems determining the dynamics of the elements of the many-body density matrix. The ground states of these Hamiltonians are well described by the matrix product, or pair entangled projected states. We discuss critical properties of such Hamiltonians, as well as entanglement properties of their low-energy states.

  7. Theory of relaxation phenomena in a spin-3/2 Ising system near the second-order phase transition temperature

    International Nuclear Information System (INIS)

    Keskin, Mustafa; Canko, Osman

    2005-01-01

    The relaxation behavior of the spin-3/2 Ising model Hamiltonian with bilinear and biquadratic interactions near the second-order phase transition temperature or critical temperature is studied by means of the Onsager's theory of irreversible thermodynamics or the Onsager reciprocity theorem (ORT). First, we give the equilibrium case briefly within the molecular-field approximation in order to study the relaxation behavior by using the ORT. Then, the ORT is applied to the model and the kinetic equations are obtained. By solving these equations, three relaxation times are calculated and examined for temperatures near the second-order phase transition temperature. It is found that one of the relaxation times goes to infinity near the critical temperature on either side, the second relaxation time makes a cusp at the critical temperature and third one behaves very differently in which it terminates at the critical temperature while approaching it, then showing a 'flatness' property and then decreases. We also study the influences of the Onsager rate coefficients on the relaxation times. The behavior of these relaxation times is discussed and compared with the spin-1/2 and spin-1 Ising systems

  8. Pengembangan Indentation Size Effect (ISE Dalam Penentuan Koefisien Pengerasan Regang Baja

    Directory of Open Access Journals (Sweden)

    I Nyoman Budiarsa

    2016-07-01

    /E ratio. ISE scale of the samples tested showed consistent repeatability and strongly associated with material properties significantly. This case has the potential to provide experimental data set that reflects the material properties associated with Strain gradient and dislocation density during the indentation process. The concept for using Vickers indentation size data have been developed to improve the accuracy of inverse modeling based of hardness using steel as a material system. This study shows that there are significant ISE in which the Vickers hardness test scale and reliability of ISE analyzed by fitting data following the Power Law and Proportional Resistance Model. A new concept of using ISE data for estimating the Strain hardening exponent (n values of steel has been evaluated and shown reasonable results for narrowing the range of predicted material properties based on hardness values Keywords: ISE, H/E ratio, Strain hardening exponent (n

  9. Compiling gate networks on an Ising quantum computer

    International Nuclear Information System (INIS)

    Bowdrey, M.D.; Jones, J.A.; Knill, E.; Laflamme, R.

    2005-01-01

    Here we describe a simple mechanical procedure for compiling a quantum gate network into the natural gates (pulses and delays) for an Ising quantum computer. The aim is not necessarily to generate the most efficient pulse sequence, but rather to develop an efficient compilation algorithm that can be easily implemented in large spin systems. The key observation is that it is not always necessary to refocus all the undesired couplings in a spin system. Instead, the coupling evolution can simply be tracked and then corrected at some later time. Although described within the language of NMR, the algorithm is applicable to any design of quantum computer based on Ising couplings

  10. Magnetization plateaus of the frustrated Ising Shastry–Sutherland system: Wang–Landau simulation

    International Nuclear Information System (INIS)

    Lin, W.S.; Yang, T.H.; Wang, Y.; Qin, M.H.; Liu, J.-M.; Ren, Zhifeng

    2014-01-01

    The Wang–Landau algorithm is used to study the magnetic properties of the Ising model on the Shastry–Sutherland lattice in order to understand the interesting magnetization plateaus observed in TmB 4 . The simulated results demonstrate that the equilibrium state of the model produces only the 1/3 and 1/2 magnetization plateaus at low temperatures even when the random-exchange term or the long-range interactions are taken into account. This confirms our earlier conclusion (Huang et al., 2013) [20] that those fractional plateaus observed in experiments may be due to the magnetization dynamics. - Highlights: • The magnetic behaviors of TmB 4 are investigated using the Wang–Landau method. • The equilibrium state only produces the 1/3 and 1/2 magnetization plateaus. • Those fractional plateaus must arise from the non-equilibrium magnetization

  11. Magnetization plateaus of the frustrated Ising Shastry–Sutherland system: Wang–Landau simulation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, W.S.; Yang, T.H.; Wang, Y. [Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou 510006 (China); Qin, M.H., E-mail: qinmh@scnu.edu.cn [Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou 510006 (China); Department of Physics and TcSUH, University of Houston, Houston, TX 77204 (United States); Liu, J.-M. [Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Ren, Zhifeng, E-mail: zren@uh.edu [Department of Physics and TcSUH, University of Houston, Houston, TX 77204 (United States)

    2014-07-04

    The Wang–Landau algorithm is used to study the magnetic properties of the Ising model on the Shastry–Sutherland lattice in order to understand the interesting magnetization plateaus observed in TmB{sub 4}. The simulated results demonstrate that the equilibrium state of the model produces only the 1/3 and 1/2 magnetization plateaus at low temperatures even when the random-exchange term or the long-range interactions are taken into account. This confirms our earlier conclusion (Huang et al., 2013) [20] that those fractional plateaus observed in experiments may be due to the magnetization dynamics. - Highlights: • The magnetic behaviors of TmB{sub 4} are investigated using the Wang–Landau method. • The equilibrium state only produces the 1/3 and 1/2 magnetization plateaus. • Those fractional plateaus must arise from the non-equilibrium magnetization.

  12. Magnetic properties of a ferromagnet spin-S, Ising, XY and Heisenberg models semi-infinites systems

    International Nuclear Information System (INIS)

    Masrour, R.; Hamedoun, M.; Hourmatallah, A.; Bouslykhane, K.; Benzakour, N.

    2008-01-01

    The magnetic properties of a ferromagnet spin-S a disordered semi-infinite system with a face-centered cubic lattice are investigated using the high-temperature series expansions technique extrapolated with Pade approximants method for Heisenberg, XY and Ising models. The reduced critical temperature of the system τ c =(k B T c )/(2S(S+1)J b ) is studied as function of the thickness of the film and the exchange interactions in the bulk, and within the surfaces J b ,J s and J perpendicular , respectively. It is found that τ c increases with the exchange interactions of surface. The magnetic phase diagrams (τ c versus the dilution x) and the percolation threshold are obtained

  13. One-dimensional Ising model with multispin interactions

    Science.gov (United States)

    Turban, Loïc

    2016-09-01

    We study the spin-1/2 Ising chain with multispin interactions K involving the product of m successive spins, for general values of m. Using a change of spin variables the zero-field partition function of a finite chain is obtained for free and periodic boundary conditions and we calculate the two-spin correlation function. When placed in an external field H the system is shown to be self-dual. Using another change of spin variables the one-dimensional Ising model with multispin interactions in a field is mapped onto a zero-field rectangular Ising model with first-neighbour interactions K and H. The 2D system, with size m × N/m, has the topology of a cylinder with helical BC. In the thermodynamic limit N/m\\to ∞ , m\\to ∞ , a 2D critical singularity develops on the self-duality line, \\sinh 2K\\sinh 2H=1.

  14. 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

  15. Zero temperature renormalisation group study of the random systems: The Ising model in a transverse field in two dimensions

    International Nuclear Information System (INIS)

    Kamieniarz, G.

    1984-12-01

    A zero temperature real space renormalization group block method is applied to the random quantum Ising model with a transverse field on the planar honeycomb and square lattices. For the bond diluted system the magnetisation and the separation of the ground state energy level (in the paramagnetic phase) are presented for several bond concentrations p. The critical exponents extracted both from the fixed-points and from direct numerical computations preserve some scaling relations, and the critical curve displays a characteristic discontinuity at the percolation concentration. For the McCoy and Wu distribution the random fields and bonds are found to introduce a strong relevant disorder. The order parameter still falls off continuously to zero for well-defined values of the parameters, but a new fixed point yields a slight change in the critical exponents. (author)

  16. Phase diagrams of a nonequilibrium mixed spin-3/2 and spin-2 Ising system in an oscillating magnetic field

    International Nuclear Information System (INIS)

    Keskin, Mustafa; Polat, Yasin

    2009-01-01

    The phase diagrams of the nonequilibrium mixed spin-3/2 and spin-2 Ising ferrimagnetic system on square lattice under a time-dependent external magnetic field are presented by using the Glauber-type stochastic dynamics. The model system consists of two interpenetrating sublattices of spins σ=3/2 and S=2, and we take only nearest-neighbor interactions between pairs of spins. The system is in contact with a heat bath at absolute temperature T abs and the exchange of energy with the heat bath occurs via one-spin flip of the Glauber dynamics. First, we investigate the time variations of average order parameters to find the phases in the system and then the thermal behavior of the dynamic order parameters to obtain the dynamic phase transition (DPT) points as well as to characterize the nature (first- or second-order) phase transitions. The dynamic phase diagrams are presented in two different planes. Phase diagrams contain paramagnetic (p), ferrimagnetic (i 1 , i 2 , i 3 ) phases, and three coexistence or mixed phase regions, namely i 1 +p, i 2 +p and i 3 +p mixed phases that strongly depend on interaction parameters.

  17. Phase diagrams of a nonequilibrium mixed spin-3/2 and spin-2 Ising system in an oscillating magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)], E-mail: keskin@erciyes.edu.tr; Polat, Yasin [Institutes of Science, Erciyes University, 38039 Kayseri (Turkey)

    2009-12-15

    The phase diagrams of the nonequilibrium mixed spin-3/2 and spin-2 Ising ferrimagnetic system on square lattice under a time-dependent external magnetic field are presented by using the Glauber-type stochastic dynamics. The model system consists of two interpenetrating sublattices of spins {sigma}=3/2 and S=2, and we take only nearest-neighbor interactions between pairs of spins. The system is in contact with a heat bath at absolute temperature T{sub abs} and the exchange of energy with the heat bath occurs via one-spin flip of the Glauber dynamics. First, we investigate the time variations of average order parameters to find the phases in the system and then the thermal behavior of the dynamic order parameters to obtain the dynamic phase transition (DPT) points as well as to characterize the nature (first- or second-order) phase transitions. The dynamic phase diagrams are presented in two different planes. Phase diagrams contain paramagnetic (p), ferrimagnetic (i{sub 1}, i{sub 2}, i{sub 3}) phases, and three coexistence or mixed phase regions, namely i{sub 1}+p, i{sub 2}+p and i{sub 3}+p mixed phases that strongly depend on interaction parameters.

  18. Dynamic compensation temperatures in a mixed spin-1 and spin-3/2 Ising system under a time-dependent oscillating magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Keskin, Mustafa, E-mail: keskin@erciyes.edu.t [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Kantar, Ersin [Institute of Science, Erciyes University, 38039 Kayseri (Turkey)

    2010-09-15

    We study the existence of dynamic compensation temperatures in the mixed spin-1 and spin-3/2 Ising ferrimagnetic system Hamiltonian with bilinear and crystal-field interactions in the presence of a time-dependent oscillating external magnetic field on a hexagonal lattice. We employ the Glauber transitions rates to construct the mean-field dynamic equations. We investigate the time dependence of an average sublattice magnetizations, the thermal behavior of the dynamic sublattice magnetizations and the total magnetization. From these studies, we find the phases in the system, and characterize the nature (continuous or discontinuous) of transitions as well as obtain the dynamic phase transition (DPT) points and the dynamic compensation temperatures. We also present dynamic phase diagrams, including the compensation temperatures, in the five different planes. A comparison is made with the results of the available mixed spin Ising systems.

  19. Dynamic compensation temperatures in a mixed spin-1 and spin-3/2 Ising system under a time-dependent oscillating magnetic field

    International Nuclear Information System (INIS)

    Keskin, Mustafa; Kantar, Ersin

    2010-01-01

    We study the existence of dynamic compensation temperatures in the mixed spin-1 and spin-3/2 Ising ferrimagnetic system Hamiltonian with bilinear and crystal-field interactions in the presence of a time-dependent oscillating external magnetic field on a hexagonal lattice. We employ the Glauber transitions rates to construct the mean-field dynamic equations. We investigate the time dependence of an average sublattice magnetizations, the thermal behavior of the dynamic sublattice magnetizations and the total magnetization. From these studies, we find the phases in the system, and characterize the nature (continuous or discontinuous) of transitions as well as obtain the dynamic phase transition (DPT) points and the dynamic compensation temperatures. We also present dynamic phase diagrams, including the compensation temperatures, in the five different planes. A comparison is made with the results of the available mixed spin Ising systems.

  20. Highly optimized simulations on single- and multi-GPU systems of the 3D Ising spin glass model

    Science.gov (United States)

    Lulli, M.; Bernaschi, M.; Parisi, G.

    2015-11-01

    We present a highly optimized implementation of a Monte Carlo (MC) simulator for the three-dimensional Ising spin-glass model with bimodal disorder, i.e., the 3D Edwards-Anderson model running on CUDA enabled GPUs. Multi-GPU systems exchange data by means of the Message Passing Interface (MPI). The chosen MC dynamics is the classic Metropolis one, which is purely dissipative, since the aim was the study of the critical off-equilibrium relaxation of the system. We focused on the following issues: (i) the implementation of efficient memory access patterns for nearest neighbours in a cubic stencil and for lagged-Fibonacci-like pseudo-Random Numbers Generators (PRNGs); (ii) a novel implementation of the asynchronous multispin-coding Metropolis MC step allowing to store one spin per bit and (iii) a multi-GPU version based on a combination of MPI and CUDA streams. Cubic stencils and PRNGs are two subjects of very general interest because of their widespread use in many simulation codes.

  1. Statistical mechanics of the cluster Ising model

    International Nuclear Information System (INIS)

    Smacchia, Pietro; Amico, Luigi; Facchi, Paolo; Fazio, Rosario; Florio, Giuseppe; Pascazio, Saverio; Vedral, Vlatko

    2011-01-01

    We study a Hamiltonian system describing a three-spin-1/2 clusterlike interaction competing with an Ising-like antiferromagnetic interaction. We compute free energy, spin-correlation functions, and entanglement both in the ground and in thermal states. The model undergoes a quantum phase transition between an Ising phase with a nonvanishing magnetization and a cluster phase characterized by a string order. Any two-spin entanglement is found to vanish in both quantum phases because of a nontrivial correlation pattern. Nevertheless, the residual multipartite entanglement is maximal in the cluster phase and dependent on the magnetization in the Ising phase. We study the block entropy at the critical point and calculate the central charge of the system, showing that the criticality of the system is beyond the Ising universality class.

  2. Statistical mechanics of the cluster Ising model

    Energy Technology Data Exchange (ETDEWEB)

    Smacchia, Pietro [SISSA - via Bonomea 265, I-34136, Trieste (Italy); Amico, Luigi [CNR-MATIS-IMM and Dipartimento di Fisica e Astronomia Universita di Catania, C/O ed. 10, viale Andrea Doria 6, I-95125 Catania (Italy); Facchi, Paolo [Dipartimento di Matematica and MECENAS, Universita di Bari, I-70125 Bari (Italy); INFN, Sezione di Bari, I-70126 Bari (Italy); Fazio, Rosario [NEST, Scuola Normale Superiore and Istituto Nanoscienze - CNR, 56126 Pisa (Italy); Center for Quantum Technology, National University of Singapore, 117542 Singapore (Singapore); Florio, Giuseppe; Pascazio, Saverio [Dipartimento di Fisica and MECENAS, Universita di Bari, I-70126 Bari (Italy); INFN, Sezione di Bari, I-70126 Bari (Italy); Vedral, Vlatko [Center for Quantum Technology, National University of Singapore, 117542 Singapore (Singapore); Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Department of Physics, University of Oxford, Clarendon Laboratory, Oxford, OX1 3PU (United Kingdom)

    2011-08-15

    We study a Hamiltonian system describing a three-spin-1/2 clusterlike interaction competing with an Ising-like antiferromagnetic interaction. We compute free energy, spin-correlation functions, and entanglement both in the ground and in thermal states. The model undergoes a quantum phase transition between an Ising phase with a nonvanishing magnetization and a cluster phase characterized by a string order. Any two-spin entanglement is found to vanish in both quantum phases because of a nontrivial correlation pattern. Nevertheless, the residual multipartite entanglement is maximal in the cluster phase and dependent on the magnetization in the Ising phase. We study the block entropy at the critical point and calculate the central charge of the system, showing that the criticality of the system is beyond the Ising universality class.

  3. Comparable studies of magnetic properties of Ising spins-5/2 and 3/2 systems on decorated square and triangular lattices

    International Nuclear Information System (INIS)

    Masrour, R.; Jabar, A.; Benyoussef, A.; Hamedoun, M.

    2016-01-01

    In this work, we have studied and compared the magnetic properties of Ising spins-5/2 and 3/2 systems on decorated square and triangular lattices using the Monte Carlo simulations. The transition temperature of the two-dimensional decorated square and triangular lattices has been obtained. The effect of the exchange interactions and crystal field on the magnetization is investigated. The magnetic coercive field and saturation magnetization of the two-dimensional decorated square and triangular lattices have been obtained.

  4. Comparable studies of magnetic properties of Ising spins-5/2 and 3/2 systems on decorated square and triangular lattices

    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); Jabar, A. [Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University, National School of Applied Sciences, 63 46000 Safi (Morocco); Benyoussef, A. [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)

    2016-07-15

    In this work, we have studied and compared the magnetic properties of Ising spins-5/2 and 3/2 systems on decorated square and triangular lattices using the Monte Carlo simulations. The transition temperature of the two-dimensional decorated square and triangular lattices has been obtained. The effect of the exchange interactions and crystal field on the magnetization is investigated. The magnetic coercive field and saturation magnetization of the two-dimensional decorated square and triangular lattices have been obtained.

  5. Frustrated lattices of Ising chains

    International Nuclear Information System (INIS)

    Kudasov, Yurii B; Korshunov, Aleksei S; Pavlov, V N; Maslov, Dmitrii A

    2012-01-01

    The magnetic structure and magnetization dynamics of systems of plane frustrated Ising chain lattices are reviewed for three groups of compounds: Ca 3 Co 2 O 6 , CsCoCl 3 , and Sr 5 Rh 4 O 12 . The available experimental data are analyzed and compared in detail. It is shown that a high-temperature magnetic phase on a triangle lattice is normally and universally a partially disordered antiferromagnetic (PDA) structure. The diversity of low-temperature phases results from weak interactions that lift the degeneracy of a 2D antiferromagnetic Ising model on the triangle lattice. Mean-field models, Monte Carlo simulation results on the static magnetization curve, and results on slow magnetization dynamics obtained with Glauber's theory are discussed in detail. (reviews of topical problems)

  6. CRISTAL-ISE your project

    CERN Document Server

    Rosaria Marraffino

    2014-01-01

    CRISTAL-ISE, a new version of the CRISTAL data tracking software developed at CERN in the late 90s, has recently been launched under an open source license. The potential for applications of this free software outside particle physics covers several areas, including medicine, where CRISTAL-ISE helps to monitor the progress of Alzheimer’s Disease.   CMS lead tungstate crystals produced in Russia. CRISTAL began as a collaboration between CERN, the University of the West of England (UWE) and the Centre National de la Recherche Scientifique (CNRS).“At the time of CMS’s construction, there was a need for software able to track the production of the almost 80,000 lead tungstate crystals for the Electromagnetic Calorimeter,” explains Andrew Branson, member of the CMS collaboration and Technical Coordinator of the CRISTAL-ISE project. “We started to develop the software when we didn’t yet know the detector testing procedures to go through,...

  7. Monte Carlo study of alternate mixed spin-5/2 and spin-2 Ising ferrimagnetic system on the Bethe lattice

    Energy Technology Data Exchange (ETDEWEB)

    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); Masrour, R., E-mail: rachidmasrour@hotmail.com [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); Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University, National School of Applied Sciences, PB 63 46000 Safi (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)

    2016-01-01

    The magnetic properties of alternate mixed spin-5/2 and spin-2 Ising model on the Bethe lattice have been studied by using the Monte Carlo simulations. The ground state phase diagrams of alternate mixed spin-5/2 and spin-2 Ising model on the Bethe lattice has been obtained. The thermal total magnetization and magnetization of spins-5/2 and spin-2 with the different exchange interactions, external magnetic field and temperatures have been studied. The critical temperature have been deduced. The magnetic hysteresis cycle on the Bethe lattice has been deduced for different values of exchange interactions, for different values of crystal field and for different sizes. The magnetic coercive field has been deduced. - Highlights: • The alternate mixed spin-5/2 and -2 on the Bethe lattice is studied. • The critical temperature has been deduced. • The magnetic coercive filed has been deduced.

  8. Stable, metastable and unstable solutions of a spin-1 Ising system based on the free energy surfaces

    Science.gov (United States)

    Keskİin, Mustafa; Özgan, Şükrü

    1990-04-01

    Stable, metastable and unstable solutions of a spin-1 Ising model with bilinear and biquadratic interactions are found by using the free energy surfaces. The free energy expression is obtained in the lowest approximation of the cluster variation method. All these solutions are shown in the two-dimensional phase space, especially the unstable solutions which in some cases are difficult to illustrate in the two-dimensional phase space, found by Keskin et al. recently.

  9. Inverse Ising inference with correlated samples

    International Nuclear Information System (INIS)

    Obermayer, Benedikt; Levine, Erel

    2014-01-01

    Correlations between two variables of a high-dimensional system can be indicative of an underlying interaction, but can also result from indirect effects. Inverse Ising inference is a method to distinguish one from the other. Essentially, the parameters of the least constrained statistical model are learned from the observed correlations such that direct interactions can be separated from indirect correlations. Among many other applications, this approach has been helpful for protein structure prediction, because residues which interact in the 3D structure often show correlated substitutions in a multiple sequence alignment. In this context, samples used for inference are not independent but share an evolutionary history on a phylogenetic tree. Here, we discuss the effects of correlations between samples on global inference. Such correlations could arise due to phylogeny but also via other slow dynamical processes. We present a simple analytical model to address the resulting inference biases, and develop an exact method accounting for background correlations in alignment data by combining phylogenetic modeling with an adaptive cluster expansion algorithm. We find that popular reweighting schemes are only marginally effective at removing phylogenetic bias, suggest a rescaling strategy that yields better results, and provide evidence that our conclusions carry over to the frequently used mean-field approach to the inverse Ising problem. (paper)

  10. Phase transitions and multicritical points in the mixed spin-32 and spin-2 Ising system with a single-ion anisotropy

    International Nuclear Information System (INIS)

    Bobak, A.; Dely, J.

    2007-01-01

    The effect of a single-ion anisotropy on the phase diagram of the mixed spin-32 and spin-2 Ising system is investigated by the use of a mean-field theory based on the Bogoliubov inequality for the free energy. Topologically different kinds of phase diagrams are achieved by changing values of the parameter in the model Hamiltonian. Besides second-order transitions, lines of first-order transitions terminating either at a tricritical point or an isolated critical point, are found

  11. Testing Efficiency of Derivative Markets: ISE30, ISE100, USD and EURO

    OpenAIRE

    Akal, Mustafa; Birgili, Erhan; Durmuskaya, Sedat

    2012-01-01

    This study attempts to develop new market efficiency tests depending on the spot and future prices, or the differences of them alternative to traditional unit root test build on univariate time series. As a result of the autocorrelation, normality and run tests applied to spot and futures prices or differences of them, and Adopted Purchasing Power Parity test based on a regression the future markets of ISE30, ISE100 index indicators, USD and Euro currencies, all of which have been traded dail...

  12. Quantum Ising model on hierarchical structures

    International Nuclear Information System (INIS)

    Lin Zhifang; Tao Ruibao.

    1989-11-01

    A quantum Ising chain with both the exchange couplings and the transverse fields arranged in a hierarchical way is considered. Exact analytical results for the critical line and energy gap are obtained. It is shown that when R 1 not= R 2 , where R 1 and R 2 are the hierarchical parameters for the exchange couplings and the transverse fields, respectively, the system undergoes a phase transition in a different universality class from the pure quantum Ising chain with R 1 =R 2 =1. On the other hand, when R 1 =R 2 =R, there exists a critical value R c dependent on the furcating number of the hierarchy. In case of R > R c , the system is shown to exhibit as Ising-like critical point with the critical behaviour the same as in the pure case, while for R c the system belongs to another universality class. (author). 19 refs, 2 figs

  13. 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.

  14. Coupling between Spin and Charge Order Driven by Magnetic Field in Triangular Ising System LuFe2O4+δ

    Directory of Open Access Journals (Sweden)

    Lei Ding

    2018-02-01

    Full Text Available We present a study of the magnetic-field effect on spin correlations in the charge ordered triangular Ising system LuFe2O4+δ through single crystal neutron diffraction. In the absence of a magnetic field, the strong diffuse neutron scattering observed below the Neel temperature (TN = 240 K indicates that LuFe2O4+δ shows short-range, two-dimensional (2D correlations in the FeO5 triangular layers, characterized by the development of a magnetic scattering rod along the 1/3 1/3 L direction, persisting down to 5 K. We also found that on top of the 2D correlations, a long range ferromagnetic component associated with the propagation vector k1 = 0 sets in at around 240 K. On the other hand, an external magnetic field applied along the c-axis effectively favours a three-dimensional (3D spin correlation between the FeO5 bilayers evidenced by the increase of the intensity of satellite reflections with propagation vector k2 = (1/3, 1/3, 3/2. This magnetic modulation is identical to the charge ordered superstructure, highlighting the field-promoted coupling between the spin and charge degrees of freedom. Formation of the 3D spin correlations suppresses both the rod-type diffuse scattering and the k1 component. Simple symmetry-based arguments provide a natural explanation of the observed phenomenon and put forward a possible charge redistribution in the applied magnetic field.

  15. Zero-temperature renormalization method for quantum systems. I. Ising model in a transverse field in one dimension

    International Nuclear Information System (INIS)

    Jullien, R.; Pfeuty, P.; Fields, J.N.; Doniach, S.

    1978-01-01

    A zero-temperature real-space renormalization-group method is presented and applied to the quantum Ising model with a transverse field in one dimension. The transition between the low-field and high-field regimes is studied. Magnetization components, spin correlation functions, and critical exponents are derived and checked against the exact results. It is shown that increasing the size of the blocks in the iterative procedure yields more accurate results, especially for the critical ''magnetic'' exponents near the transition

  16. Research and Development of Rapid Design Systems for Aerospace Structure

    Science.gov (United States)

    Schaeffer, Harry G.

    1999-01-01

    This report describes the results of research activities associated with the development of rapid design systems for aerospace structures in support of the Intelligent Synthesis Environment (ISE). The specific subsystems investigated were the interface between model assembly and analysis; and, the high performance NASA GPS equation solver software system in the Windows NT environment on low cost high-performance PCs.

  17. Magnetic properties of a mixed spin-3/2 and spin-2 Ising ferrimagnetic system within the effective-field theory

    International Nuclear Information System (INIS)

    Deviren, Bayram; Kantar, Ersin; Keskin, Mustafa

    2010-01-01

    The magnetic properties of the ferrimagnetic mixed spin-3/2 and spin-2 Ising model with a crystal field in a longitudinal magnetic field on a honeycomb (δ = 3) and a square lattice (δ = 4) are studied by using the effective-field theory with correlations. The ground-state phase diagram of the model is obtained in a longitudinal magnetic field (h) for a single-ion potential or a crystal-field interaction (Δ) plane. We also investigate the thermal variations of the sublattice magnetization, and present the phase diagrams in the (Δ/|J|, k B T/|J|) plane. The susceptibility, internal energy, and specific heat of the system are numerically examined, and some interesting phenomena in these quantities are found due to the applied longitudinal magnetic field. Moreover, the system undergoes first- and second-order phase transitions; hence, the system has a tricritical point. The system also exhibits reentrant behaviors.

  18. Magnetic properties of a mixed spin-3/2 and spin-2 Ising ferrimagnetic system within the effective-field theory

    Energy Technology Data Exchange (ETDEWEB)

    Deviren, Bayram [Nevsehir University, Nevsehir (Turkmenistan); Kantar, Ersin; Keskin, Mustafa [Erciyes University, Kayseri (Turkmenistan)

    2010-06-15

    The magnetic properties of the ferrimagnetic mixed spin-3/2 and spin-2 Ising model with a crystal field in a longitudinal magnetic field on a honeycomb ({delta} = 3) and a square lattice ({delta} = 4) are studied by using the effective-field theory with correlations. The ground-state phase diagram of the model is obtained in a longitudinal magnetic field (h) for a single-ion potential or a crystal-field interaction ({Delta}) plane. We also investigate the thermal variations of the sublattice magnetization, and present the phase diagrams in the ({Delta}/|J|, k{sub B}T/|J|) plane. The susceptibility, internal energy, and specific heat of the system are numerically examined, and some interesting phenomena in these quantities are found due to the applied longitudinal magnetic field. Moreover, the system undergoes first- and second-order phase transitions; hence, the system has a tricritical point. The system also exhibits reentrant behaviors.

  19. Review of progresses on clinical applications of ion selective electrodes for electrolytic ion tests: from conventional ISEs to graphene-based ISEs

    Directory of Open Access Journals (Sweden)

    Rongguo Yan

    2016-10-01

    Full Text Available There exist several positively and negatively charged electrolytes or ions in human blood, urine, and other body fluids. Tests that measure the concentration of these ions in clinics are performed using a more affordable, portable, and disposable potentiometric sensing method with few sample volumes, which requires the use of ion-selective electrodes (ISEs and reference electrodes. This review summarily descriptively presents progressive developments and applications of ion selective electrodes in medical laboratory electrolytic ion tests, from conventional ISEs, solid-contact ISEs, carbon nanotube based ISEs, to graphene-based ISEs.

  20. Mean-Field Studies of a Mixed Spin-3/2 and Spin-2 and a Mixed Spin-3/2 and Spin-5/2 Ising System with Different Anisotropies

    International Nuclear Information System (INIS)

    Wei Guozhu; Miao Hailing

    2009-01-01

    The magnetic properties of a mixed spin-3/2 and spin-2 and a mixed spin-3/2 and spin-5/2 Ising ferromagnetic system with different anisotropies are studied by means of mean-field theory (MFT). The dependence of the phase diagram on single-ion anisotropy strengths is studied too. In the mixed spin-3/2 and spin-2 Ising model, besides the second-order phase transition, the first order-disorder phase transition and the tricritical line are found. In the mixed spin-3/2 and spin-5/2 Ising model, there is no first-order transition and tricritical line. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  1. Dynamic magnetic properties of the mixed spin-1 and spin-3/2 Ising system on a two-layer square lattice

    International Nuclear Information System (INIS)

    Temizer, Ümüt

    2014-01-01

    In this study, the dynamic critical behavior of the mixed spin-1 and spin-3/2 Ising system on a bilayer square lattice is studied by using the Glauber-type stochastic dynamics for both ferromagnetic/ferromagnetic (FM/FM) and antiferromagnetic/ferromagnetic (AFM/FM) interactions in the presence of a time-varying external magnetic field. The dynamic equations describing the time-dependencies of the average magnetizations are derived from the Master equation. The phases in the system are obtained by solving these dynamic equations. The temperature dependence of the dynamic magnetizations is investigated in order to characterize the nature (first- or second-order) of the dynamic phase transitions and to obtain the dynamic phase transition temperatures. The dynamic phase diagrams are constructed in seven different planes for both FM/FM and AFM/FM interactions and the effects of the related interaction parameters on the dynamic phase diagrams are examined. It is found that the dynamic phase diagrams display many dynamic critical points, such as tricritical point, triple point (TP), quadruple point (QP), double critical end point (B), multicritical point (A) and tetracritical point (M). Moreover, the reentrant behavior is observed for AFM/FM interaction in the system. - Highlights: • The mixed spin (1, 3/2) Ising system is studied on a two-layer square lattice. • The Glauber transition rates are employed to construct the dynamic equations. • The dynamic phase diagrams are presented in seven different planes. • The system displays many dynamic critical points. • The reentrant behavior is observed for AFM/FM interaction

  2. Phase diagrams of a nonequilibrium mixed spin-1/2 and spin-2 Ising ferrimagnetic system under a time-dependent oscillating magnetic field

    International Nuclear Information System (INIS)

    Keskin, M.; Canko, O.; Gueldal, S.

    2009-01-01

    We present phase diagrams for a nonequilibrium mixed spin-1/2 and spin-2 Ising ferrimagnetic system on a square lattice in the presence of a time dependent oscillating external magnetic field. We employ the Glauber transition rates to construct the mean-field dynamical equations. The time variation of the average magnetizations and the thermal behavior of the dynamic magnetizations are investigated, extensively. The nature (continuous or discontinuous) of the transitions is characterized by studying the thermal behaviors of the dynamic magnetizations. The dynamic phase transition points are obtained and the phase diagrams are presented in two different planes. Phase diagrams contain paramagnetic (p) and ferrimagnetic (i) phases, and one coexistence or mixed phase region, namely the i+p, that strongly depend on interaction parameters. The system exhibits the dynamic tricritical point and the reentrant behaviors.

  3. Phase diagrams of a nonequilibrium mixed spin-1/2 and spin-2 Ising ferrimagnetic system under a time-dependent oscillating magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Keskin, M., E-mail: keskin@erciyes.edu.t [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Canko, O. [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Gueldal, S. [Institute of Science, Erciyes University, 38039 Kayseri (Turkey)

    2009-12-14

    We present phase diagrams for a nonequilibrium mixed spin-1/2 and spin-2 Ising ferrimagnetic system on a square lattice in the presence of a time dependent oscillating external magnetic field. We employ the Glauber transition rates to construct the mean-field dynamical equations. The time variation of the average magnetizations and the thermal behavior of the dynamic magnetizations are investigated, extensively. The nature (continuous or discontinuous) of the transitions is characterized by studying the thermal behaviors of the dynamic magnetizations. The dynamic phase transition points are obtained and the phase diagrams are presented in two different planes. Phase diagrams contain paramagnetic (p) and ferrimagnetic (i) phases, and one coexistence or mixed phase region, namely the i+p, that strongly depend on interaction parameters. The system exhibits the dynamic tricritical point and the reentrant behaviors.

  4. 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.

  5. Integrated Support Environment (ISE) Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose:The Integrated Support Environment (ISE) Laboratory serves the fleet, in-service engineers, logisticians and program management offices by automatically and...

  6. Statistically interacting quasiparticles in Ising chains

    International Nuclear Information System (INIS)

    Lu Ping; Vanasse, Jared; Piecuch, Christopher; Karbach, Michael; Mueller, Gerhard

    2008-01-01

    The exclusion statistics of two complementary sets of quasiparticles, generated from opposite ends of the spectrum, are identified for Ising chains with spin s = 1/2, 1. In the s = 1/2 case the two sets are antiferromagnetic domain walls (solitons) and ferromagnetic domains (strings). In the s = 1 case they are soliton pairs and nested strings, respectively. The Ising model is equivalent to a system of two species of solitons for s = 1/2 and to a system of six species of soliton pairs for s = 1. Solitons exist on single bonds but soliton pairs may be spread across many bonds. The thermodynamics of a system of domains spanning up to M lattice sites is amenable to exact analysis and shown to become equivalent, in the limit M → ∞, to the thermodynamics of the s = 1/2 Ising chain. A relation is presented between the solitons in the Ising limit and the spinons in the XX limit of the s = 1/2 XXZ chain

  7. Power laws in Ising nanostripes

    International Nuclear Information System (INIS)

    Drzewinski, A.; Sznajd, J.; Szota, K.

    2005-01-01

    The results of high accuracy density-matrix renormalization-group calculations for infinite Ising stripes of finite widths 100 ≤ L ≤ 400 are presented. It is shown that in the presence of the small external magnetic field the infinite system critical power laws can be observed for L of order hundreds nm. The single power law describes the field dependence of the magnetization or the longitudinal correlation length only on the infinite system critical isotherm independently of the value of L. The approximate power law which describes how the magnetization varies with a distance from the infinite system critical point for several directions in the plane (temperature, external field) is also studied. (author)

  8. Magnetic hysteresis scaling in thulium: Implication of irreversibility-related scaling for soliton wall motion in an Ising system

    International Nuclear Information System (INIS)

    Kobayashi, Satoru

    2013-01-01

    We report low-field magnetic hysteresis scaling in thulium with strong uniaxial anisotropy. A power-law hysteresis scaling with an exponent of 1.13±0.02 is found between hysteresis loss and remanent flux density of minor loops in the low-temperature ferrimagnetic phase. This exponent value is slightly lower than 1.25–1.4 observed previously for ferromagnets and helimagnets. Unlike spiral and/or Bloch walls with a finite transition width, typical for Dy, Tb, and Ho with planar anisotropy, a soliton wall with a sudden phase shift between neighboring domains may dominate in Tm due to its Ising-like character. The observations imply the presence of universality class of hysteresis scaling that depends on the type of magnetic anisotropy. - Highlights: ► We observe magnetic hysteresis scaling in thulium with a power law exponent of 1.13. ► Irreversibility of soliton walls dominates owing to its strong uniaxial anisotropy. ► The exponent is lower than those for Bloch wall and spiral wall. ► The results imply the presence of universality class that depends on the wall type.

  9. Phase diagrams in mixed spin-3/2 and spin-2 Ising system with two alternative layers within the effective-field theory

    International Nuclear Information System (INIS)

    Deviren, Bayram; Polat, Yasin; Keskin, Mustafa

    2011-01-01

    The phase diagrams in the mixed spin-3/2 and spin-2 Ising system with two alternative layers on a honeycomb lattice are investigated and discussed by the use of the effective-field theory with correlations. The interaction of the nearest-neighbour spins of each layer is taken to be positive (ferromagnetic interaction) and the interaction of the adjacent spins of the nearest-neighbour layers is considered to be either positive or negative (ferromagnetic or anti-ferromagnetic interaction). The temperature dependence of the layer magnetizations of the system is examined to characterize the nature (continuous or discontinuous) of the phase transitions and obtain the phase transition temperatures. The system exhibits both second- and first-order phase transitions besides triple point (TP), critical end point (E), multicritical point (A), isolated critical point (C) and reentrant behaviour depending on the interaction parameters. We have also studied the temperature dependence of the total magnetization to find the compensation points, as well as to determine the type of behaviour, and N-type behaviour in Néel classification nomenclature existing in the system. The phase diagrams are constructed in eight different planes and it is found that the system also presents the compensation phenomena depending on the sign of the bilinear exchange interactions. (general)

  10. Dynamic magnetic behavior of the mixed spin (2, 5/2) Ising system with antiferromagnetic/antiferromagnetic interactions on a bilayer square lattice

    International Nuclear Information System (INIS)

    Ertaş Mehmet; Keskin Mustafa

    2013-01-01

    Using the mean-field theory and Glauber-type stochastic dynamics, we study the dynamic magnetic properties of the mixed spin (2, 5/2) Ising system for the antiferromagnetic/antiferromagnetic (AFM/AFM) interactions on the bilayer square lattice under a time varying (sinusoidal) magnetic field. The time dependence of average magnetizations and the thermal variation of the dynamic magnetizations are examined to calculate the dynamic phase diagrams. The dynamic phase diagrams are presented in the reduced temperature and magnetic field amplitude plane and the effects of interlayer coupling interaction on the critical behavior of the system are investigated. We also investigate the influence of the frequency and find that the system displays richer dynamic critical behavior for higher values of frequency than that of the lower values of it. We perform a comparison with the ferromagnetic/ferromagnetic (FM/FM) and AFM/FM interactions in order to see the effects of AFM/AFM interaction and observe that the system displays richer and more interesting dynamic critical behaviors for the AFM/AFM interaction than those for the FM/FM and AFM/FM interactions. (general)

  11. Physics and financial economics (1776-2014): puzzles, Ising and agent-based models

    Science.gov (United States)

    Sornette, Didier

    2014-06-01

    This short review presents a selected history of the mutual fertilization between physics and economics—from Isaac Newton and Adam Smith to the present. The fundamentally different perspectives embraced in theories developed in financial economics compared with physics are dissected with the examples of the volatility smile and of the excess volatility puzzle. The role of the Ising model of phase transitions to model social and financial systems is reviewed, with the concepts of random utilities and the logit model as the analog of the Boltzmann factor in statistical physics. Recent extensions in terms of quantum decision theory are also covered. A wealth of models are discussed briefly that build on the Ising model and generalize it to account for the many stylized facts of financial markets. A summary of the relevance of the Ising model and its extensions is provided to account for financial bubbles and crashes. The review would be incomplete if it did not cover the dynamical field of agent-based models (ABMs), also known as computational economic models, of which the Ising-type models are just special ABM implementations. We formulate the ‘Emerging Intelligence Market Hypothesis’ to reconcile the pervasive presence of ‘noise traders’ with the near efficiency of financial markets. Finally, we note that evolutionary biology, more than physics, is now playing a growing role to inspire models of financial markets.

  12. Physics and financial economics (1776–2014): puzzles, Ising and agent-based models

    International Nuclear Information System (INIS)

    Sornette, Didier

    2014-01-01

    This short review presents a selected history of the mutual fertilization between physics and economics—from Isaac Newton and Adam Smith to the present. The fundamentally different perspectives embraced in theories developed in financial economics compared with physics are dissected with the examples of the volatility smile and of the excess volatility puzzle. The role of the Ising model of phase transitions to model social and financial systems is reviewed, with the concepts of random utilities and the logit model as the analog of the Boltzmann factor in statistical physics. Recent extensions in terms of quantum decision theory are also covered. A wealth of models are discussed briefly that build on the Ising model and generalize it to account for the many stylized facts of financial markets. A summary of the relevance of the Ising model and its extensions is provided to account for financial bubbles and crashes. The review would be incomplete if it did not cover the dynamical field of agent-based models (ABMs), also known as computational economic models, of which the Ising-type models are just special ABM implementations. We formulate the ‘Emerging Intelligence Market Hypothesis’ to reconcile the pervasive presence of ‘noise traders’ with the near efficiency of financial markets. Finally, we note that evolutionary biology, more than physics, is now playing a growing role to inspire models of financial markets. (key issues reviews)

  13. Physics and financial economics (1776-2014): puzzles, Ising and agent-based models.

    Science.gov (United States)

    Sornette, Didier

    2014-06-01

    This short review presents a selected history of the mutual fertilization between physics and economics--from Isaac Newton and Adam Smith to the present. The fundamentally different perspectives embraced in theories developed in financial economics compared with physics are dissected with the examples of the volatility smile and of the excess volatility puzzle. The role of the Ising model of phase transitions to model social and financial systems is reviewed, with the concepts of random utilities and the logit model as the analog of the Boltzmann factor in statistical physics. Recent extensions in terms of quantum decision theory are also covered. A wealth of models are discussed briefly that build on the Ising model and generalize it to account for the many stylized facts of financial markets. A summary of the relevance of the Ising model and its extensions is provided to account for financial bubbles and crashes. The review would be incomplete if it did not cover the dynamical field of agent-based models (ABMs), also known as computational economic models, of which the Ising-type models are just special ABM implementations. We formulate the 'Emerging Intelligence Market Hypothesis' to reconcile the pervasive presence of 'noise traders' with the near efficiency of financial markets. Finally, we note that evolutionary biology, more than physics, is now playing a growing role to inspire models of financial markets.

  14. Hyperscaling breakdown and Ising spin glasses: The Binder cumulant

    Science.gov (United States)

    Lundow, P. H.; Campbell, I. A.

    2018-02-01

    Among the Renormalization Group Theory scaling rules relating critical exponents, there are hyperscaling rules involving the dimension of the system. It is well known that in Ising models hyperscaling breaks down above the upper critical dimension. It was shown by Schwartz (1991) that the standard Josephson hyperscaling rule can also break down in Ising systems with quenched random interactions. A related Renormalization Group Theory hyperscaling rule links the critical exponents for the normalized Binder cumulant and the correlation length in the thermodynamic limit. An appropriate scaling approach for analyzing measurements from criticality to infinite temperature is first outlined. Numerical data on the scaling of the normalized correlation length and the normalized Binder cumulant are shown for the canonical Ising ferromagnet model in dimension three where hyperscaling holds, for the Ising ferromagnet in dimension five (so above the upper critical dimension) where hyperscaling breaks down, and then for Ising spin glass models in dimension three where the quenched interactions are random. For the Ising spin glasses there is a breakdown of the normalized Binder cumulant hyperscaling relation in the thermodynamic limit regime, with a return to size independent Binder cumulant values in the finite-size scaling regime around the critical region.

  15. The square Ising model with second-neighbor interactions and the Ising chain in a transverse field

    International Nuclear Information System (INIS)

    Grynberg, M.D.; Tanatar, B.

    1991-06-01

    We consider the thermal and critical behaviour of the square Ising lattice with frustrated first - and second-neighbor interactions. A low-temperature domain wall analysis including kinks and dislocations shows that there is a close relation between this classical model and the Hamiltonian of an Ising chain in a transverse field provided that the ratio of the next-nearest to nearest-neighbor coupling, is close to 1/2. Due to the field inversion symmetry of the Ising chain Hamiltonian, the thermal properties of the classical system are symmetrical with respect to this coupling ratio. In the neighborhood of this regime critical exponents of the model turn out to belong to the Ising universality class. Our results are compared with previous Monte Carlo simulations. (author). 23 refs, 6 figs

  16. Thue-Morse quantum Ising model

    International Nuclear Information System (INIS)

    Doria, M.M.; Nori, F.; Satija, I.I.

    1989-01-01

    We study the one-dimensional quantum Ising model in a transverse magnetic field where the exchange couplings are ordered according to the Thue-Morse (TM) sequence. At zero temperature, this model is equivalent to a two-dimensional classical Ising model in a magnetic field with TM aperiodicity along one direction. We compute the order parameter (magnetization) of the chain and the scaling behavior of the energy spectrum when the system undergoes a phase transition. Analogous to the quasiperiodic (QP) quantum Ising chain, the onset of long-range order is signaled by a nonanaliticity in the exponent δ which describes the scaling of the total bandwidth with the size of the chain. The critical spin-coupling can be computed analytically and it is found to be lower than the QP case. Furthermore, the energy bands are found to be narrower than the corresponding QP chain. The former and latter results are consistent with the fact that the present structure has a degree of ordering intermediate between QP and random

  17. Quantum Ising chains with boundary fields

    International Nuclear Information System (INIS)

    Campostrini, Massimo; Vicari, Ettore; Pelissetto, Andrea

    2015-01-01

    We present a detailed study of the finite one-dimensional quantum Ising chain in a transverse field in the presence of boundary magnetic fields coupled with the order-parameter spin operator. We consider two magnetic fields located at the boundaries of the chain that have the same strength and that are aligned in the same or in the opposite direction. We derive analytic expressions for the gap in all phases for large values of the chain length L, as a function of the boundary field strength. We also investigate the behaviour of the chain in the quantum ferromagnetic phase for oppositely aligned fields, focusing on the magnet-to-kink transition that occurs at a finite value of the magnetic field strength. At this transition we compute analytically the finite-size crossover functions for the gap, the magnetisation profile, the two-point correlation function, and the density of fermionic modes. As the magnet-to-kink transition is equivalent to the wetting transition in two-dimensional classical Ising models, our results provide new analytic predictions for the finite-size behaviour of Ising systems in a strip geometry at this transition. (paper)

  18. Fermions as generalized Ising models

    Directory of Open Access Journals (Sweden)

    C. Wetterich

    2017-04-01

    Full Text Available We establish a general map between Grassmann functionals for fermions and probability or weight distributions for Ising spins. The equivalence between the two formulations is based on identical transfer matrices and expectation values of products of observables. The map preserves locality properties and can be realized for arbitrary dimensions. We present a simple example where a quantum field theory for free massless Dirac fermions in two-dimensional Minkowski space is represented by an asymmetric Ising model on a euclidean square lattice.

  19. Crossover from mean field to three-dimensional ising critical behavior in a three-component microemulsion system

    DEFF Research Database (Denmark)

    Seto, H.; Schwahn, D.; Nagao, M.

    1996-01-01

    Critical density fluctuations of water droplets in an oil-rich three-component microemulsion system have been studied by small-angle neutron scattering as a function of temperature near and far from the boundary of phase decomposition. The observed data in the one-phase region are well described...

  20. Critical behavior of AC antiferromagnetic and ferromagnetic susceptibilities of a spin-1/2 metamagnetic Ising system

    International Nuclear Information System (INIS)

    Gulpinar, Gul; Vatansever, Erol

    2012-01-01

    In this study, the temperature variations of the equilibrium and the non-equilibrium antiferromagnetic and ferromagnetic susceptibilities of a metamagnetic system are examined near the critical point. The kinetic equations describing the time dependencies of the total and staggered magnetizations are derived by utilizing linear response theory. In order to obtain dynamic magnetic relaxation behavior of the system, the stationary solutions of the kinetic equations in existence of sinusoidal staggered and physical external magnetic fields are performed. In addition, the static and dynamical mean field critical exponents are calculated in order to formulate the critical behavior of antiferromagnetic and ferromagnetic magnetic response of a metamagnetic system. Finally, a comparison of the findings of this study with previous theoretical and experimental studies is represented and it is shown that a good agreement is found with our results. - Highlights: ► Staggered dynamic susceptibility diverges as T→T N in the low frequency region. ► Dynamic total susceptibility exhibits a finite jump discontinuity as T→T N while wτ 2 ⪡1. ► The slope of the staggered magnetic dispersion curve chances in sign as T→T N .

  1. A coherent Ising machine for 2000-node optimization problems

    Science.gov (United States)

    Inagaki, Takahiro; Haribara, Yoshitaka; Igarashi, Koji; Sonobe, Tomohiro; Tamate, Shuhei; Honjo, Toshimori; Marandi, Alireza; McMahon, Peter L.; Umeki, Takeshi; Enbutsu, Koji; Tadanaga, Osamu; Takenouchi, Hirokazu; Aihara, Kazuyuki; Kawarabayashi, Ken-ichi; Inoue, Kyo; Utsunomiya, Shoko; Takesue, Hiroki

    2016-11-01

    The analysis and optimization of complex systems can be reduced to mathematical problems collectively known as combinatorial optimization. Many such problems can be mapped onto ground-state search problems of the Ising model, and various artificial spin systems are now emerging as promising approaches. However, physical Ising machines have suffered from limited numbers of spin-spin couplings because of implementations based on localized spins, resulting in severe scalability problems. We report a 2000-spin network with all-to-all spin-spin couplings. Using a measurement and feedback scheme, we coupled time-multiplexed degenerate optical parametric oscillators to implement maximum cut problems on arbitrary graph topologies with up to 2000 nodes. Our coherent Ising machine outperformed simulated annealing in terms of accuracy and computation time for a 2000-node complete graph.

  2. Exact sampling hardness of Ising spin models

    Science.gov (United States)

    Fefferman, B.; Foss-Feig, M.; Gorshkov, A. V.

    2017-09-01

    We study the complexity of classically sampling from the output distribution of an Ising spin model, which can be implemented naturally in a variety of atomic, molecular, and optical systems. In particular, we construct a specific example of an Ising Hamiltonian that, after time evolution starting from a trivial initial state, produces a particular output configuration with probability very nearly proportional to the square of the permanent of a matrix with arbitrary integer entries. In a similar spirit to boson sampling, the ability to sample classically from the probability distribution induced by time evolution under this Hamiltonian would imply unlikely complexity theoretic consequences, suggesting that the dynamics of such a spin model cannot be efficiently simulated with a classical computer. Physical Ising spin systems capable of achieving problem-size instances (i.e., qubit numbers) large enough so that classical sampling of the output distribution is classically difficult in practice may be achievable in the near future. Unlike boson sampling, our current results only imply hardness of exact classical sampling, leaving open the important question of whether a much stronger approximate-sampling hardness result holds in this context. The latter is most likely necessary to enable a convincing experimental demonstration of quantum supremacy. As referenced in a recent paper [A. Bouland, L. Mancinska, and X. Zhang, in Proceedings of the 31st Conference on Computational Complexity (CCC 2016), Leibniz International Proceedings in Informatics (Schloss Dagstuhl-Leibniz-Zentrum für Informatik, Dagstuhl, 2016)], our result completes the sampling hardness classification of two-qubit commuting Hamiltonians.

  3. Quasi-realistic distribution of interaction fields leading to a variant of Ising spin glass model

    International Nuclear Information System (INIS)

    Tanasa, Radu; Enachescu, Cristian; Stancu, Alexandru; Linares, Jorge; Varret, Francois

    2004-01-01

    The distribution of interaction fields of an Ising-like system, obtained by Monte Carlo entropic sampling is used for modeling the hysteretic behavior of patterned media made of magnetic particles with a common anisotropy axis; a variant of the canonical Edwards-Anderson Ising spin glass model is introduced

  4. Phi4 lattice field theory as an asymptotic expansion about the Ising limit

    International Nuclear Information System (INIS)

    Caginalp, G.

    1980-01-01

    For a d-dimensional phi 4 lattice field theory consisting of N spins, an asymptotic expansion of expectations about the Ising limit is established in inverse powers of the bare coupling constant lambda. In the thermodynamic limit (N→infinity), the expansion is expected to be valid in the noncritical region of the Ising system

  5. Quantum simulation of transverse Ising models with Rydberg atoms

    Science.gov (United States)

    Schauss, Peter

    2018-04-01

    Quantum Ising models are canonical models for the study of quantum phase transitions (Sachdev 1999 Quantum Phase Transitions (Cambridge: Cambridge University Press)) and are the underlying concept for many analogue quantum computing and quantum annealing ideas (Tanaka et al Quantum Spin Glasses, Annealing and Computation (Cambridge: Cambridge University Press)). Here we focus on the implementation of finite-range interacting Ising spin models, which are barely tractable numerically. Recent experiments with cold atoms have reached the interaction-dominated regime in quantum Ising magnets via optical coupling of trapped neutral atoms to Rydberg states. This approach allows for the tunability of all relevant terms in an Ising spin Hamiltonian with 1/{r}6 interactions in transverse and longitudinal fields. This review summarizes the recent progress of these implementations in Rydberg lattices with site-resolved detection. Strong correlations in quantum Ising models have been observed in several experiments, starting from a single excitation in the superatom regime up to the point of crystallization. The rapid progress in this field makes spin systems based on Rydberg atoms a promising platform for quantum simulation because of the unmatched flexibility and strength of interactions combined with high control and good isolation from the environment.

  6. Entrepreneurial Leapfrogging in the Context of ISE

    DEFF Research Database (Denmark)

    Li, Peter

    2013-01-01

    We know little regarding the underlying contexts and mechanisms for disruptive innovation initiated by the entrepreneurial firms in the emerging economies. Further, there is limited knowledge about the contexts and mechanisms for global latecomers to catch up with and leapfrog global early......-movers. The cross-fertilization between such two research streams provides a great opportunity to shed light on their link toward an interdisciplinary domain of international strategic entrepreneurship (ISE). This article will develop an integrative typology of global innovations as well as a dynamic model...

  7. Simulation of glioblastoma multiforme (GBM) tumor cells using ising model on the Creutz Cellular Automaton

    Science.gov (United States)

    Züleyha, Artuç; Ziya, Merdan; Selçuk, Yeşiltaş; Kemal, Öztürk M.; Mesut, Tez

    2017-11-01

    Computational models for tumors have difficulties due to complexity of tumor nature and capacities of computational tools, however, these models provide visions to understand interactions between tumor and its micro environment. Moreover computational models have potential to develop strategies for individualized treatments for cancer. To observe a solid brain tumor, glioblastoma multiforme (GBM), we present a two dimensional Ising Model applied on Creutz cellular automaton (CCA). The aim of this study is to analyze avascular spherical solid tumor growth, considering transitions between non tumor cells and cancer cells are like phase transitions in physical system. Ising model on CCA algorithm provides a deterministic approach with discrete time steps and local interactions in position space to view tumor growth as a function of time. Our simulation results are given for fixed tumor radius and they are compatible with theoretical and clinic data.

  8. Single-file water as a one-dimensional Ising model

    Energy Technology Data Exchange (ETDEWEB)

    Koefinger, Juergen [Laboratory of Chemical Physics, Bldg 5, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892 (United States); Dellago, Christoph, E-mail: koefingerj@mail.nih.go [Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna (Austria)

    2010-09-15

    We show that single-file water in nanopores can be viewed as a one-dimensional (1D) Ising model, and we investigate, on the basis of this, the static dielectric response of a chain of hydrogen-bonded water molecules to an external field. To achieve this, we use a recently developed dipole lattice model that accurately captures the free energetics of nanopore water. In this model, the total energy of the system can be expressed as the sum of the effective interactions of chain ends and orientational defects. Neglecting these interactions, we essentially obtain the 1D Ising model, which allows us to derive analytical expressions for the free energy as a function of the total dipole moment and for the dielectric susceptibility. Our expressions, which agree very well with simulation results, provide the basis for the interpretation of future dielectric spectroscopy experiments on water-filled nanopore membranes.

  9. An Ising spin state explanation for financial asset allocation

    Science.gov (United States)

    Horvath, Philip A.; Roos, Kelly R.; Sinha, Amit

    2016-03-01

    We build on the developments in the application of statistical mechanics, notably the identity of the spin degree of freedom in the Ising model, to explain asset price dynamics in financial markets with a representative agent. Specifically, we consider the value of an individual spin to represent the proportional holdings in various assets. We use partial moment arguments to identify asymmetric reactions to information and develop an extension of a plunging and dumping model. This unique identification of the spin is a relaxation of the conventional discrete state limitation on an Ising spin to accommodate a new archetype in Ising model-finance applications wherein spin states may take on continuous values, and may evolve in time continuously, or discretely, depending on the values of the partial moments.

  10. Dynamics of the Random Field Ising Model

    Science.gov (United States)

    Xu, Jian

    The Random Field Ising Model (RFIM) is a general tool to study disordered systems. Crackling noise is generated when disordered systems are driven by external forces, spanning a broad range of sizes. Systems with different microscopic structures such as disordered mag- nets and Earth's crust have been studied under the RFIM. In this thesis, we investigated the domain dynamics and critical behavior in two dipole-coupled Ising ferromagnets Nd2Fe14B and LiHoxY 1-xF4. With Tc well above room temperature, Nd2Fe14B has shown reversible disorder when exposed to an external transverse field and crosses between two universality classes in the strong and weak disorder limits. Besides tunable disorder, LiHoxY1-xF4 has shown quantum tunneling effects arising from quantum fluctuations, providing another mechanism for domain reversal. Universality within and beyond power law dependence on avalanche size and energy were studied in LiHo0.65Y0.35 F4.

  11. Contingency plans for the ISEE-3 libration-point mission

    Science.gov (United States)

    Dunham, D. W.

    1979-01-01

    During the planning stage of the International Sun-Earth Explorer-3 (ISEE-3) mission, a recovery strategy was developed in case the Delta rocket underperformed during the launch phase. If a large underburn had occurred, the ISEE-3 spacecraft would have been allowed to complete one revolution of its highly elliptical earth orbit. The recovery plan called for a maneuver near perigee to increase the energy of the off-nominal orbit; a relatively small second maneuver would then insert the spacecraft into a new transfer trajectory toward the desired halo orbit target, and a third maneuver would place the spacecraft in the halo orbit. Results of the study showed that a large range of underburns could be corrected for a total nominal velocity deviation cost within the ISEE-3 fuel budget.

  12. Quantum quench in an atomic one-dimensional Ising chain.

    Science.gov (United States)

    Meinert, F; Mark, M J; Kirilov, E; Lauber, K; Weinmann, P; Daley, A J; Nägerl, H-C

    2013-08-02

    We study nonequilibrium dynamics for an ensemble of tilted one-dimensional atomic Bose-Hubbard chains after a sudden quench to the vicinity of the transition point of the Ising paramagnetic to antiferromagnetic quantum phase transition. The quench results in coherent oscillations for the orientation of effective Ising spins, detected via oscillations in the number of doubly occupied lattice sites. We characterize the quench by varying the system parameters. We report significant modification of the tunneling rate induced by interactions and show clear evidence for collective effects in the oscillatory response.

  13. Dynamics of the directed Ising chain

    International Nuclear Information System (INIS)

    Godrèche, Claude

    2011-01-01

    The study by Glauber of the time-dependent statistics of the Ising chain is extended to the case where each spin is influenced unequally by its nearest neighbours. The asymmetry of the dynamics implies the failure of the detailed balance condition. The functional form of the rate at which an individual spin changes its state is constrained by the global balance condition with respect to the equilibrium measure of the Ising chain. The local magnetization, the equal-time and two-time correlation functions and the linear response to an external magnetic field obey linear equations which are solved explicitly. The behaviour of these quantities and the relation between the correlation and response functions are analysed both in the stationary state and in the zero-temperature scaling regime. In the stationary state, a transition between two behaviours of the correlation function occurs when the amplitude of the asymmetry crosses a critical value, with the consequence that the limit fluctuation-dissipation ratio decays continuously from the value 1, for the equilibrium state in the absence of asymmetry, to 0 for this critical value. At zero temperature, under asymmetric dynamics, the system loses its critical character, yet keeping many of the characteristic features of a coarsening system

  14. Applications of ISES for the atmospheric sciences

    Science.gov (United States)

    Hoell, James M., Jr.

    1990-01-01

    The proposed Information Sciences Experiment System (ISES) will offer the opportunity for real-time access to measurements acquired aboard the Earth Observation System (Eos) satellite. These measurements can then be transmitted to remotely located ground based stations. The application of such measurements to issues related to atmospheric science which was presented to a workshop convened to review possible application of the ISES in earth sciences is summarized. The proposed protocol for Eos instruments requires that measurement results be available in a central data archive within 72 hours of acquiring data. Such a turnaround of raw satellite data to the final product will clearly enhance the timeliness of the results. Compared to the time that results from many current satellite programs, the 72 hour turnaround may be considered real time. Examples are discussed showing how real-time measurements from one or more of the proposed Eos instruments could have been applied to the study of certain issues important to global atmospheric chemistry. Each of the examples discussed is based upon a field mission conducted during the past five years. Each of these examples will emphasize how real-time data could have been used to alter the course of a field experiment, thereby enhancing the scientific output. For the examples, brief overviews of the scientific rationale and objectives, the region of operation, the measurements aboard the aircraft, and finally how one or more of the proposed Eos instruments could have provided data to enhance the productivity of the mission are discussed.

  15. The dynamics of the Frustrated Ising Lattice Gas

    International Nuclear Information System (INIS)

    Arenzon, J.J.; Stariolo, D.A.; Ricci-Tersenghi, F.

    2000-04-01

    The dynamical properties of a three dimensional model glass, the Frustrated Ising Lattice Gas (FILG) are studied by Monte Carlo simulations. We present results of compression experiments, where the chemical potential is either slowly or abruptly changed, as well as simulations at constant density. One-time quantities like density and two-times ones as correlations, responses and mean square displacements are measured, and the departure from equilibrium clearly characterized. The aging scenario, particularly in the case of the density autocorrelations, is reminiscent of spin glass phenomenology with violations of the fluctuation-dissipation theorem, typical of systems with one replica symmetry breaking. The FILG, as a valid on-lattice model of structural glasses, can be described with tools developed in spin glass theory and, being a finite dimensional model, can open the way for a systematic study of activated processes in glasses. (author)

  16. The order parameter and susceptibility of the 3D Ising-like system in an external field near the phase transition point

    Directory of Open Access Journals (Sweden)

    M.P. Kozlovskii

    2010-01-01

    Full Text Available The present work is devoted to the investigation of the 3D Ising-like model in the presence of an external field in the vicinity of critical point. The method of collective variables is used. General expressions for the order parameter and susceptibility are calculated as functions of temperature and the external field as well as scaling functions of that are explicitly obtained. The results are compared with the ones obtained within the framework of parametric representation of the equation of state and Monte Carlo simulations. New expression for the exit point from critical regime of the order parameter fluctuations is proposed and used for the calculation.

  17. Disorder Identification in Hysteresis Data: Recognition Analysis of the Random-Bond-Random-Field Ising Model

    International Nuclear Information System (INIS)

    Ovchinnikov, O. S.; Jesse, S.; Kalinin, S. V.; Bintacchit, P.; Trolier-McKinstry, S.

    2009-01-01

    An approach for the direct identification of disorder type and strength in physical systems based on recognition analysis of hysteresis loop shape is developed. A large number of theoretical examples uniformly distributed in the parameter space of the system is generated and is decorrelated using principal component analysis (PCA). The PCA components are used to train a feed-forward neural network using the model parameters as targets. The trained network is used to analyze hysteresis loops for the investigated system. The approach is demonstrated using a 2D random-bond-random-field Ising model, and polarization switching in polycrystalline ferroelectric capacitors.

  18. Ising models and soliton equations

    International Nuclear Information System (INIS)

    Perk, J.H.H.; Au-Yang, H.

    1985-01-01

    Several new results for the critical point of correlation functions of the Hirota equation are derived within the two-dimensional Ising model. The recent success of the conformal-invariance approach in the determination of a critical two-spin correration function is analyzed. The two-spin correlation function is predicted to be rotationally invariant and to decay with a power law in this approach. In the approach suggested here systematic corrections due to the underlying lattice breaking the rotational invariance are obtained

  19. Ising ferromagnet: zero-temperature dynamic evolution

    International Nuclear Information System (INIS)

    Oliveira, P M C de; Newman, C M; Sidoravicious, V; Stein, D L

    2006-01-01

    The dynamic evolution at zero temperature of a uniform Ising ferromagnet on a square lattice is followed by Monte Carlo computer simulations. The system always eventually reaches a final, absorbing state, which sometimes coincides with a ground state (all spins parallel), and sometimes does not (parallel stripes of spins up and down). We initiate here the numerical study of 'chaotic time dependence' (CTD) by seeing how much information about the final state is predictable from the randomly generated quenched initial state. CTD was originally proposed to explain how nonequilibrium spin glasses could manifest an equilibrium pure state structure, but in simpler systems such as homogeneous ferromagnets it is closely related to long-term predictability and our results suggest that CTD might indeed occur in the infinite volume limit

  20. The Relationship between Macroeconomic Variables and ISE Industry Index

    Directory of Open Access Journals (Sweden)

    Ahmet Ozcan

    2012-01-01

    Full Text Available In this study, the relationship between macroeconomic variables and Istanbul Stock Exchange (ISE industry index is examined. Over the past years, numerous studies have analyzed these relationships and the different results obtained from these studies have motivated further research. The relationship between stock exchange index and macroeconomic variables has been well documented for the developed markets. However, there are few studies regarding the relationship between macroeconomic variables and stock exchange index for the developing markets. Thus, this paper seeks to address the question of whether macroeconomic variables have a significant relationship with ISE industry index using monthly data for the period from 2003 to 2010. The selected macroeconomic variables for the study include interest rates, consumer price index, money supply, exchange rate, gold prices, oil prices, current account deficit and export volume. The Johansen’s cointegration test is utilized to determine the impact of selected macroeconomic variables on ISE industry index. The result of the Johansen’s cointegration shows that macroeconomic variables exhibit a long run equilibrium relationship with the ISE industry index.

  1. Testing Lorentz Invariance Emergence in the Ising Model using Monte Carlo simulations

    CERN Document Server

    Dias Astros, Maria Isabel

    2017-01-01

    In the context of the Lorentz invariance as an emergent phenomenon at low energy scales to study quantum gravity a system composed by two 3D interacting Ising models (one with an anisotropy in one direction) was proposed. Two Monte Carlo simulations were run: one for the 2D Ising model and one for the target model. In both cases the observables (energy, magnetization, heat capacity and magnetic susceptibility) were computed for different lattice sizes and a Binder cumulant introduced in order to estimate the critical temperature of the systems. Moreover, the correlation function was calculated for the 2D Ising model.

  2. Integrals of the Ising class

    International Nuclear Information System (INIS)

    Bailey, D H; Borwein, J M; Crandall, R E

    2006-01-01

    From an experimental-mathematical perspective we analyse 'Ising-class' integrals. These are structurally related n-dimensional integrals we call C n , D n , E n , where D n is a magnetic susceptibility integral central to the Ising theory of solid-state physics. We first analyse C n := 4/(n factorial) ∫ 0 ∞ ... ∫ 0 ∞ 1/(Σ j=1 n (u j + 1/u j )) 2 du 1 /u 1 ... du n /u n . We had conjectured-on the basis of extreme-precision numerical quadrature-that C n has a finite large-n limit, namely C ∞ = 2 e -2γ , with γ being the Euler constant. On such a numerological clue we are able to prove the conjecture. We then show that integrals D n and E n both decay exponentially with n, in a certain rigorous sense. While C n , D n remain unresolved for n ≥ 5, we were able to conjecture a closed form for E 5 . Our experimental results involved extreme-precision, multidimensional quadrature on intricate integrands; thus, a highly parallel computation was required

  3. Proceedings of the ISES Millennium Solar Forum 2000. 1. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Estrada, Claudio A. [ed.

    2000-07-01

    The ISES Millennium Solar Forum 2000 was organized by the Association Nacional de Energia Solar (ANES) of Mexico, and the International Solar Energy Society (ISES), in collaboration with other national and international organizations from 17 to 22 of September, 2000 in Mexico City. The Scientific-Technical Conference forms the core of this forum. This comprises of 167 papers, which were presented orally and form part of the proceedings. The papers represent the results of research and technological development effort in Renewable Energy reported by professionals and students of 22 countries. Of course, a major component is from Mexico and Latin America. Here you will find useful information on the advances in different fields of Renewable Energy. [Spanish] La Asociacion Nacional de Energia Solar A.C. (ANES) y la International Solar Society (ISES), apoyadas por organizaciones nacionales e internacionales, comprometidas con la promocion de las energias renovables organizaron el ISES Millennium Solar Forum 2000, los dias 17 a 22 de septiembre del 2000 en la Ciudad de Mexico. Como parte medular de este foro se organizo la reunion cientifico-tecnica, en donde se presentaron 167 trabajos, la mayoria de los cuales se incluyen en esta memoria. Estos trabajos representan el esfuerzo en investigacion y desarrollo tecnologico de estudiantes y profesionales de mas de 22 paises, la mayoria de Mexico y America Latina. En esta memoria se encuentran los avances mas relevantes en las distintas areas de especializacion de las energias renovables.

  4. Inverse Ising problem in continuous time: A latent variable approach

    Science.gov (United States)

    Donner, Christian; Opper, Manfred

    2017-12-01

    We consider the inverse Ising problem: the inference of network couplings from observed spin trajectories for a model with continuous time Glauber dynamics. By introducing two sets of auxiliary latent random variables we render the likelihood into a form which allows for simple iterative inference algorithms with analytical updates. The variables are (1) Poisson variables to linearize an exponential term which is typical for point process likelihoods and (2) Pólya-Gamma variables, which make the likelihood quadratic in the coupling parameters. Using the augmented likelihood, we derive an expectation-maximization (EM) algorithm to obtain the maximum likelihood estimate of network parameters. Using a third set of latent variables we extend the EM algorithm to sparse couplings via L1 regularization. Finally, we develop an efficient approximate Bayesian inference algorithm using a variational approach. We demonstrate the performance of our algorithms on data simulated from an Ising model. For data which are simulated from a more biologically plausible network with spiking neurons, we show that the Ising model captures well the low order statistics of the data and how the Ising couplings are related to the underlying synaptic structure of the simulated network.

  5. Ising model for neural data

    DEFF Research Database (Denmark)

    Roudi, Yasser; Tyrcha, Joanna; Hertz, John

    2009-01-01

    (dansk abstrakt findes ikke) We study pairwise Ising models for describing the statistics of multi-neuron spike trains, using data from a simulated cortical network. We explore efficient ways of finding the optimal couplings in these models and examine their statistical properties. To do this, we...... extract the optimal couplings for subsets of size up to $200$ neurons, essentially exactly, using Boltzmann learning. We then study the quality of several approximate methods for finding the couplings by comparing their results with those found from Boltzmann learning. Two of these methods -- inversion...... of the Thouless-Anderson-Palmer equations and an approximation proposed by Sessak and Monasson -- are remarkably accurate. Using these approximations for larger subsets of neurons, we find that extracting couplings using data from a subset smaller than the full network tends systematically to overestimate...

  6. Multiple Time Series Ising Model for Financial Market Simulations

    International Nuclear Information System (INIS)

    Takaishi, Tetsuya

    2015-01-01

    In this paper we propose an Ising model which simulates multiple financial time series. Our model introduces the interaction which couples to spins of other systems. Simulations from our model show that time series exhibit the volatility clustering that is often observed in the real financial markets. Furthermore we also find non-zero cross correlations between the volatilities from our model. Thus our model can simulate stock markets where volatilities of stocks are mutually correlated

  7. Ising model for packet routing control

    International Nuclear Information System (INIS)

    Horiguchi, Tsuyoshi; Takahashi, Hideyuki; Hayashi, Keisuke; Yamaguchi, Chiaki

    2004-01-01

    For packet routing control in computer networks, we propose an Ising model which is defined in order to express competition among a queue length and a distance from a node with a packet to its destination node. By introducing a dynamics for a mean-field value of an Ising spin, we show by computer simulations that effective control of packet routing through priority links is possible

  8. Ising formulations of many NP problems

    OpenAIRE

    Lucas, Andrew

    2013-01-01

    We provide Ising formulations for many NP-complete and NP-hard problems, including all of Karp's 21 NP-complete problems. This collects and extends mappings to the Ising model from partitioning, covering and satisfiability. In each case, the required number of spins is at most cubic in the size of the problem. This work may be useful in designing adiabatic quantum optimization algorithms.

  9. Ising formulations of many NP problems

    Directory of Open Access Journals (Sweden)

    Andrew eLucas

    2014-02-01

    Full Text Available We provide Ising formulations for many NP-complete and NP-hard problems, including all of Karp's 21 NP-complete problems. This collects and extends mappings to the Ising model from partitioning, covering and satisfiability. In each case, the required number of spins is at most cubic in the size of the problem. This work may be useful in designing adiabatic quantum optimization algorithms.

  10. 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.)

  11. Computational Analysis of 3D Ising Model Using Metropolis Algorithms

    International Nuclear Information System (INIS)

    Sonsin, A F; Cortes, M R; Nunes, D R; Gomes, J V; Costa, R S

    2015-01-01

    We simulate the Ising Model with the Monte Carlo method and use the algorithms of Metropolis to update the distribution of spins. We found that, in the specific case of the three-dimensional Ising Model, methods of Metropolis are efficient. Studying the system near the point of phase transition, we observe that the magnetization goes to zero. In our simulations we analyzed the behavior of the magnetization and magnetic susceptibility to verify the phase transition in a paramagnetic to ferromagnetic material. The behavior of the magnetization and of the magnetic susceptibility as a function of the temperature suggest a phase transition around KT/J ≈ 4.5 and was evidenced the problem of finite size of the lattice to work with large lattice. (paper)

  12. 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}.

  13. Nature versus nurture: Predictability in low-temperature Ising dynamics

    Science.gov (United States)

    Ye, J.; Machta, J.; Newman, C. M.; Stein, D. L.

    2013-10-01

    Consider a dynamical many-body system with a random initial state subsequently evolving through stochastic dynamics. What is the relative importance of the initial state (“nature”) versus the realization of the stochastic dynamics (“nurture”) in predicting the final state? We examined this question for the two-dimensional Ising ferromagnet following an initial deep quench from T=∞ to T=0. We performed Monte Carlo studies on the overlap between “identical twins” raised in independent dynamical environments, up to size L=500. Our results suggest an overlap decaying with time as t-θh with θh=0.22±0.02; the same exponent holds for a quench to low but nonzero temperature. This “heritability exponent” may equal the persistence exponent for the two-dimensional Ising ferromagnet, but the two differ more generally.

  14. Semiconductor of spinons: from Ising band insulator to orthogonal band insulator.

    Science.gov (United States)

    Farajollahpour, T; Jafari, S A

    2018-01-10

    We use the ionic Hubbard model to study the effects of strong correlations on a two-dimensional semiconductor. The spectral gap in the limit where on-site interactions are zero is set by the staggered ionic potential, while in the strong interaction limit it is set by the Hubbard U. Combining mean field solutions of the slave spin and slave rotor methods, we propose two interesting gapped phases in between: (i) the insulating phase before the Mott phase can be viewed as gapping a non-Fermi liquid state of spinons by the staggered ionic potential. The quasi-particles of underlying spinons are orthogonal to physical electrons, giving rise to the 'ARPES-dark' state where the ARPES gap will be larger than the optical and thermal gap. (ii) The Ising insulator corresponding to ordered phase of the Ising variable is characterized by single-particle excitations whose dispersion is controlled by Ising-like temperature and field dependences. The temperature can be conveniently employed to drive a phase transition between these two insulating phases where Ising exponents become measurable by ARPES and cyclotron resonance. The rare earth monochalcogenide semiconductors where the magneto-resistance is anomalously large can be a candidate system for the Ising band insulator. We argue that the Ising and orthogonal insulating phases require strong enough ionic potential to survive the downward renormalization of the ionic potential caused by Hubbard U.

  15. Restoration of dimensional reduction in the random-field Ising model at five dimensions

    Science.gov (United States)

    Fytas, Nikolaos G.; Martín-Mayor, Víctor; Picco, Marco; Sourlas, Nicolas

    2017-04-01

    The random-field Ising model is one of the few disordered systems where the perturbative renormalization group can be carried out to all orders of perturbation theory. This analysis predicts dimensional reduction, i.e., that the critical properties of the random-field Ising model in D dimensions are identical to those of the pure Ising ferromagnet in D -2 dimensions. It is well known that dimensional reduction is not true in three dimensions, thus invalidating the perturbative renormalization group prediction. Here, we report high-precision numerical simulations of the 5D random-field Ising model at zero temperature. We illustrate universality by comparing different probability distributions for the random fields. We compute all the relevant critical exponents (including the critical slowing down exponent for the ground-state finding algorithm), as well as several other renormalization-group invariants. The estimated values of the critical exponents of the 5D random-field Ising model are statistically compatible to those of the pure 3D Ising ferromagnet. These results support the restoration of dimensional reduction at D =5 . We thus conclude that the failure of the perturbative renormalization group is a low-dimensional phenomenon. We close our contribution by comparing universal quantities for the random-field problem at dimensions 3 ≤D equality at all studied dimensions.

  16. Semiconductor of spinons: from Ising band insulator to orthogonal band insulator

    Science.gov (United States)

    Farajollahpour, T.; Jafari, S. A.

    2018-01-01

    We use the ionic Hubbard model to study the effects of strong correlations on a two-dimensional semiconductor. The spectral gap in the limit where on-site interactions are zero is set by the staggered ionic potential, while in the strong interaction limit it is set by the Hubbard U. Combining mean field solutions of the slave spin and slave rotor methods, we propose two interesting gapped phases in between: (i) the insulating phase before the Mott phase can be viewed as gapping a non-Fermi liquid state of spinons by the staggered ionic potential. The quasi-particles of underlying spinons are orthogonal to physical electrons, giving rise to the ‘ARPES-dark’ state where the ARPES gap will be larger than the optical and thermal gap. (ii) The Ising insulator corresponding to ordered phase of the Ising variable is characterized by single-particle excitations whose dispersion is controlled by Ising-like temperature and field dependences. The temperature can be conveniently employed to drive a phase transition between these two insulating phases where Ising exponents become measurable by ARPES and cyclotron resonance. The rare earth monochalcogenide semiconductors where the magneto-resistance is anomalously large can be a candidate system for the Ising band insulator. We argue that the Ising and orthogonal insulating phases require strong enough ionic potential to survive the downward renormalization of the ionic potential caused by Hubbard U.

  17. A Windows-95 based DAS software for the determination of chloride and fluoride in MOX fuel samples by pyrohydrolysis-ISE method

    Energy Technology Data Exchange (ETDEWEB)

    Govindan, R; Kulkarni, Atul; Sivashankaran, G; Raul, Seema; Behere, P G; Mallik, G K; Bhargava, V K; Kamath, H S [Advanced Fuel Fabrication Facility, Bhabha Atomic Research Centre, Tarapur (India)

    1999-01-01

    A Windows-95 based Data Acquisition System (DAS) software has been developed to determine chloride and fluoride in MOX (Mixed Oxide) fuel pellets by pyrohydrolysis followed by Ion Selective Electrodes (ISE). The DAS software controls the furnace remotely and acquires data related to ion-85 ion analyser through RS-232C serial port. This results in ease of operation of furnace during pyrohydrolysis and storage of measured data from ion-85 ion analyser for future use. (author) 4 refs., 1 fig., 3 tabs.

  18. Localized endomorphisms of the chiral Ising model

    International Nuclear Information System (INIS)

    Boeckenhauer, J.

    1994-07-01

    In the frame of the treatment of the chiral Ising model by Mack and Schomerus, examples of localized endomorphisms ρ 1 loc and ρ 1/2 loc are presented. It is shown that they lead to the same superselection sectors as the global ones in the sense that π 0 oρ 1 log ≅π 1 and π 0 pρ 1/2 loc ≅π 1/2 holds. For proving the latter unitary equivalence, Arakis formalism of the selfdual CAR algebra is used. Further it is shown that the localized endomorphisms obey the Ising fusion rules. (orig.)

  19. Transverse Ising spin-glass model

    International Nuclear Information System (INIS)

    Santos, Raimundo R. dos; Santos, R.M.Z. dos.

    1984-01-01

    The zero temperature behavior of the Transverse Ising spin-glass (+-J 0 ) model is discussed. The d-dimensional quantum model is shown to be equivalent to a classical (d + 1)- dimensional Ising spin-glass with correlated disorder. An exact Renormalization Group treatment of the one-dimensional quantum model indicates the existence of a spin-glass phase. The Migdal-Kadanoff approximation is used to obtain the phase diagram of the quantum spin-glass in two-dimensions. (Author) [pt

  20. 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)

  1. Dynamical TAP equations for non-equilibrium Ising spin glasses

    DEFF Research Database (Denmark)

    Roudi, Yasser; Hertz, John

    2011-01-01

    We derive and study dynamical TAP equations for Ising spin glasses obeying both synchronous and asynchronous dynamics using a generating functional approach. The system can have an asymmetric coupling matrix, and the external fields can be time-dependent. In the synchronously updated model, the TAP...... equations take the form of self consistent equations for magnetizations at time t+1, given the magnetizations at time t. In the asynchronously updated model, the TAP equations determine the time derivatives of the magnetizations at each time, again via self consistent equations, given the current values...... of the magnetizations. Numerical simulations suggest that the TAP equations become exact for large systems....

  2. The Information Science Experiment System - The computer for science experiments in space

    Science.gov (United States)

    Foudriat, Edwin C.; Husson, Charles

    1989-01-01

    The concept of the Information Science Experiment System (ISES), potential experiments, and system requirements are reviewed. The ISES is conceived as a computer resource in space whose aim is to assist computer, earth, and space science experiments, to develop and demonstrate new information processing concepts, and to provide an experiment base for developing new information technology for use in space systems. The discussion covers system hardware and architecture, operating system software, the user interface, and the ground communication link.

  3. Weak universality in inhomogeneous Ising quantum chains

    International Nuclear Information System (INIS)

    Karevski, Dragi

    2006-01-01

    The Ising quantum chain with arbitrary coupling distribution {λ i } leading to an anisotropic scaling is considered. The smallest gap of the chain is connected to the surface magnetization by the relation Λ 1 = m s ({λ i })m s ({λ -1 i }). For some aperiodic distribution {λ i }, a weak universality of the critical behaviour is found. (letter to the editor)

  4. ISEE : An Intuitive Sound Editing Environment

    NARCIS (Netherlands)

    Vertegaal, R.P.H.; Bonis, E.

    1994-01-01

    This article presents ISEE, an intuitive sound editing environment, as a general sound synthesis model based on expert auditory perception and cognition of musical instruments. It discusses the backgrounds of current synthesizer user interface design and related timbre space research. Of the three

  5. Monte Carlo technique for very large ising models

    Science.gov (United States)

    Kalle, C.; Winkelmann, V.

    1982-08-01

    Rebbi's multispin coding technique is improved and applied to the kinetic Ising model with size 600*600*600. We give the central part of our computer program (for a CDC Cyber 76), which will be helpful also in a simulation of smaller systems, and describe the other tricks necessary to go to large lattices. The magnetization M at T=1.4* T c is found to decay asymptotically as exp(-t/2.90) if t is measured in Monte Carlo steps per spin, and M( t = 0) = 1 initially.

  6. Nonequilibrium dynamic critical scaling of the quantum Ising chain.

    Science.gov (United States)

    Kolodrubetz, Michael; Clark, Bryan K; Huse, David A

    2012-07-06

    We solve for the time-dependent finite-size scaling functions of the one-dimensional transverse-field Ising chain during a linear-in-time ramp of the field through the quantum critical point. We then simulate Mott-insulating bosons in a tilted potential, an experimentally studied system in the same equilibrium universality class, and demonstrate that universality holds for the dynamics as well. We find qualitatively athermal features of the scaling functions, such as negative spin correlations, and we show that they should be robustly observable within present cold atom experiments.

  7. Ising and Potts models: binding disorder-and dimension effects

    International Nuclear Information System (INIS)

    Curado, E.M.F.

    1983-01-01

    Within the real space renormalization group framework, some thermal equilibrium properties of pure and disordered insulating systems are calculated. In the pure hypercubic lattice system, the Ising model surface tension and the correlation length of the q-state Potts model, which generalizes the former are analyzed. Several asymptotic behaviors are obtained (for the first time as far as we know) for both functions and the influence of dimension over them can be observed. Accurate numerical proposals for the surface tension are made in several dimensions, and the effect of the number of states (q) on the correlation lenght is shown. In disordered systems, attention is focused essentiall on those which can be theoretically represented by pure sistem Hamiltonians where probability distributions are assumed for the coupling constants (disorder in the bonds). It is obtained with high precision several approximate critical surfaces for the quenched square-lattice Ising model, whose probability distribution can assume two positive values (hence there is no frustration). These aproximate surfaces contain all the exact known points. In the cases where the coupling constant probability distribution can also assume negative values (allowing disordered and frustrated systems), a theoretical treatment which distinguishes the frustration effect from the dilution one is proposed. This distinction can be seen by the different ways in which the bonds of any series-parallel topological array combine. (Author) [pt

  8. Generation of Control by SU(2) Reduction for the Anisotropic Ising Model

    International Nuclear Information System (INIS)

    Delgado, F

    2016-01-01

    Control of entanglement is fundamental in Quantum Information and Quantum Computation towards scalable spin-based quantum devices. For magnetic systems, Ising interaction with driven magnetic fields modifies entanglement properties of matter based quantum systems. This work presents a procedure for dynamics reduction on SU(2) subsystems using a non-local description. Some applications for Quantum Information are discussed. (paper)

  9. WEAK EFFICIENCY ON THE STOCK EXCHANGE MARKET: AN EMPIRICAL STUDY ON ISE

    Directory of Open Access Journals (Sweden)

    SİBEL DUMAN ATAN

    2013-06-01

    Full Text Available Markets which returns of share certificate are reflected completely whole information, describe as effective. In a weak-form efficiency market, all past price activity were reflected with current price and it isn’t obtaining an above the normal return to use with past price activity in markets. In this paper, we aim to provide the efficiency level of ISE market using fifteen minutes and session frequency data for the 03 January 2003 – 30 December 2005 period. In order to test the efficiency of ISE we use firstly ADF and KPSS unit root tests and secondly ELW fractionally integrated estimator developed by Shimotsu and Philips (2005. According to application we found that ISE is weakly efficient market.

  10. Monte Carlo Simulations of Compressible Ising Models: Do We Understand Them?

    Science.gov (United States)

    Landau, D. P.; Dünweg, B.; Laradji, M.; Tavazza, F.; Adler, J.; Cannavaccioulo, L.; Zhu, X.

    Extensive Monte Carlo simulations have begun to shed light on our understanding of phase transitions and universality classes for compressible Ising models. A comprehensive analysis of a Landau-Ginsburg-Wilson hamiltonian for systems with elastic degrees of freedom resulted in the prediction that there should be four distinct cases that would have different behavior, depending upon symmetries and thermodynamic constraints. We shall provide an account of the results of careful Monte Carlo simulations for a simple compressible Ising model that can be suitably modified so as to replicate all four cases.

  11. Effective-field treatment of an anisotropic Ising ferromagnet: thermodynamical properties

    International Nuclear Information System (INIS)

    Sarmento, E.F.; Honmura, R.; Tsallis, C.

    1982-01-01

    The anisotropic square lattice spin -1/2 Ising ferromagnet is discussed. Through this system it is illustrated how all relevant thermodynamical quantities (phase diagram, magnetization, short range order parameter, specific heat and susceptibility) can be approximatively calculated within an effective-field unified procedure (which substantially improves the Mean Field Approximation). Two slightly different approximations for the susceptibility (whose exact computation is still lacking) are presented. The (square lattice) - (linear chain) crossover is exhibited. The present (mathematically simple) procedures could be useful in the study of complex Ising problems. (Author) [pt

  12. Phase diagrams of diluted transverse Ising nanowire

    Energy Technology Data Exchange (ETDEWEB)

    Bouhou, S.; Essaoudi, I. [Laboratoire de Physique des Matériaux et Modélisation, des Systèmes, (LP2MS), Unité Associée au CNRST-URAC 08, University of Moulay Ismail, Physics Department, Faculty of Sciences, B.P. 11201 Meknes (Morocco); Ainane, A., E-mail: ainane@pks.mpg.de [Laboratoire de Physique des Matériaux et Modélisation, des Systèmes, (LP2MS), Unité Associée au CNRST-URAC 08, University of Moulay Ismail, Physics Department, Faculty of Sciences, B.P. 11201 Meknes (Morocco); Max-Planck-Institut für Physik Complexer Systeme, Nöthnitzer Str. 38 D-01187 Dresden (Germany); Saber, M. [Laboratoire de Physique des Matériaux et Modélisation, des Systèmes, (LP2MS), Unité Associée au CNRST-URAC 08, University of Moulay Ismail, Physics Department, Faculty of Sciences, B.P. 11201 Meknes (Morocco); Max-Planck-Institut für Physik Complexer Systeme, Nöthnitzer Str. 38 D-01187 Dresden (Germany); Ahuja, R. [Condensed Matter Theory Group, Department of Physics and Astronomy, Uppsala University, 75120 Uppsala (Sweden); Dujardin, F. [Laboratoire de Chimie et Physique des Milieux Complexes (LCPMC), Institut de Chimie, Physique et Matériaux (ICPM), 1 Bd. Arago, 57070 Metz (France)

    2013-06-15

    In this paper, the phase diagrams of diluted Ising nanowire consisting of core and surface shell coupling by J{sub cs} exchange interaction are studied using the effective field theory with a probability distribution technique, in the presence of transverse fields in the core and in the surface shell. We find a number of characteristic phenomena. In particular, the effect of concentration c of magnetic atoms, the exchange interaction core/shell, the exchange in surface and the transverse fields in core and in surface shell of phase diagrams are investigated. - Highlights: ► We use the EFT to investigate the phase diagrams of Ising transverse nanowire. ► Ferrimagnetic and ferromagnetic cases are investigated. ► The effects of the dilution and the transverse fields in core and shell are studied. ► Behavior of the transition temperature with the exchange interaction is given.

  13. Phase diagrams of diluted transverse Ising nanowire

    International Nuclear Information System (INIS)

    Bouhou, S.; Essaoudi, I.; Ainane, A.; Saber, M.; Ahuja, R.; Dujardin, F.

    2013-01-01

    In this paper, the phase diagrams of diluted Ising nanowire consisting of core and surface shell coupling by J cs exchange interaction are studied using the effective field theory with a probability distribution technique, in the presence of transverse fields in the core and in the surface shell. We find a number of characteristic phenomena. In particular, the effect of concentration c of magnetic atoms, the exchange interaction core/shell, the exchange in surface and the transverse fields in core and in surface shell of phase diagrams are investigated. - Highlights: ► We use the EFT to investigate the phase diagrams of Ising transverse nanowire. ► Ferrimagnetic and ferromagnetic cases are investigated. ► The effects of the dilution and the transverse fields in core and shell are studied. ► Behavior of the transition temperature with the exchange interaction is given

  14. In-Situ Ion Analysis of Fresh Waters via an ISE Multiprobe and Artificial Neural Networks

    Science.gov (United States)

    Mueller, A. V.; Hemond, H.

    2010-12-01

    The ecological and geochemical sciences stand to substantially gain from capability for comprehensive, real-time, in-situ characterization of the chemical constituents of natural waters, e.g. by facilitating rapid high-resolution adaptive sampling campaigns and avoiding the potential errors and high costs related to traditional grab sample collection, transportation and in-lab analysis. In-situ chemical instrumentation also promotes the goals of large-scale monitoring networks, such as CUASHI and WATERS, by reducing the financial and human resources overhead required for traditional sampling at this scale. Problems of environmental remediation and monitoring of industrial waste waters would additionally benefit from such instrumental capacity. We have pursued in-situ measurement of all major ions contributing to the charge makeup (>99%) of oxic natural fresh waters via an instrument combining an array of ion-selective electrode (ISE) hardware with an appropriate multivariate signal processing architecture. Commercially available electrochemical sensors promote low cost and a fast development schedule, as well as easy maintenance and reproduction. Data processing techniques are adapted from artificial intelligence and chemometrics to extract accurate information from the corresponding in-situ data matrix. This architecture takes into account temperature, conductivity, and non-linearity effects, as well as taking advantage of sensor cross-selectivities traditionally considered as interferences. Chemical and mathematical constraints, e.g. charge balance and total ionic strength, provide further system-level information. Maximizing data recovery from the sensor array allows use of the instrument without the standard additions or ionic strength adjustment traditionally-required with use of ISEs. Initial work demonstrates the effectiveness of this methodology at predicting inorganic cations (sodium, potassium, calcium, and ammonium ) and hydrogen ion in a simplified

  15. ISEE-magnetopause observations - workshop results

    International Nuclear Information System (INIS)

    Paschmann, G.

    1982-01-01

    A brief history of ISEE magnetopause workshops held during 1977-1981 is presented, and an assessment of the activity of these workshops is made. Workshop results are surveyed, with attention given to magnetopause thickness and speed, large-scale reconnection, small-scale reconnection, magnetic field topology, plasma waves, boundary layer structure, surface waves, plasma origin, and the relationship between magnetopause and particle boundaries. Finally, a few topics that require particular attention in the future are mentioned

  16. Factors controlling degree of correlation between ISEE 1 and ISEE 3 interplanetary magnetic field measurements

    International Nuclear Information System (INIS)

    Crooker, N.U.; Siscoe, G.L.; Russell, C.T.; Smith, E.J.

    1982-01-01

    The degree of correlation between ISEE 1 and ISEE 3 IMF measurements is highly variable. Approximately 200 two-hour periods when the correlation was good and 200 more when the correlation was poor are used to determine the relative control of several factors over the degree of correlation. Both IMF variance and spacecraft separation distance in the plane perpendicular to the earth-sun line exert substantial control. Good correlations are associated with high variance and distances less than 90 R/sub E/. During periods of highest variance, good correlations occur at distances beyond 90 R/sub E/ up to 120 R/sub E/, the maximum range of ISEE 1-ISEE 3 separation. Thus it appears that the scale size of magnetic features is larger when the variance is high. Abrupt changes in the correlation coefficient from poor to good or good to poor in adjacent two-hour intervals appear to be governed by the sense of change of IMF variance: changes in correlation from poor to good correspond to increasing variance and vice versa. The IMF orientation also exerts control over the degree of correlation. During periods of low variance, good correlations are most likely to occur when the distance between ISEE 1 and ISEE 3 perpendicular to the IMF is less than 20 R/sub E/. This scale size expands to approx.50 R/sub E/ during periods of high variance. Solar wind speed shows little control over the degree of correlation in the speed range 300--500 km/s

  17. Ising percolation in a three-state majority vote model

    Energy Technology Data Exchange (ETDEWEB)

    Balankin, Alexander S., E-mail: abalankin@ipn.mx [Grupo Mecánica Fractal, ESIME, Instituto Politécnico Nacional, México D.F., 07738 (Mexico); Martínez-Cruz, M.A.; Gayosso Martínez, Felipe [Grupo Mecánica Fractal, ESIME, Instituto Politécnico Nacional, México D.F., 07738 (Mexico); Mena, Baltasar [Laboratorio de Ingeniería y Procesos Costeros, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Sisal, Yucatán, 97355 (Mexico); Tobon, Atalo; Patiño-Ortiz, Julián; Patiño-Ortiz, Miguel; Samayoa, Didier [Grupo Mecánica Fractal, ESIME, Instituto Politécnico Nacional, México D.F., 07738 (Mexico)

    2017-02-05

    Highlights: • Three-state non-consensus majority voter model is introduced. • Phase transition in the absorbing state non-consensus is revealed. • The percolation transition belongs to the universality class of Ising percolation. • The effect of an updating rule for a tie between voter neighbors is highlighted. - Abstract: In this Letter, we introduce a three-state majority vote model in which each voter adopts a state of a majority of its active neighbors, if exist, but the voter becomes uncommitted if its active neighbors are in a tie, or all neighbors are the uncommitted. Numerical simulations were performed on square lattices of different linear size with periodic boundary conditions. Starting from a random distribution of active voters, the model leads to a stable non-consensus state in which three opinions coexist. We found that the “magnetization” of the non-consensus state and the concentration of uncommitted voters in it are governed by an initial composition of system and are independent of the lattice size. Furthermore, we found that a configuration of the stable non-consensus state undergoes a second order percolation transition at a critical concentration of voters holding the same opinion. Numerical simulations suggest that this transition belongs to the same universality class as the Ising percolation. These findings highlight the effect of an updating rule for a tie between voter neighbors on the critical behavior of models obeying the majority vote rule whenever a strict majority exists.

  18. Ising percolation in a three-state majority vote model

    International Nuclear Information System (INIS)

    Balankin, Alexander S.; Martínez-Cruz, M.A.; Gayosso Martínez, Felipe; Mena, Baltasar; Tobon, Atalo; Patiño-Ortiz, Julián; Patiño-Ortiz, Miguel; Samayoa, Didier

    2017-01-01

    Highlights: • Three-state non-consensus majority voter model is introduced. • Phase transition in the absorbing state non-consensus is revealed. • The percolation transition belongs to the universality class of Ising percolation. • The effect of an updating rule for a tie between voter neighbors is highlighted. - Abstract: In this Letter, we introduce a three-state majority vote model in which each voter adopts a state of a majority of its active neighbors, if exist, but the voter becomes uncommitted if its active neighbors are in a tie, or all neighbors are the uncommitted. Numerical simulations were performed on square lattices of different linear size with periodic boundary conditions. Starting from a random distribution of active voters, the model leads to a stable non-consensus state in which three opinions coexist. We found that the “magnetization” of the non-consensus state and the concentration of uncommitted voters in it are governed by an initial composition of system and are independent of the lattice size. Furthermore, we found that a configuration of the stable non-consensus state undergoes a second order percolation transition at a critical concentration of voters holding the same opinion. Numerical simulations suggest that this transition belongs to the same universality class as the Ising percolation. These findings highlight the effect of an updating rule for a tie between voter neighbors on the critical behavior of models obeying the majority vote rule whenever a strict majority exists.

  19. Noise as a Probe of Ising Spin Glass Transitions

    Science.gov (United States)

    Chen, Zhi; Yu, Clare

    2009-03-01

    Noise is ubiquitous and and is often viewed as a nuisance. However, we propose that noise can be used as a probe of the fluctuations of microscopic entities, especially in the vicinity of a phase transition. In recent work we have used simulations to show that the noise increases in the vicinity of phase transitions of ordered systems. We have recently turned our attention to noise near the phase transitions of disordered systems. In particular, we are studying the noise near Ising spin glass transitions using Monte Carlo simulations. We monitor the system as a function of temperature. At each temperature, we obtain the time series of quantities characterizing the properties of the system, i.e., the energy and magnetization. We look at different quantities, such as the noise power spectrum and the second spectrum of the noise, to analyze the fluctuations.

  20. THE EFFECT OF INVESTOR SENTIMENT ON ISE SECTOR INDICES

    Directory of Open Access Journals (Sweden)

    SERPİL CANBAŞ

    2013-06-01

    Full Text Available Determining the factors that affect stock returns is one of the most investigated topics of the finance literature. A number of models have been developed to explain stock returns. Some of these models maintain that stock returns are generated rationally. These models are, Capital Asset Pricing Model, Index Models, Arbitrage Pricing Model and Macroeconomic Factor Models. Nevertheless, these models could not have explained stock returns, although they have used different parameters and methods. Some studies have maintained that investor psychology would have a role in the stock return generation process. There are three theories that investigate the effect of investor psychology on financial markets: Mental accounting theory, herd behavior theory and investor sentiment theory. The aim of this study is to investigate the effect of investor sentiment on stock returns. In this context, three investor sentiment proxies have been determined in the light of previous studies. These proxies are closed-end fund discount, average fund flow of mutual funds and the ratio of net stock purchases of foreign investors to ISE market capitalization. ISE sector indices are used to proxy stock returns. On the other hand, there is a possibility that investor sentiment would merely reflect economic innovations. Some economic factors are used as control variables in order to examine this possibility. Regression analyses are employed for investigating the effect of investor sentiment on stock returns. Findings suggest that investor sentiment affect stock returns systematically. This finding keeps its robustness when economic variables are added to the model.

  1. Transient time of an Ising machine based on injection-locked laser network

    International Nuclear Information System (INIS)

    Takata, Kenta; Utsunomiya, Shoko; Yamamoto, Yoshihisa

    2012-01-01

    We numerically study the dynamics and frequency response of the recently proposed Ising machine based on the polarization degrees of freedom of an injection-locked laser network (Utsunomiya et al 2011 Opt. Express 19 18091). We simulate various anti-ferromagnetic Ising problems, including the ones with symmetric Ising and Zeeman coefficients, which enable us to study the problem size up to M = 1000. Transient time, to reach a steady-state polarization configuration after a given Ising problem is mapped onto the system, is inversely proportional to the locking bandwidth and does not scale exponentially with the problem size. In the Fourier analysis with first-order linearization approximation, we find that the cut-off frequency of a system's response is almost identical to the locking bandwidth, which supports the time-domain analysis. It is also shown that the Zeeman term, which is created by the horizontally polarized injection signal from the master laser, serves as an initial driving force on the system and contributes to the transient time in addition to the inverse locking bandwidth. (paper)

  2. An effective correlated mean-field theory applied in the spin-1/2 Ising ferromagnetic model

    Energy Technology Data Exchange (ETDEWEB)

    Roberto Viana, J.; Salmon, Octávio R. [Universidade Federal do Amazonas – UFAM, Manaus 69077-000, AM (Brazil); Ricardo de Sousa, J. [Universidade Federal do Amazonas – UFAM, Manaus 69077-000, AM (Brazil); National Institute of Science and Technology for Complex Systems, Universidade Federal do Amazonas, 3000, Japiim, 69077-000 Manaus, AM (Brazil); Neto, Minos A.; Padilha, Igor T. [Universidade Federal do Amazonas – UFAM, Manaus 69077-000, AM (Brazil)

    2014-11-15

    We developed a new treatment for mean-field theory applied in spins systems, denominated effective correlated mean-field (ECMF). We apply this theory to study the spin-1/2 Ising ferromagnetic model with nearest-neighbor interactions on a square lattice. We use clusters of finite sizes and study the criticality of the ferromagnetic system, where we obtain a convergence of critical temperature for the value k{sub B}T{sub c}/J≃2.27905±0.00141. Also the behavior of magnetic and thermodynamic properties, using the condition of minimum energy of the physical system is obtained. - Highlights: • We developed spin models to study real magnetic systems. • We study the thermodynamic and magnetic properties of the ferromagnetism. • We enhanced a mean-field theory applied in spins models.

  3. Mobile systems development

    DEFF Research Database (Denmark)

    Pedersen, Ole; Kristiansen, Martin Lund; Kammersgaard, Marc N.

    2007-01-01

    in XP. In general, we find XP well-suited for mobile systems development projects. However, based on our experiences and an analytical comparison we propose the following modifications to XP: Make an essential design to avoid the worst time waste during refactoring. For faster development, reuse code......Development of mobile software is Surrounded by much uncertainty. Immature software platforms on mobile clients, a highly competitive market calling for innovation, efficiency and effectiveness in the development life cycle, and lacking end-user adoption are just some of the realities facing...... development teams in the mobile software industry. By taking a process view on development of mobile systems we seek to explore the strengths and limitations of eXtreme Programming (XP) in the context of mobile software development. Following an experimental approach a mobile systems development project...

  4. Doing Systems Development

    DEFF Research Database (Denmark)

    Koch, Christian; Mathiasen, John Bang

    2014-01-01

    Systems development of wind turbine control is competitive with respect to innovation, time and cost. So how can learning possibly occur under such circumstances? Dewey’s pragmatist approach to learning is adopted, emphasising reciprocity between the systems developer’s individual experience...... and the sociotechnical practice. The framework involves the concepts of sociotechnical practice, anchoring of indeterminate situation, and strip of doings towards determinate situation. An ethnographic study was made of four cases of systems development and learning do occur in the cases, enabled by converging anchoring...... of the indeterminate situation and the systems developers different experience. However, an extreme case reveals initiated learning processes and that the interchanges between materiality of the artefacts and systems developers block the learning processes due to a customer with imprecise demands and unclear system...

  5. Entanglement negativity in the critical Ising chain

    International Nuclear Information System (INIS)

    Calabrese, Pasquale; Tagliacozzo, Luca; Tonni, Erik

    2013-01-01

    We study the scaling of the traces of the integer powers of the partially transposed reduced density matrix Tr(ρ A T 2 ) n and of the entanglement negativity for two spin blocks as a function of their length and separation in the critical Ising chain. For two adjacent blocks, we show that tensor network calculations agree with universal conformal field theory (CFT) predictions. In the case of two disjoint blocks the CFT predictions are recovered only after taking into account the finite size corrections induced by the finite length of the blocks. (paper)

  6. Inverse Ising Inference Using All the Data

    Science.gov (United States)

    Aurell, Erik; Ekeberg, Magnus

    2012-03-01

    We show that a method based on logistic regression, using all the data, solves the inverse Ising problem far better than mean-field calculations relying only on sample pairwise correlation functions, while still computationally feasible for hundreds of nodes. The largest improvement in reconstruction occurs for strong interactions. Using two examples, a diluted Sherrington-Kirkpatrick model and a two-dimensional lattice, we also show that interaction topologies can be recovered from few samples with good accuracy and that the use of l1 regularization is beneficial in this process, pushing inference abilities further into low-temperature regimes.

  7. Quenched random-bond ising ferromagnet

    International Nuclear Information System (INIS)

    Sarmento, E.F.; Honmura, R.; Tsallis, C.; Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro)

    1984-01-01

    A effective-field framework which, without mathematical complexities, enables the calculation of the phase diagram (and magnetization) associated with a quenched bond-mixed spin - 1/2 Ising model in an anisotropic simple cubic lattice have been recently introduced. The case corresponding to anisotropic coupling constants but isotropic concentrations was discussed in detail. Herein the case corresponding to isotropic coupling constants but anisotropic concentrations is discussed. A certain amount of interesting phase diagrams are exhibited; whenever comparison with available data is possible, the present results provide a satisfactory qualitative (and to a certain extent quantitative) agreement. (Author) [pt

  8. Tricritical Ising model with a boundary

    International Nuclear Information System (INIS)

    De Martino, A.; Moriconi, M.

    1998-03-01

    We study the integrable and supersymmetric massive φ (1,3) deformation of the tricritical Ising model in the presence of a boundary. We use constraints from supersymmetry in order to compute the exact boundary S-matrices, which turn out to depend explicitly on the topological charge of the supersymmetry algebra. We also solve the general boundary Yang-Baxter equation and show that in appropriate limits the general reflection matrices go over the supersymmetry preserving solutions. Finally, we briefly discuss the possible connection between our reflection matrices and boundary perturbations within the framework of perturbed boundary conformal field theory. (author)

  9. Development of taste sensor system for differentiation of Indonesian herbal medicines

    Energy Technology Data Exchange (ETDEWEB)

    Kaltsum, U., E-mail: um-mik@yahoo.co.id [Physics Education Department, IKIP PGRI Semarang (Indonesia); Triyana, K., E-mail: triyana@ugm.ac.id; Siswanta, D., E-mail: triyana@ugm.ac.id [Physics Department, Gadjah Mada University (Indonesia)

    2014-09-25

    In Indonesia, herbal medicines are usually produced by small and medium enterprises which are relatively low in quality control. The purpose of this paper is to report that we have developed a taste sensor system with global selectivity, i.e., electronic tongue (e-tongue) for differentiation of Indonesian herbal medicines. The e-tongue was composed of five kinds of ion selective electrodes as working electrodes, data acquisition system, and pattern recognition system. Each ion selective electrode (ISE) was built by attaching lipid/polymer membrane. For this purpose, the five kinds of membranes were built by mixing lipid, plasticizer (nitrophenyl octyl ether/NPOE), polyvinyl chloride (PVC), and tetrahydrofuran (THF). In this study, we employed five kinds of lipid, namely oleic acid (OA), dioctyl phosphate (DOP), decyl alcohol (DA), dodecylamine (DDC), and trioctyl methyl ammonium chloride (TOMA). In this case, the membranes transform information of taste substances into electric signal. The five kinds of Indonesian herbal medicine were purchased from local supermarket in Yogyakarta, i.e., kunyit asam (made from turmeric and tamarind), beras kencur (made from rice and kencur), jahe wangi (made from ginger and fragrance), sirih wangi (made from betel leaf), and temulawak (made from Javanese ginger). Prior to detecting the taste from the Indonesian herbal medicine samples, each ion selective electrode was tested with five basic taste samples, i.e., for saltiness, sweetness, umami, bitterness, and sourness. All ISEs showed global selectivity to all samples. Furthermore, the array of ISEs showed specific response pattern to each Indonesian herbal medicine. For pattern recognition system, we employed principle component analysis (PCA). As a result, the e-tongue was able to differentiate five kinds of Indonesian herbal medicines, proven by the total variance of first and second principle components is about 93%. For the future, the e-tongue may be developed for quality

  10. Development of taste sensor system for differentiation of Indonesian herbal medicines

    International Nuclear Information System (INIS)

    Kaltsum, U.; Triyana, K.; Siswanta, D.

    2014-01-01

    In Indonesia, herbal medicines are usually produced by small and medium enterprises which are relatively low in quality control. The purpose of this paper is to report that we have developed a taste sensor system with global selectivity, i.e., electronic tongue (e-tongue) for differentiation of Indonesian herbal medicines. The e-tongue was composed of five kinds of ion selective electrodes as working electrodes, data acquisition system, and pattern recognition system. Each ion selective electrode (ISE) was built by attaching lipid/polymer membrane. For this purpose, the five kinds of membranes were built by mixing lipid, plasticizer (nitrophenyl octyl ether/NPOE), polyvinyl chloride (PVC), and tetrahydrofuran (THF). In this study, we employed five kinds of lipid, namely oleic acid (OA), dioctyl phosphate (DOP), decyl alcohol (DA), dodecylamine (DDC), and trioctyl methyl ammonium chloride (TOMA). In this case, the membranes transform information of taste substances into electric signal. The five kinds of Indonesian herbal medicine were purchased from local supermarket in Yogyakarta, i.e., kunyit asam (made from turmeric and tamarind), beras kencur (made from rice and kencur), jahe wangi (made from ginger and fragrance), sirih wangi (made from betel leaf), and temulawak (made from Javanese ginger). Prior to detecting the taste from the Indonesian herbal medicine samples, each ion selective electrode was tested with five basic taste samples, i.e., for saltiness, sweetness, umami, bitterness, and sourness. All ISEs showed global selectivity to all samples. Furthermore, the array of ISEs showed specific response pattern to each Indonesian herbal medicine. For pattern recognition system, we employed principle component analysis (PCA). As a result, the e-tongue was able to differentiate five kinds of Indonesian herbal medicines, proven by the total variance of first and second principle components is about 93%. For the future, the e-tongue may be developed for quality

  11. Development of taste sensor system for differentiation of Indonesian herbal medicines

    Science.gov (United States)

    Kaltsum, U.; Triyana, K.; Siswanta, D.

    2014-09-01

    In Indonesia, herbal medicines are usually produced by small and medium enterprises which are relatively low in quality control. The purpose of this paper is to report that we have developed a taste sensor system with global selectivity, i.e., electronic tongue (e-tongue) for differentiation of Indonesian herbal medicines. The e-tongue was composed of five kinds of ion selective electrodes as working electrodes, data acquisition system, and pattern recognition system. Each ion selective electrode (ISE) was built by attaching lipid/polymer membrane. For this purpose, the five kinds of membranes were built by mixing lipid, plasticizer (nitrophenyl octyl ether/NPOE), polyvinyl chloride (PVC), and tetrahydrofuran (THF). In this study, we employed five kinds of lipid, namely oleic acid (OA), dioctyl phosphate (DOP), decyl alcohol (DA), dodecylamine (DDC), and trioctyl methyl ammonium chloride (TOMA). In this case, the membranes transform information of taste substances into electric signal. The five kinds of Indonesian herbal medicine were purchased from local supermarket in Yogyakarta, i.e., kunyit asam (made from turmeric and tamarind), beras kencur (made from rice and kencur), jahe wangi (made from ginger and fragrance), sirih wangi (made from betel leaf), and temulawak (made from Javanese ginger). Prior to detecting the taste from the Indonesian herbal medicine samples, each ion selective electrode was tested with five basic taste samples, i.e., for saltiness, sweetness, umami, bitterness, and sourness. All ISEs showed global selectivity to all samples. Furthermore, the array of ISEs showed specific response pattern to each Indonesian herbal medicine. For pattern recognition system, we employed principle component analysis (PCA). As a result, the e-tongue was able to differentiate five kinds of Indonesian herbal medicines, proven by the total variance of first and second principle components is about 93%. For the future, the e-tongue may be developed for quality

  12. Industrialized Information Systems Development

    DEFF Research Database (Denmark)

    Havn, Erling; Bansler, Jørgen P.

    1996-01-01

    The production of application software is rapidly being industrialized. Computer manufacturers and software houses produce a rapidly growing number of generic software applications and systems, and more and more user companies choose to build their computer-based information systems...... with such generic products, instead of custom made software. We discuss how the move away from traditional in-house development and the increasing use of generic software is likely to transform IS development in the near future. We conclude that these developments will make new demands on the information systems...

  13. 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

  14. Ising critical behaviour in the one-dimensional frustrated quantum XY model

    International Nuclear Information System (INIS)

    Granato, E.

    1993-06-01

    A generalization of the one-dimensional frustrated quantum XY model is considered in which the inter and intra-chain coupling constants of the two infinite XY (planar rotor) chains have different strengths. The model can describe the superconductor-insulator transition due to charging effects in a ladder of Josephson junctions in a magnetic field with half a flux quantum per plaquette. From a fluctuation-effective action, this transition is expected to be in the universality class of the two-dimensional classical XY-Ising model. The critical behaviour is studied using a Monte Carlo transfer matrix applied to the path-integral representation of the model and a finite-size-scaling analysis of data on small system sizes. It is found that, unlike the previous studied case of equal inter and intra-chain coupling constants, the XY and Ising-like excitations of the quantum model decouple for large interchain coupling, giving rise to pure Ising model critical behaviour for the chirality order parameter in good agreement with the results for the XY-Ising model. (author). 18 refs, 4 figs

  15. Exact solutions to plaquette Ising models with free and periodic boundaries

    International Nuclear Information System (INIS)

    Mueller, Marco; Johnston, Desmond A.; Janke, Wolfhard

    2017-01-01

    An anisotropic limit of the 3d plaquette Ising model, in which the plaquette couplings in one direction were set to zero, was solved for free boundary conditions by Suzuki (1972) , who later dubbed it the fuki-nuke, or “no-ceiling”, model. Defining new spin variables as the product of nearest-neighbour spins transforms the Hamiltonian into that of a stack of (standard) 2d Ising models and reveals the planar nature of the magnetic order, which is also present in the fully isotropic 3d plaquette model. More recently, the solution of the fuki-nuke model was discussed for periodic boundary conditions, which require a different approach to defining the product spin transformation, by Castelnovo et al. (2010) . We clarify the exact relation between partition functions with free and periodic boundary conditions expressed in terms of original and product spin variables for the 2d plaquette and 3d fuki-nuke models, noting that the differences are already present in the 1d Ising model. In addition, we solve the 2d plaquette Ising model with helical boundary conditions. The various exactly solved examples illustrate how correlations can be induced in finite systems as a consequence of the choice of boundary conditions.

  16. Power Systems Development Facility

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2009-01-31

    In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, has routinely demonstrated gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This final report summarizes the results of the technology development work conducted at the PSDF through January 31, 2009. Twenty-one major gasification test campaigns were completed, for a total of more than 11,000 hours of gasification operation. This operational experience has led to significant advancements in gasification technologies.

  17. Coevolution of Glauber-like Ising dynamics and topology

    Science.gov (United States)

    Mandrà, Salvatore; Fortunato, Santo; Castellano, Claudio

    2009-11-01

    We study the coevolution of a generalized Glauber dynamics for Ising spins with tunable threshold and of the graph topology where the dynamics takes place. This simple coevolution dynamics generates a rich phase diagram in the space of the two parameters of the model, the threshold and the rewiring probability. The diagram displays phase transitions of different types: spin ordering, percolation, and connectedness. At variance with traditional coevolution models, in which all spins of each connected component of the graph have equal value in the stationary state, we find that, for suitable choices of the parameters, the system may converge to a state in which spins of opposite sign coexist in the same component organized in compact clusters of like-signed spins. Mean field calculations enable one to estimate some features of the phase diagram.

  18. History of the Lenz–Ising model 1965–1971

    DEFF Research Database (Denmark)

    Niss, Martin

    2011-01-01

    when it was realized that the Lenz–Ising model is actually relevant for the understanding of phase transitions. In this article, which is self-contained, I study how this realization affected attempts to understand critical phenomena, which can be understood as limiting cases of (first-order) phase...... of critical phenomena, for example that diverse physical systems exhibit similar behavior close to a critical point. Later, a more systematic program of understanding critical phenomena emerged that involved an explicit formulation of what it means to understand critical phenomena, namely, the elucidation...... of what features of the Hamiltonian of models lead to what kinds of behavior close to critical points. Attempts to accomplish this program culminated with the so-called hypothesis of universality, put forward independently by Robert B. Griffiths and Leo P. Kadanoff in 1970. They divided critical phenomena...

  19. Antiferromagnetic Ising model with transverse and longitudinal field

    International Nuclear Information System (INIS)

    Kischinhevsky, M.

    1985-01-01

    We study the quantum hamiltonian version of the Ising Model in one spacial dimension under an external longitudinal (uniform) field at zero temperature. A phenomenological renormalization group procedure is used to obtain the phase diagram; the transverse and longitudinal zero field limits are studied and we verify the validity of universality at non zero transverse fields, where two-dimensional critical behaviour is obtained. To perform the numerical calculations we use the Lanczos scheme, which gives highly precise results with rather short processing times. We also analyse the possibility of using these techniques to extend the present work to the quantum hamiltonian version of the q-state Potts Model (q>2) in larger system. (author) [pt

  20. Phase transitions and Heisenberg limited metrology in an Ising chain interacting with a single-mode cavity field

    DEFF Research Database (Denmark)

    Gammelmark, Søren; Mølmer, Klaus

    2011-01-01

    We investigate the thermodynamics of a combined Dicke and Ising model that exhibits a rich phenomenology arising from the second-order and quantum phase transitions from the respective models. The partition function is calculated using mean-field theory, and the free energy is analyzed in detail...... to determine the complete phase diagram of the system. The analysis reveals both first- and second-order Dicke phase transitions into a super-radiant state, and the cavity mean field in this regime acts as an effective magnetic field, which restricts the Ising chain dynamics to parameter ranges away from...... the Ising phase transition. Physical systems with first-order phase transitions are natural candidates for metrology and calibration purposes, and we apply filter theory to show that the sensitivity of the physical system to temperature and external fields reaches the 1/N Heisenberg limit....

  1. RSMASS system model development

    International Nuclear Information System (INIS)

    Marshall, A.C.; Gallup, D.R.

    1998-01-01

    RSMASS system mass models have been used for more than a decade to make rapid estimates of space reactor power system masses. This paper reviews the evolution of the RSMASS models and summarizes present capabilities. RSMASS has evolved from a simple model used to make rough estimates of space reactor and shield masses to a versatile space reactor power system model. RSMASS uses unique reactor and shield models that permit rapid mass optimization calculations for a variety of space reactor power and propulsion systems. The RSMASS-D upgrade of the original model includes algorithms for the balance of the power system, a number of reactor and shield modeling improvements, and an automatic mass optimization scheme. The RSMASS-D suite of codes cover a very broad range of reactor and power conversion system options as well as propulsion and bimodal reactor systems. Reactor choices include in-core and ex-core thermionic reactors, liquid metal cooled reactors, particle bed reactors, and prismatic configuration reactors. Power conversion options include thermoelectric, thermionic, Stirling, Brayton, and Rankine approaches. Program output includes all major component masses and dimensions, efficiencies, and a description of the design parameters for a mass optimized system. In the past, RSMASS has been used as an aid to identify and select promising concepts for space power applications. The RSMASS modeling approach has been demonstrated to be a valuable tool for guiding optimization of the power system design; consequently, the model is useful during system design and development as well as during the selection process. An improved in-core thermionic reactor system model RSMASS-T is now under development. The current development of the RSMASS-T code represents the next evolutionary stage of the RSMASS models. RSMASS-T includes many modeling improvements and is planned to be more user-friendly. RSMASS-T will be released as a fully documented, certified code at the end of

  2. Development of Production Systems

    DEFF Research Database (Denmark)

    Christiansen, Thomas Bøhm

    1997-01-01

    This paper presents the initial considerations related to a Ph.D. study initiated at IPV, DTU in February 1997, concerning the research subject "Development of Production Systems". The content and aim of this paper is to 1) to introduce the study by......This paper presents the initial considerations related to a Ph.D. study initiated at IPV, DTU in February 1997, concerning the research subject "Development of Production Systems". The content and aim of this paper is to 1) to introduce the study by...

  3. Initial ISEE magnetometer results: shock observation

    International Nuclear Information System (INIS)

    Russell, C.T.

    1979-01-01

    ISEE-1 and -2 magnetic field profiles across 6 terrestrial bow shock and one interplanetary shock are examined. The inteplanetary shock illustrates the behavior of a low Mach number shock. Three examples of low or moderate β, high Mach number, quasi-perpendicular shocks are examined. These did not have upstream waves, but rather had waves growing in the field gradient. Two examples of high β shocks showed little coherence in field variation even though the two vehicles were only a few hundred kilometers apart. The authors present the joint behavior of wave, particle and field data across some of these shocks to show some of the myriad of shock features whose behavior they are now beginning to investigate. (Auth.)

  4. Ising antiferromagnet on the Archimedean lattices

    Science.gov (United States)

    Yu, Unjong

    2015-06-01

    Geometric frustration effects were studied systematically with the Ising antiferromagnet on the 11 Archimedean lattices using the Monte Carlo methods. The Wang-Landau algorithm for static properties (specific heat and residual entropy) and the Metropolis algorithm for a freezing order parameter were adopted. The exact residual entropy was also found. Based on the degree of frustration and dynamic properties, ground states of them were determined. The Shastry-Sutherland lattice and the trellis lattice are weakly frustrated and have two- and one-dimensional long-range-ordered ground states, respectively. The bounce, maple-leaf, and star lattices have the spin ice phase. The spin liquid phase appears in the triangular and kagome lattices.

  5. Critical behavior of ferromagnetic Ising thin films

    International Nuclear Information System (INIS)

    Cossio, P.; Mazo-Zuluaga, J.; Restrepo, J.

    2006-01-01

    In the present work, we study the magnetic properties and critical behavior of simple cubic ferromagnetic thin films. We simulate LxLxd films with semifree boundary conditions on the basis of the Monte Carlo method and the Ising model with nearest neighbor interactions. A Metropolis dynamics was implemented to carry out the energy minimization process. For different film thickness, in the nanometer range, we compute the temperature dependence of the magnetization, the magnetic susceptibility and the fourth order Binder's cumulant. Bulk and surface contributions of these quantities are computed in a differentiated fashion. Additionally, according to finite size scaling theory, we estimate the critical exponents for the correlation length, magnetic susceptibility, and magnetization. Results reveal a strong dependence of critical temperature and critical exponents on the film thickness. The obtained critical exponents are finally compared to those reported in literature for thin films

  6. On Ising - Onsager problem in external magnetic field

    International Nuclear Information System (INIS)

    Kochmanski, M.S.

    1997-01-01

    In this paper a new approach to solving the Ising - Onsager problem in external magnetic field is investigated. The expression for free energy on one Ising spin in external field both for the two dimensional and three dimensional Ising model with interaction of the nearest neighbors are derived. The representations of free energy being expressed by multidimensional integrals of Gauss type with the appropriate dimensionality are shown. Possibility of calculating the integrals and the critical indices on the base of the derived representations for free energy is investigated

  7. Developing systems engineers

    CSIR Research Space (South Africa)

    Goncalves, D

    2008-07-01

    Full Text Available will have rendered him incapable of dealing with the majority of problems that will face him.” (Quoted in [12]). UP has applied the SPICES model, proposed by Harden et al. [12], for developing their medical curriculum. Some aspects of the model... are useful to developing systems engineers and will be considered in SE terms at a relevant level of detail. The SPICES model is contrasted against traditional medical curriculum approaches in TABLE 1. These are two extremes on a continuum. Traditional...

  8. Mobile systems development

    DEFF Research Database (Denmark)

    Hosbond, Jens Henrik

    2005-01-01

    and how are they dealt with? Analysis of the empirical data is done following a structured and inductive approach. A framework showing the segmentation of the mobile industry into five layers is proposed and challenges are presented according to two dimensions, namely a business dimension......This paper takes a systems development perspective on mobility, building on preliminary findings of an on-going multiple case study covering 7 companies. The questions driving this paper are: What are the challenges facing development practice in the mobile industry, how do they affect practice...

  9. Linking market interaction intensity of 3D Ising type financial model with market volatility

    Science.gov (United States)

    Fang, Wen; Ke, Jinchuan; Wang, Jun; Feng, Ling

    2016-11-01

    Microscopic interaction models in physics have been used to investigate the complex phenomena of economic systems. The simple interactions involved can lead to complex behaviors and help the understanding of mechanisms in the financial market at a systemic level. This article aims to develop a financial time series model through 3D (three-dimensional) Ising dynamic system which is widely used as an interacting spins model to explain the ferromagnetism in physics. Through Monte Carlo simulations of the financial model and numerical analysis for both the simulation return time series and historical return data of Hushen 300 (HS300) index in Chinese stock market, we show that despite its simplicity, this model displays stylized facts similar to that seen in real financial market. We demonstrate a possible underlying link between volatility fluctuations of real stock market and the change in interaction strengths of market participants in the financial model. In particular, our stochastic interaction strength in our model demonstrates that the real market may be consistently operating near the critical point of the system.

  10. Energy efficiency system development

    Science.gov (United States)

    Leman, A. M.; Rahman, K. A.; Chong, Haw Jie; Salleh, Mohd Najib Mohd; Yusof, M. Z. M.

    2017-09-01

    By subjecting to the massive usage of electrical energy in Malaysia, energy efficiency is now one of the key areas of focus in climate change mitigation. This paper focuses on the development of an energy efficiency system of household electrical appliances for residential areas. Distribution of Questionnaires and pay a visit to few selected residential areas are conducted during the fulfilment of the project as well as some advice on how to save energy are shared with the participants. Based on the collected data, the system developed by the UTHM Energy Team is then evaluated from the aspect of the consumers' behaviour in using electrical appliances and the potential reduction targeted by the team. By the end of the project, 60% of the participants had successfully reduced the electrical power consumption set by the UTHM Energy Team. The reasons for whether the success and the failure is further analysed in this project.

  11. Quantum transitions driven by one-bond defects in quantum Ising rings.

    Science.gov (United States)

    Campostrini, Massimo; Pelissetto, Andrea; Vicari, Ettore

    2015-04-01

    We investigate quantum scaling phenomena driven by lower-dimensional defects in quantum Ising-like models. We consider quantum Ising rings in the presence of a bond defect. In the ordered phase, the system undergoes a quantum transition driven by the bond defect between a magnet phase, in which the gap decreases exponentially with increasing size, and a kink phase, in which the gap decreases instead with a power of the size. Close to the transition, the system shows a universal scaling behavior, which we characterize by computing, either analytically or numerically, scaling functions for the low-level energy differences and the two-point correlation function. We discuss the implications of these results for the nonequilibrium dynamics in the presence of a slowly varying parallel magnetic field h, when going across the first-order quantum transition at h=0.

  12. Critical percolation in the slow cooling of the bi-dimensional ferromagnetic Ising model

    Science.gov (United States)

    Ricateau, Hugo; Cugliandolo, Leticia F.; Picco, Marco

    2018-01-01

    We study, with numerical methods, the fractal properties of the domain walls found in slow quenches of the kinetic Ising model to its critical temperature. We show that the equilibrium interfaces in the disordered phase have critical percolation fractal dimension over a wide range of length scales. We confirm that the system falls out of equilibrium at a temperature that depends on the cooling rate as predicted by the Kibble-Zurek argument and we prove that the dynamic growing length once the cooling reaches the critical point satisfies the same scaling. We determine the dynamic scaling properties of the interface winding angle variance and we show that the crossover between critical Ising and critical percolation properties is determined by the growing length reached when the system fell out of equilibrium.

  13. Environmental Control System Development

    Science.gov (United States)

    Flores Arroyo, Elvin A.

    2018-01-01

    Since before the first men landed on the moon, human beings have aspired to reach farther into space, to discover and answer the great mysteries that exist beyond imagination. To reach where no one has gone before. To able to see all the wonderful things that can be found in space and that only satellites have revealed to us during all this time. Considering the last trip to the moon, mankind has been evolving and improving their technology to reach destinations whose distances had been impossible to transit. To reach that goal, the National Aeronautics and Space Administration (NASA) has designed and developed the largest and most powerful rocket ever created by the human race, the Space Launch System - better known as the SLS. To be able to send this large rocket to space, Kennedy Space Center (KSC) is doing upgrades to their existing facilities and equipment. At Launch Pad 39B, they are setting up a new Environmental Control System (ECS) developed to supply the rocket with the correct gases and mixtures that will be needed for the rocket to launch. The ECS is similar to an air conditioning unit. The main functionality of it is to supply the SLS with the correct gas mixture for it to launch. Also the ECS has been required to reduce or eliminate the possibility of a complete system failure. The system is part of the Ground Support Equipment (GSE) for the SLS that will be going to the Moon and Mars.

  14. Particles and scaling for lattice fields and Ising models

    International Nuclear Information System (INIS)

    Glimm, J.; Jaffe, A.

    1976-01-01

    The conjectured inequality GAMMA 6 4 -fields and the scaling limit for d-dimensional Ising models. Assuming GAMMA 6 = 6 these phi 4 fields are free fields unless the field strength renormalization Z -1 diverges. (orig./BJ) [de

  15. An Ising model for metal-organic frameworks

    Science.gov (United States)

    Höft, Nicolas; Horbach, Jürgen; Martín-Mayor, Victor; Seoane, Beatriz

    2017-08-01

    We present a three-dimensional Ising model where lines of equal spins are frozen such that they form an ordered framework structure. The frame spins impose an external field on the rest of the spins (active spins). We demonstrate that this "porous Ising model" can be seen as a minimal model for condensation transitions of gas molecules in metal-organic frameworks. Using Monte Carlo simulation techniques, we compare the phase behavior of a porous Ising model with that of a particle-based model for the condensation of methane (CH4) in the isoreticular metal-organic framework IRMOF-16. For both models, we find a line of first-order phase transitions that end in a critical point. We show that the critical behavior in both cases belongs to the 3D Ising universality class, in contrast to other phase transitions in confinement such as capillary condensation.

  16. The ising model on the dynamical triangulated random surface

    International Nuclear Information System (INIS)

    Aleinov, I.D.; Migelal, A.A.; Zmushkow, U.V.

    1990-01-01

    The critical properties of Ising model on the dynamical triangulated random surface embedded in D-dimensional Euclidean space are investigated. The strong coupling expansion method is used. The transition to thermodynamical limit is performed by means of continuous fractions

  17. The Ising model coupled to 2d orders

    Science.gov (United States)

    Glaser, Lisa

    2018-04-01

    In this article we make first steps in coupling matter to causal set theory in the path integral. We explore the case of the Ising model coupled to the 2d discrete Einstein Hilbert action, restricted to the 2d orders. We probe the phase diagram in terms of the Wick rotation parameter β and the Ising coupling j and find that the matter and the causal sets together give rise to an interesting phase structure. The couplings give rise to five different phases. The causal sets take on random or crystalline characteristics as described in Surya (2012 Class. Quantum Grav. 29 132001) and the Ising model can be correlated or uncorrelated on the random orders and correlated, uncorrelated or anti-correlated on the crystalline orders. We find that at least one new phase transition arises, in which the Ising spins push the causal set into the crystalline phase.

  18. The diluted tri-dimensional spin-one Ising model with crystal field interactions

    International Nuclear Information System (INIS)

    Saber, M.

    1988-09-01

    3D spin-one Ising models with nearest-neighbour ferromagnetic interactions with crystal-field exhibit tricritical behaviour. A new method that applies to a wide class of random systems is used to study the influence of site and bond dilution on this behaviour. We have calculated temperature-crystal-field-concentration phase diagrams and determined, in particular, the influence of dilution on the zero temperature tricritical temperature. (author). 10 refs, 8 figs

  19. The Peierls argument for higher dimensional Ising models

    International Nuclear Information System (INIS)

    Bonati, Claudio

    2014-01-01

    The Peierls argument is a mathematically rigorous and intuitive method to show the presence of a non-vanishing spontaneous magnetization in some lattice models. This argument is typically explained for the D = 2 Ising model in a way which cannot be easily generalized to higher dimensions. The aim of this paper is to present an elementary discussion of the Peierls argument for the general D-dimensional Ising model. (paper)

  20. Study of spin crossover nanoparticles thermal hysteresis using FORC diagrams on an Ising-like model

    International Nuclear Information System (INIS)

    Atitoaie, Alexandru; Tanasa, Radu; Stancu, Alexandru; Enachescu, Cristian

    2014-01-01

    Recent developments in the synthesis and characterization of spin crossover (SCO) nanoparticles and their prospects of switching at molecular level turned these bistable compounds into possible candidates for replacing the materials used in recording media industry for development of solid state pressure and temperature sensors or for bringing contributions in engineering. Compared to bulk samples with the same chemical structure, SCO nanoparticles display different characteristics of the hysteretic and relaxation properties like the shift of the transition temperature towards lower values along with decrease of the hysteresis width with nanoparticles size. Using an Ising-like model with specific boundary conditions within a Monte Carlo procedure, we here reproduce most of the hysteretic properties of SCO nanoparticles by considering the interaction between spin crossover edge molecules and embedding surfactant molecules and we propose a complex analysis concerning the effect of the interactions and sizes during the thermal transition in systems of SCO nanoparticles by using the First Order Reversal Curves diagram method and by comparison with similar effects in mixed crystal systems. - Highlights: • The influence of size effects in spin crossover nanoparticles is analyzed. • The environment shifts the hysteresis loop towards lower temperatures. • First Order Reversal Curves technique is employed. • One determines the distributions of switching temperatures. • One disentangles between kinetics and non-kinetic parts of the hysteresis

  1. Geological disposal system development

    International Nuclear Information System (INIS)

    Kang, Chul Hyung; Kuh, J. E.; Kim, S. K. and others

    2000-04-01

    Spent fuel inventories to be disposed of finally and design base spent fuel were determined. Technical and safety criteria for a geological repository system in Korea were established. Based on the properties of spent PWR and CANDU fuels, seven repository alternatives were developed and the most promising repository option was selected by the pair-wise comparison method from the technology point of view. With this option preliminary conceptual design studies were carried out. Several module, e.g., gap module, congruent release module were developed for the overall assessment code MASCOT-K. The prominent overseas databases such as OECD/NEA FEP list were are fully reviewed and then screened to identify the feasible ones to reflect the Korean geo-hydrological conditions. In addition to this the well known scenario development methods such as PID, RES were reviewed. To confirm the radiological safety of the proposed KAERI repository concept the preliminary PA was pursued. Thermo-hydro-mechanical analysis for the near field of repository were performed to verify thermal and mechanical stability for KAERI repository system. The requirements of buffer material were analyzed, and based on the results, the quantitative functional criteria for buffer material were established. The hydraulic and swelling property, mechanical properties, and thermal conductivity, the organic carbon content, and the evolution of pore water chemistry were investigated. Based on the results, the candidate buffer material was selected

  2. Geological disposal system development

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Chul Hyung; Kuh, J. E.; Kim, S. K. and others

    2000-04-01

    Spent fuel inventories to be disposed of finally and design base spent fuel were determined. Technical and safety criteria for a geological repository system in Korea were established. Based on the properties of spent PWR and CANDU fuels, seven repository alternatives were developed and the most promising repository option was selected by the pair-wise comparison method from the technology point of view. With this option preliminary conceptual design studies were carried out. Several module, e.g., gap module, congruent release module were developed for the overall assessment code MASCOT-K. The prominent overseas databases such as OECD/NEA FEP list were are fully reviewed and then screened to identify the feasible ones to reflect the Korean geo-hydrological conditions. In addition to this the well known scenario development methods such as PID, RES were reviewed. To confirm the radiological safety of the proposed KAERI repository concept the preliminary PA was pursued. Thermo-hydro-mechanical analysis for the near field of repository were performed to verify thermal and mechanical stability for KAERI repository system. The requirements of buffer material were analyzed, and based on the results, the quantitative functional criteria for buffer material were established. The hydraulic and swelling property, mechanical properties, and thermal conductivity, the organic carbon content, and the evolution of pore water chemistry were investigated. Based on the results, the candidate buffer material was selected.

  3. Comment on "Many-body localization in Ising models with random long-range interactions"

    Science.gov (United States)

    Maksymov, Andrii O.; Rahman, Noah; Kapit, Eliot; Burin, Alexander L.

    2017-11-01

    This Comment is dedicated to the investigation of many-body localization in a quantum Ising model with long-range power-law interactions r-α, relevant for a variety of systems ranging from electrons in Anderson insulators to spin excitations in chains of cold atoms. It has earlier been argued [arXiv:cond-mat/0611387 (2005); Phys. Rev. B 91, 094202 (2015), 10.1103/PhysRevB.91.094202] that this model obeys the dimensional constraint suggesting the delocalization of all finite-temperature states in the thermodynamic limit for α ≤2 d in a d -dimensional system. This expectation conflicts with the recent numerical studies of the specific interacting spin model of Li et al. [Phys. Rev. A 94, 063625 (2016), 10.1103/PhysRevA.94.063625]. To resolve this controversy we reexamine the model of Li et al. [Phys. Rev. A 94, 063625 (2016), 10.1103/PhysRevA.94.063625] and demonstrate that the infinite-temperature states there obey the dimensional constraint. The earlier developed scaling theory for the critical system size required for delocalization is extended to small exponents 0 ≤α ≤d . The disagreements between the two works are explained by the nonstandard selection of investigated states in the ordered phase in the work of Li et al. [Phys. Rev. A 94, 063625 (2016)type="doi" specific-use="suppress-display">10.1103/PhysRevA.94.063625].

  4. Frustrated ground state in the metallic Ising antiferromagnet Nd2Ni2In

    Science.gov (United States)

    Sala, G.; Mašková, S.; Stone, M. B.

    2017-10-01

    We used inelastic neutron scattering measurements to examine the intermetallic Ising antiferromagnet Nd2Ni2In . The dynamical structure factor displays a spectrum with multiple crystal field excitations. These crystal field excitations consist of a set of four transitions covering a range of energies between 4 and 80 meV. The spectrum is very sensitive to the temperature, and we observed a softening and a shift in the energies above the transition temperature of the system. The analysis of the crystalline electric field scheme confirms the Ising nature of the spins and their orientation as proposed by previous studies. We characterized Nd2Ni2In as a large moment intermetallic antiferromagnet with the potential to support a geometrically frustrated Shastry-Sutherland lattice.

  5. Power Systems Development Facility

    International Nuclear Information System (INIS)

    1993-06-01

    The objective of the PSDF would be to provide a modular facility which would support the development of advanced, pilot-scale, coal-based power systems and hot gas clean-up components. These pilot-scale components would be designed to be large enough so that the results can be related and projected to commercial systems. The facility would use a modular approach to enhance the flexibility and capability for testing; consequently, overall capital and operating costs when compared with stand-alone facilities would be reduced by sharing resources common to different modules. The facility would identify and resolve technical barrier, as well as-provide a structure for long-term testing and performance assessment. It is also intended that the facility would evaluate the operational and performance characteristics of the advanced power systems with both bituminous and subbituminous coals. Five technology-based experimental modules are proposed for the PSDF: (1) an advanced gasifier module, (2) a fuel cell test module, (3) a PFBC module, (4) a combustion gas turbine module, and (5) a module comprised of five hot gas cleanup particulate control devices. The final module, the PCD, would capture coal-derived ash and particles from both the PFBC and advanced gasifier gas streams to provide for overall particulate emission control, as well as to protect the combustion turbine and the fuel cell

  6. Power Systems Development Facility

    Energy Technology Data Exchange (ETDEWEB)

    None

    2003-07-01

    This report discusses Test Campaign TC12 of the Kellogg Brown & Root, Inc. (KBR) Transport Gasifier train with a Siemens Westinghouse Power Corporation (SW) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Gasifier is an advanced circulating fluidized-bed reactor designed to operate as either a combustor or a gasifier using a particulate control device (PCD). While operating as a gasifier, either air or oxygen can be used as the oxidant. Test run TC12 began on May 16, 2003, with the startup of the main air compressor and the lighting of the gasifier start-up burner. The Transport Gasifier operated until May 24, 2003, when a scheduled outage occurred to allow maintenance crews to install the fuel cell test unit and modify the gas clean-up system. On June 18, 2003, the test run resumed when operations relit the start-up burner, and testing continued until the scheduled end of the run on July 14, 2003. TC12 had a total of 733 hours using Powder River Basin (PRB) subbituminous coal. Over the course of the entire test run, gasifier temperatures varied between 1,675 and 1,850 F at pressures from 130 to 210 psig.

  7. Investigation of phase diagrams for cylindrical Ising nanotube using cellular automata

    Science.gov (United States)

    Astaraki, M.; Ghaemi, M.; Afzali, K.

    2018-05-01

    Recent developments in the field of applied nanoscience and nanotechnology have heightened the need for categorizing various characteristics of nanostructures. In this regard, this paper establishes a novel method to investigate magnetic properties (phase diagram and spontaneous magnetization) of a cylindrical Ising nanotube. Using a two-layer Ising model and the core-shell concept, the interactions within nanotube has been modelled. In the model, both ferromagnetic and antiferromagnetic cases have been considered. Furthermore, the effect of nanotube's length on the critical temperature is investigated. The model has been simulated using cellular automata approach and phase diagrams were constructed for different values of inter- and intra-layer couplings. For the antiferromagnetic case, the possibility of existence of compensation point is observed.

  8. Nonequilibrium two-dimensional Ising model with stationary uphill diffusion

    Science.gov (United States)

    Colangeli, Matteo; Giardinà, Cristian; Giberti, Claudio; Vernia, Cecilia

    2018-03-01

    Usually, in a nonequilibrium setting, a current brings mass from the highest density regions to the lowest density ones. Although rare, the opposite phenomenon (known as "uphill diffusion") has also been observed in multicomponent systems, where it appears as an artificial effect of the interaction among components. We show here that uphill diffusion can be a substantial effect, i.e., it may occur even in single component systems as a consequence of some external work. To this aim we consider the two-dimensional ferromagnetic Ising model in contact with two reservoirs that fix, at the left and the right boundaries, magnetizations of the same magnitude but of opposite signs.We provide numerical evidence that a class of nonequilibrium steady states exists in which, by tuning the reservoir magnetizations, the current in the system changes from "downhill" to "uphill". Moreover, we also show that, in such nonequilibrium setup, the current vanishes when the reservoir magnetization attains a value approaching, in the large volume limit, the magnetization of the equilibrium dynamics, thus establishing a relation between equilibrium and nonequilibrium properties.

  9. Advanced Dewatering Systems Development

    Energy Technology Data Exchange (ETDEWEB)

    R.H. Yoon; G.H. Luttrell

    2008-07-31

    A new fine coal dewatering technology has been developed and tested in the present work. The work was funded by the Solid Fuels and Feedstocks Grand Challenge PRDA. The objective of this program was to 'develop innovative technical approaches to ensure a continued supply of environmentally sound solid fuels for existing and future combustion systems with minimal incremental fuel cost.' Specifically, this solicitation is aimed at developing technologies that can (i) improve the efficiency or economics of the recovery of carbon when beneficiating fine coal from both current production and existing coal slurry impoundments and (ii) assist in the greater utilization of coal fines by improving the handling characteristics of fine coal via dewatering and/or reconstitution. The results of the test work conducted during Phase I of the current project demonstrated that the new dewatering technologies can substantially reduce the moisture from fine coal, while the test work conducted during Phase II successfully demonstrated the commercial viability of this technology. It is believed that availability of such efficient and affordable dewatering technology is essential to meeting the DOE's objectives.

  10. CT-guided radioactive 125I-seed implantation for the treatment of pancreatic carcinoma: a clinical observation of 19 cases

    International Nuclear Information System (INIS)

    Lu Jian; Zheng Yunfeng; Zhang Huan; Wang Zhongmin; Chen Kemin

    2010-01-01

    Objective: To explore the dynamic changes of serum tumor markers after CT-guided radioactive 125 I-seed implantation treatment in patients with pancreatic carcinoma and to assess the therapeutic effectiveness of 125 I-seed implantation. Methods: CT-guided radioactive 125 I-seed implantation was performed in 19 patients with unresectable advanced pancreatic cancer. Treatment planning system was used to reconstruct 3-dimentional images of the tumor, and the quantity and distribution of 125 I-seeds to be implanted were thus determined. Under CT guidance 125 I-seeds were embedded into pancreatic cancer. Before and after the 125 I-seed implantation the levels of serum tumor markers, including CEA, CA19-9 and CA50, were determined by using radioimmunoassay method. The clinical effects were observed and the therapeutic results were statistically analyzed. Results: The pain stared to be relieved 2 to 5 days after implantation. The total effective rate (CR + PR) at one and three months after treatment was 68.42% (13 /19) and 63.16% (12 /19) respectively. One month after 125 I-seed implantation, the levels of serum CEA, CA19-9 and CA50 were significantly different to that determined before implantation in all cases (P 125 I-seed implantation is a safe and effective interventional treatment for advanced pancreatic cancer with reliable short-term result and remarkable pain-relieving effect. Moreover, this therapy can significantly lower the levels of many serum tumor markers, which play some suggestive roles in evaluating the clinical curativeness. (authors)

  11. POWER SYSTEMS DEVELOPMENT FACILITY

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-11-01

    This report discusses test campaign GCT4 of the Kellogg Brown & Root, Inc. (KBR) transport reactor train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The transport reactor is an advanced circulating fluidized-bed reactor designed to operate as either a combustor or a gasifier using one of two possible particulate control devices (PCDs). The transport reactor was operated as a pressurized gasifier during GCT4. GCT4 was planned as a 250-hour test run to continue characterization of the transport reactor using a blend of several Powder River Basin (PRB) coals and Bucyrus limestone from Ohio. The primary test objectives were: Operational Stability--Characterize reactor loop and PCD operations with short-term tests by varying coal-feed rate, air/coal ratio, riser velocity, solids-circulation rate, system pressure, and air distribution. Secondary objectives included the following: Reactor Operations--Study the devolatilization and tar cracking effects from transient conditions during transition from start-up burner to coal. Evaluate the effect of process operations on heat release, heat transfer, and accelerated fuel particle heat-up rates. Study the effect of changes in reactor conditions on transient temperature profiles, pressure balance, and product gas composition. Effects of Reactor Conditions on Synthesis Gas Composition--Evaluate the effect of air distribution, steam/coal ratio, solids-circulation rate, and reactor temperature on CO/CO{sub 2} ratio, synthesis gas Lower Heating Value (LHV), carbon conversion, and cold and hot gas efficiencies. Research Triangle Institute (RTI) Direct Sulfur Recovery Process (DSRP) Testing--Provide syngas in support of the DSRP commissioning. Loop Seal Operations--Optimize loop seal operations and investigate increases to previously achieved maximum solids-circulation rate.

  12. Hexagonal type Ising nanowire with mixed spins: Some dynamic behaviors

    International Nuclear Information System (INIS)

    Kantar, Ersin; Kocakaplan, Yusuf

    2015-01-01

    The dynamic behaviors of a mixed spin (1/2–1) hexagonal Ising nanowire (HIN) with core–shell structure in the presence of a time dependent magnetic field are investigated by using the effective-field theory with correlations based on the Glauber-type stochastic dynamics (DEFT). According to the values of interaction parameters, temperature dependence of the dynamic magnetizations, the hysteresis loop areas and the dynamic correlations are investigated to characterize the nature (first- or second-order) of the dynamic phase transitions (DPTs). Dynamic phase diagrams, including compensation points, are also obtained. Moreover, from the thermal variations of the dynamic total magnetization, the five compensation types can be found under certain conditions, namely the Q-, R-, S-, P-, and N-types. - Highlights: • Dynamic behaviors of mixed spin HIN system are obtained within the EFT. • The system exhibits i, p and nm fundamental phases. • The dynamic phase diagrams are presented in (h, T), (D, T), (Δ S , T) and (r, T) planes. • The dynamic phase diagrams exhibit the dynamic tricritical point (TCP). • Different dynamic compensation types are obtained

  13. Hamiltonian truncation approach to quenches in the Ising field theory

    Directory of Open Access Journals (Sweden)

    T. Rakovszky

    2016-10-01

    Full Text Available In contrast to lattice systems where powerful numerical techniques such as matrix product state based methods are available to study the non-equilibrium dynamics, the non-equilibrium behaviour of continuum systems is much harder to simulate. We demonstrate here that Hamiltonian truncation methods can be efficiently applied to this problem, by studying the quantum quench dynamics of the 1+1 dimensional Ising field theory using a truncated free fermionic space approach. After benchmarking the method with integrable quenches corresponding to changing the mass in a free Majorana fermion field theory, we study the effect of an integrability breaking perturbation by the longitudinal magnetic field. In both the ferromagnetic and paramagnetic phases of the model we find persistent oscillations with frequencies set by the low-lying particle excitations not only for small, but even for moderate size quenches. In the ferromagnetic phase these particles are the various non-perturbative confined bound states of the domain wall excitations, while in the paramagnetic phase the single magnon excitation governs the dynamics, allowing us to capture the time evolution of the magnetisation using a combination of known results from perturbation theory and form factor based methods. We point out that the dominance of low lying excitations allows for the numerical or experimental determination of the mass spectra through the study of the quench dynamics.

  14. Overcoming Uncertainty with Help From Citizens: ISeeChange Case Studies on Urban Flooding, Indoor Heat waves, and Drought to Inform Resilience Efforts, Hazard Mitigation, and Long-term Planning

    Science.gov (United States)

    Drapkin, J. K.; Wagner, L.

    2017-12-01

    When it comes to the impacts of weather and climate, the granular local data and context needed to inform infrastructure decisions, hazard mitigation efforts, and long-term planning can't be scraped from satellites, remote sensing, or radar data. This is particularly the case with respect to the heat inside people's homes, local street flooding, and landscapes historically unaccustomed to drought conditions. ISeeChange is developing tools that empower citizens, scientists, city planners, journalists, and local community groups to collaborate and iteratively fill-in crucial data gaps as conditions change in real time. ISeeChange connects the public with national media, scientists, and data tools that support community dialogue and enable collaborative science and journalism investigations about our changing environment. ISeeChange's app and platform serve as the center of several on- the-ground community pilot initiatives in cities around the country addressing urban heat, flooding, and drought. Results from ISeeChange investigations suggest that indoor temperatures in Harlem are 7-8 degrees hotter than outdoor temperatures at night; some residents in New Orleans may be experiencing the impacts of 5-year-floods on a more regular basis, and droughts don't look or behave the same in different regions, such as New England. Our presentation will focus on pilots in New Orleans, Harlem, and New England, which demonstrate how diverse teams are producing actionable science to inform the design of resilience efforts like real-time indoor heat notification systems, green infrastructure projects to manage stormwater and flooding, and a photographic index of drought.

  15. Quantum-information approach to the Ising model: Entanglement in chains of qubits

    International Nuclear Information System (INIS)

    Stelmachovic, Peter; Buzek, Vladimir

    2004-01-01

    Simple physical interactions between spin-1/2 particles may result in quantum states that exhibit exotic correlations that are difficult to find if one simply explores state spaces of multipartite systems. In particular, we present a detailed investigation of the well-known Ising model of a chain (ring) of spin-1/2 particles (qubits) in a transverse magnetic field. We present explicit expressions for eigenstates of the model Hamiltonian for arbitrary number of spin-1/2 particles in the chain in the standard (computer) basis, and we investigate quantum entanglement between individual qubits. We analyze bipartite as well as multipartite entanglement in the ground state of the model. In particular, we show that bipartite entanglement between pairs of qubits of the Ising chain (measured in terms of a concurrence) as a function of the parameter λ has a maximum around the point λ=1, and it monotonically decreases for large values of λ. We prove that in the limit λ→∞ this state is locally unitary equivalent to an N-partite Greenberger-Horn-Zeilinger state. We also analyze a very specific eigenstate of the Ising Hamiltonian with a zero eigenenergy (we denote this eigenstate as the X-state). This X-state exhibits the 'extreme' entanglement in a sense that an arbitrary subset A of k≤n qubits in the Ising chain composed of N=2n+1 qubits is maximally entangled with the remaining qubits (set B) in the chain. In addition, we prove that by performing a local operation just on the subset B, one can transform the X-state into a direct product of k singlets shared by the parties A and B. This property of the X-state can be utilized for new secure multipartite communication protocols

  16. Magnetoanisotropic spin-triplet Andreev reflection in ferromagnet-Ising superconductor junctions

    Science.gov (United States)

    Lv, Peng; Zhou, Yan-Feng; Yang, Ning-Xuan; Sun, Qing-Feng

    2018-04-01

    We theoretically study the electronic transport through a ferromagnet-Ising superconductor junction. A tight-binding Hamiltonian describing the Ising superconductor is presented. Then by combining the nonequilibrium Green's function method, the expressions of Andreev reflection coefficient and conductance are obtained. A strong magnetoanisotropic spin-triplet Andreev reflection is shown, and the magnetoanisotropic period is π instead of 2 π as in the conventional magnetoanisotropic system. We demonstrate a significant increase of the spin-triplet Andreev reflection for the single-band Ising superconductor. Furthermore, the dependence of the Andreev reflection on the incident energy and incident angle are also investigated. A complete Andreev reflection can occur when the incident energy is equal to the superconducting gap, regardless of the Fermi energy (spin polarization) of the ferromagnet. For the suitable oblique incidence, the spin-triplet Andreev reflection can be strongly enhanced. In addition, the conductance spectroscopies of both zero bias and finite bias are studied, and the influence of gate voltage, exchange energy, and spin-orbit coupling on the conductance spectroscopy are discussed in detail. The conductance exhibits a strong magnetoanisotropy with period π as the Andreev reflection coefficient. When the magnetization direction is parallel to the junction plane, a large conductance peak always emerges at the superconducting gap. This work offers a comprehensive and systematic study of the spin-triplet Andreev reflection and has an underlying application of π -periodic spin valve in spintronics.

  17. Correlation functions of the Ising model and the eight-vertex model

    International Nuclear Information System (INIS)

    Ko, L.F.

    1986-01-01

    Calculations for the two-point correlation functions in the scaling limit for two statistical models are presented. In Part I, the Ising model with a linear defect is studied for T T/sub c/. The transfer matrix method of Onsager and Kaufman is used. The energy-density correlation is given by functions related to the modified Bessel functions. The dispersion expansion for the spin-spin correlation functions are derived. The dominant behavior for large separations at T not equal to T/sub c/ is extracted. It is shown that these expansions lead to systems of Fredholm integral equations. In Part II, the electric correlation function of the eight-vertex model for T < T/sub c/ is studied. The eight vertex model decouples to two independent Ising models when the four spin coupling vanishes. To first order in the four-spin coupling, the electric correlation function is related to a three-point function of the Ising model. This relation is systematically investigated and the full dispersion expansion (to first order in four-spin coupling) is obtained. The results is a new kind of structure which, unlike those of many solvable models, is apparently not expressible in terms of linear integral equations

  18. Direct comparison of quantum and simulated annealing on a fully connected Ising ferromagnet

    Science.gov (United States)

    Wauters, Matteo M.; Fazio, Rosario; Nishimori, Hidetoshi; Santoro, Giuseppe E.

    2017-08-01

    We compare the performance of quantum annealing (QA, through Schrödinger dynamics) and simulated annealing (SA, through a classical master equation) on the p -spin infinite range ferromagnetic Ising model, by slowly driving the system across its equilibrium, quantum or classical, phase transition. When the phase transition is second order (p =2 , the familiar two-spin Ising interaction) SA shows a remarkable exponential speed-up over QA. For a first-order phase transition (p ≥3 , i.e., with multispin Ising interactions), in contrast, the classical annealing dynamics appears to remain stuck in the disordered phase, while we have clear evidence that QA shows a residual energy which decreases towards zero when the total annealing time τ increases, albeit in a rather slow (logarithmic) fashion. This is one of the rare examples where a limited quantum speedup, a speedup by QA over SA, has been shown to exist by direct solutions of the Schrödinger and master equations in combination with a nonequilibrium Landau-Zener analysis. We also analyze the imaginary-time QA dynamics of the model, finding a 1 /τ2 behavior for all finite values of p , as predicted by the adiabatic theorem of quantum mechanics. The Grover-search limit p (odd )=∞ is also discussed.

  19. Papers presented at ISES solar world congress 1993 in Budapest, Hungary

    International Nuclear Information System (INIS)

    1993-09-01

    Papers presented at the ISES Solar World Congress 1993 by researchers employed at the Thermal Insulation Laboratory at the Technical University of Denmark. The subjects dealt with are: the design of small domestic hot water low-flow solar heating systems, heat storage for large low-flow solar heating systems, the monitoring of Danish marketed solar heating systems, conversion of indoor measurements to outdoor long term performances for low flow solar collectors, optimum ventilation rate of solar collectors, the construction of seasonal heat storage based on a pit with clay membrane, a solar house with a new solar collector, and a framing system for solar wall glazings. (AB)

  20. An extended chain Ising model and its Glauber dynamics

    International Nuclear Information System (INIS)

    Zhao Xing-Yu; Fan Xiao-Hui; Huang Yi-Neng; Huang Xin-Ru

    2012-01-01

    It was first proposed that an extended chain Ising (ECI) model contains the Ising chain model, single spin double-well potentials and a pure phonon heat bath of a specific energy exchange with the spins. The extension method is easy to apply to high dimensional cases. Then the single spin-flip probability (rate) of the ECI model is deduced based on the Boltzmann principle and general statistical principles of independent events and the model is simplified to an extended chain Glauber—Ising (ECGI) model. Moreover, the relaxation dynamics of the ECGI model were simulated by the Monte Carlo method and a comparison with the predictions of the special chain Glauber—Ising (SCGI) model was presented. It was found that the results of the two models are consistent with each other when the Ising chain length is large enough and temperature is relative low, which is the most valuable case of the model applications. These show that the ECI model will provide a firm physical base for the widely used single spin-flip rate proposed by Glauber and a possible route to obtain the single spin-flip rate of other form and even the multi-spin-flip rate. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  1. Excited TBA equations I: Massive tricritical Ising model

    International Nuclear Information System (INIS)

    Pearce, Paul A.; Chim, Leung; Ahn, Changrim

    2001-01-01

    We consider the massive tricritical Ising model M(4,5) perturbed by the thermal operator phi (cursive,open) Greek 1,3 in a cylindrical geometry and apply integrable boundary conditions, labelled by the Kac labels (r,s), that are natural off-critical perturbations of known conformal boundary conditions. We derive massive thermodynamic Bethe ansatz (TBA) equations for all excitations by solving, in the continuum scaling limit, the TBA functional equation satisfied by the double-row transfer matrices of the A 4 lattice model of Andrews, Baxter and Forrester (ABF) in Regime III. The complete classification of excitations, in terms of (m,n) systems, is precisely the same as at the conformal tricritical point. Our methods also apply on a torus but we first consider (r,s) boundaries on the cylinder because the classification of states is simply related to fermionic representations of single Virasoro characters χ r,s (q). We study the TBA equations analytically and numerically to determine the conformal UV and free particle IR spectra and the connecting massive flows. The TBA equations in Regime IV and massless RG flows are studied in Part II

  2. Phase transition in Ising, XY and Heisenberg magnetic films

    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, Route Sidi Bouzid - BP 63 46000 Safi (Morocco); LMPHE, Faculte des Sciences, Universite Mohamed V, Rabat (Morocco); Hamedoun, M. [Institute for Nanomaterials and Nanotechnologies, Rabat (Morocco); Academie Hassan II des Sciences et Techniques, Rabat (Morocco); Benyoussef, A. [LMPHE, Faculte des Sciences, Universite Mohamed V, Rabat (Morocco); Institute for Nanomaterials and Nanotechnologies, Rabat (Morocco); Academie Hassan II des Sciences et Techniques, Rabat (Morocco)

    2012-01-01

    The phase transition and magnetic properties of a ferromagnet spin-S, a disordered diluted thin and semi-infinite film with a face-centered cubic lattice are investigated using the high-temperature series expansions technique extrapolated with Pade approximants method for Heisenberg, XY and Ising models. The reduced critical temperature of the system {tau}{sub c} is studied as function of the thickness of the thin film and the exchange interactions in the bulk, and within the surfaces J{sub b}, J{sub s} and J{sub Up-Tack }, respectively. It is found that {tau}{sub c} increases with the exchange interactions of surface. The magnetic phase diagrams ({tau}{sub c} versus the dilution x) and the percolation threshold are obtained. The shifts of the critical temperatures T{sub c}(l) from the bulk value (T{sub c}({infinity})/T{sub c}(l) - 1) can be described by a power law l{sup -{lambda}}, where {lambda} = 1/{upsilon} is the inverse of the correlation length exponent.

  3. Two dimensional kicked quantum Ising model: dynamical phase transitions

    International Nuclear Information System (INIS)

    Pineda, C; Prosen, T; Villaseñor, E

    2014-01-01

    Using an efficient one and two qubit gate simulator operating on graphical processing units, we investigate ergodic properties of a quantum Ising spin 1/2 model on a two-dimensional lattice, which is periodically driven by a δ-pulsed transverse magnetic field. We consider three different dynamical properties: (i) level density, (ii) level spacing distribution of the Floquet quasienergy spectrum, and (iii) time-averaged autocorrelation function of magnetization components. Varying the parameters of the model, we found transitions between ordered (non-ergodic) and quantum chaotic (ergodic) phases, but the transitions between flat and non-flat spectral density do not correspond to transitions between ergodic and non-ergodic local observables. Even more surprisingly, we found good agreement of level spacing distribution with the Wigner surmise of random matrix theory for almost all values of parameters except where the model is essentially non-interacting, even in regions where local observables are not ergodic or where spectral density is non-flat. These findings question the versatility of the interpretation of level spacing distribution in many-body systems and stress the importance of the concept of locality. (paper)

  4. Upstream waves simultaneously observed by ISEE and UKS

    International Nuclear Information System (INIS)

    Russell, C.T.; Luhmann, J.G.; Elphic, R.C.; Southwood, D.J.; Smith, M.F.; Johnstone, A.D.

    1987-01-01

    Measurements obtained in the solar wind by ISEE-2 and the United Kingdom Subsatellite (UKS) have been examined for observations of upstream waves. These data reveal that the waves in the foreshock region are enhanced at all frequencies from at least 0.003 Hz to 0.5 Hz. The wave spectra generally have a spectral peak, but this peak is usually broad and the peak frequency depends on the position of the spacecraft. Generally, the spectra seen at the two spacecraft are most similar at high frequencies and least similar at low frequencies. The geometry of the interaction is displayed in the plane containing the magnetic field, the solar wind velocity, and the spacecraft location. However, this coordinate system does not order all the observed wave properties. It does not clearly explain or order the handedness of the waves, or their direction of propagation. It is clear that the upstream region is inherently three-dimensional. The position-dependent nature of the upstream waves indicates that comparisons between ground-based measurements and in-situ observations must be undertaken with some caution

  5. Ising percolation in a three-state majority vote model

    Science.gov (United States)

    Balankin, Alexander S.; Martínez-Cruz, M. A.; Gayosso Martínez, Felipe; Mena, Baltasar; Tobon, Atalo; Patiño-Ortiz, Julián; Patiño-Ortiz, Miguel; Samayoa, Didier

    2017-02-01

    In this Letter, we introduce a three-state majority vote model in which each voter adopts a state of a majority of its active neighbors, if exist, but the voter becomes uncommitted if its active neighbors are in a tie, or all neighbors are the uncommitted. Numerical simulations were performed on square lattices of different linear size with periodic boundary conditions. Starting from a random distribution of active voters, the model leads to a stable non-consensus state in which three opinions coexist. We found that the "magnetization" of the non-consensus state and the concentration of uncommitted voters in it are governed by an initial composition of system and are independent of the lattice size. Furthermore, we found that a configuration of the stable non-consensus state undergoes a second order percolation transition at a critical concentration of voters holding the same opinion. Numerical simulations suggest that this transition belongs to the same universality class as the Ising percolation. These findings highlight the effect of an updating rule for a tie between voter neighbors on the critical behavior of models obeying the majority vote rule whenever a strict majority exists.

  6. Reconstructing the Hopfield network as an inverse Ising problem

    International Nuclear Information System (INIS)

    Huang Haiping

    2010-01-01

    We test four fast mean-field-type algorithms on Hopfield networks as an inverse Ising problem. The equilibrium behavior of Hopfield networks is simulated through Glauber dynamics. In the low-temperature regime, the simulated annealing technique is adopted. Although performances of these network reconstruction algorithms on the simulated network of spiking neurons are extensively studied recently, the analysis of Hopfield networks is lacking so far. For the Hopfield network, we found that, in the retrieval phase favored when the network wants to memory one of stored patterns, all the reconstruction algorithms fail to extract interactions within a desired accuracy, and the same failure occurs in the spin-glass phase where spurious minima show up, while in the paramagnetic phase, albeit unfavored during the retrieval dynamics, the algorithms work well to reconstruct the network itself. This implies that, as an inverse problem, the paramagnetic phase is conversely useful for reconstructing the network while the retrieval phase loses all the information about interactions in the network except for the case where only one pattern is stored. The performances of algorithms are studied with respect to the system size, memory load, and temperature; sample-to-sample fluctuations are also considered.

  7. Evaluation of tranche in securitization and long-range Ising model

    Science.gov (United States)

    Kitsukawa, K.; Mori, S.; Hisakado, M.

    2006-08-01

    This econophysics work studies the long-range Ising model of a finite system with N spins and the exchange interaction J/N and the external field H as a model for homogeneous credit portfolio of assets with default probability Pd and default correlation ρd. Based on the discussion on the (J,H) phase diagram, we develop a perturbative calculation method for the model and obtain explicit expressions for Pd,ρd and the normalization factor Z in terms of the model parameters N and J,H. The effect of the default correlation ρd on the probabilities P(Nd,ρd) for Nd defaults and on the cumulative distribution function D(i,ρd) are discussed. The latter means the average loss rate of the“tranche” (layered structure) of the securities (e.g. CDO), which are synthesized from a pool of many assets. We show that the expected loss rate of the subordinated tranche decreases with ρd and that of the senior tranche increases linearly, which are important in their pricing and ratings.

  8. Finite-range-scaling analysis of metastability in an Ising model with long-range interactions

    International Nuclear Information System (INIS)

    Gorman, B.M.; Rikvold, P.A.; Novotny, M.A.

    1994-01-01

    We apply both a scalar field theory and a recently developed transfer-matrix method to study the stationary properties of metastability in a two-state model with weak, long-range interactions: the Nx∞ quasi-one-dimensional Ising model. Using the field theory, we find the analytic continuation f of the free energy across the first-order transition, assuming that the system escapes the metastable state by the nucleation of noninteracting droplets. We find that corrections to the field dependence are substantial, and, by solving the Euler-Lagrange equation for the model numerically, we have verified the form of the free-energy cost of nucleation, including the first correction. In the transfer-matrix method, we associate with the subdominant eigenvectors of the transfer matrix a complex-valued ''constrained'' free-energy density f α computed directly from the matrix. For the eigenvector with an associated magnetization most strongly opposed to the applied magnetic field, f α exhibits finite-range scaling behavior in agreement with f over a wide range of temperatures and fields, extending nearly to the classical spinodal. Some implications of these results for numerical studies of metastability are discussed

  9. Ordering phenomena in a heterostructure of frustrated and unfrustrated triangular-lattice Ising layers

    Science.gov (United States)

    Žukovič, Milan; Tomita, Yusuke; Kamiya, Y.

    2017-07-01

    We study critical and magnetic properties of a bilayer Ising system consisting of two triangular planes A and B, with the antiferromagnetic (AF) coupling JA and the ferromagnetic (FM) one JB for the respective layers, which are coupled by the interlayer interaction JAB by using Monte Carlo simulations. When JA and JB are of the same order, the unfrustrated FM plane orders first at a high temperature Tc 1˜JB . The spontaneous FM order then exerts influence on the other frustrated AF plane as an effective magnetic field, which subsequently induces a ferrimagnetic order in this plane at low temperatures below Tc 2. When short-range order is developed in the AF plane while the influence of the FM plane is still small, there appears a preemptive Berezinskii-Kosterlitz-Thouless-type pseudocritical crossover regime just above the ferrimagnetic phase transition point, where the short-distance behavior up to a rather large length scale exponentially diverging in ∝JA/T is controlled by a line of Gaussian fixed points at T =0 . In the crossover region, a continuous variation in the effective critical exponent 4/9 ≲ηeff≲1/2 is observed. The phase diagram by changing the ratio JA/JB is also investigated.

  10. New developments in the theoretical treatment of low dimensional strongly correlated systems.

    Science.gov (United States)

    James, Andrew J A; Konik, Robert M; Lecheminant, Philippe; Robinson, Neil; Tsvelik, Alexei M

    2017-10-09

    We review two important non-perturbative approaches for extracting the physics of low- dimensional strongly correlated quantum systems. Firstly, we start by providing a comprehensive review of non-Abelian bosonization. This includes an introduction to the basic elements of confor- mal field theory as applied to systems with a current algebra, and we orient the reader by presenting a number of applications of non-Abelian bosonization to models with large symmetries. We then tie this technique into recent advances in the ability of cold atomic systems to realize complex symme- tries. Secondly, we discuss truncated spectrum methods for the numerical study of systems in one and two dimensions. For one-dimensional systems we provide the reader with considerable insight into the methodology by reviewing canonical applications of the technique to the Ising model (and its variants) and the sine-Gordon model. Following this we review recent work on the development of renormalization groups, both numerical and analytical, that alleviate the effects of truncating the spectrum. Using these technologies, we consider a number of applications to one-dimensional systems: properties of carbon nanotubes, quenches in the Lieb-Liniger model, 1+1D quantum chro- modynamics, as well as Landau-Ginzburg theories. In the final part we move our attention to consider truncated spectrum methods applied to two-dimensional systems. This involves combining truncated spectrum methods with matrix product state algorithms. We describe applications of this method to two-dimensional systems of free fermions and the quantum Ising model, including their non-equilibrium dynamics. © 2017 IOP Publishing Ltd.

  11. Conformal Invariance in the Long-Range Ising Model

    CERN Document Server

    Paulos, Miguel F; van Rees, Balt C; Zan, Bernardo

    2016-01-01

    We consider the question of conformal invariance of the long-range Ising model at the critical point. The continuum description is given in terms of a nonlocal field theory, and the absence of a stress tensor invalidates all of the standard arguments for the enhancement of scale invariance to conformal invariance. We however show that several correlation functions, computed to second order in the epsilon expansion, are nontrivially consistent with conformal invariance. We proceed to give a proof of conformal invariance to all orders in the epsilon expansion, based on the description of the long-range Ising model as a defect theory in an auxiliary higher-dimensional space. A detailed review of conformal invariance in the d-dimensional short-range Ising model is also included and may be of independent interest.

  12. Conformal invariance in the long-range Ising model

    Directory of Open Access Journals (Sweden)

    Miguel F. Paulos

    2016-01-01

    Full Text Available We consider the question of conformal invariance of the long-range Ising model at the critical point. The continuum description is given in terms of a nonlocal field theory, and the absence of a stress tensor invalidates all of the standard arguments for the enhancement of scale invariance to conformal invariance. We however show that several correlation functions, computed to second order in the epsilon expansion, are nontrivially consistent with conformal invariance. We proceed to give a proof of conformal invariance to all orders in the epsilon expansion, based on the description of the long-range Ising model as a defect theory in an auxiliary higher-dimensional space. A detailed review of conformal invariance in the d-dimensional short-range Ising model is also included and may be of independent interest.

  13. Conformal invariance in the long-range Ising model

    Energy Technology Data Exchange (ETDEWEB)

    Paulos, Miguel F. [CERN, Theory Group, Geneva (Switzerland); Rychkov, Slava, E-mail: slava.rychkov@lpt.ens.fr [CERN, Theory Group, Geneva (Switzerland); Laboratoire de Physique Théorique de l' École Normale Supérieure (LPTENS), Paris (France); Faculté de Physique, Université Pierre et Marie Curie (UPMC), Paris (France); Rees, Balt C. van [CERN, Theory Group, Geneva (Switzerland); Zan, Bernardo [Institute of Physics, Universiteit van Amsterdam, Amsterdam (Netherlands)

    2016-01-15

    We consider the question of conformal invariance of the long-range Ising model at the critical point. The continuum description is given in terms of a nonlocal field theory, and the absence of a stress tensor invalidates all of the standard arguments for the enhancement of scale invariance to conformal invariance. We however show that several correlation functions, computed to second order in the epsilon expansion, are nontrivially consistent with conformal invariance. We proceed to give a proof of conformal invariance to all orders in the epsilon expansion, based on the description of the long-range Ising model as a defect theory in an auxiliary higher-dimensional space. A detailed review of conformal invariance in the d-dimensional short-range Ising model is also included and may be of independent interest.

  14. New relation for critical exponents in the Ising model

    International Nuclear Information System (INIS)

    Pishtshev, A.

    2007-01-01

    The Ising model in a transverse field is considered at T=0. From the analysis of the power low behaviors of the energy gap and the order parameter as functions of the field a new relation between the respective critical exponents, β>=1/(8s 2 ), is derived. By using the Suzuki equivalence from this inequality a new relation for critical exponents in the Ising model, β>=1/(8ν 2 ), is obtained. A number of numerical examples for different cases illustrates the generality and validity of the relation. By applying this relation the estimation ν=(1/4) 1/3 ∼0.62996 for the 3D-Ising model is proposed

  15. The phase diagrams of the site-diluted spin-1/2 Ising superlattice

    International Nuclear Information System (INIS)

    Saber, A.; Essaoudi, I.; Ainane, A.; Dujardin, F.; Saber, M.; Stebe, B.

    1998-08-01

    Using the effective field theory with a probability distribution technique that accounts for the single-site spin correlations, the critical behavior of a diluted spin-1/2 Ising superlattice consisting of two different ferromagnet materials is examined. The critical temperature of the system is studied as a function of the thickness of the constituents in a unit cell, the concentration of magnetic atoms, and the exchange interactions in each material. It is shown that the properties of the diluted system are different from those of the corresponding pure system. (author)

  16. Universal amplitude ratios in the 3D Ising model

    International Nuclear Information System (INIS)

    Caselle, M.; Hasenbusch, M.

    1998-01-01

    We present a high precision Monte Carlo study of various universal amplitude ratios of the three dimensional Ising spin model. Using state of the art simulation techniques we studied the model close to criticality in both phases. Great care was taken to control systematic errors due to finite size effects and correction to scaling terms. We obtain C + /C - =4.75(3), f +,2nd /f -,2nd =1.95(2) and u * =14.3(1). Our results are compatible with those obtained by field theoretic methods applied to the φ 4 theory and high and low temperature series expansions of the Ising model. (orig.)

  17. Bona Fide Thermodynamic Temperature in Nonequilibrium Kinetic Ising Models

    OpenAIRE

    Sastre, Francisco; Dornic, Ivan; Chaté, Hugues

    2003-01-01

    We show that a nominal temperature can be consistently and uniquely defined everywhere in the phase diagram of large classes of nonequilibrium kinetic Ising spin models. In addition, we confirm the recent proposal that, at critical points, the large-time ``fluctuation-dissipation ratio'' $X_\\infty$ is a universal amplitude ratio and find in particular $X_\\infty \\approx 0.33(2)$ and $X_\\infty = 1/2$ for the magnetization in, respectively, the two-dimensional Ising and voter universality classes.

  18. Zeros of the partition function for some generalized Ising models

    International Nuclear Information System (INIS)

    Dunlop, F.

    1981-01-01

    The author considers generalized Ising Models with two and four body interactions in a complex external field h such that Re h>=mod(Im h) + C, where C is an explicit function of the interaction parameters. The partition function Z(h) is then shown to satisfy mod(Z(h))>=Z(c), so that the pressure is analytic in h inside the given region. The method is applied to specific examples: the gauge invariant Ising Model, and the Widom Rowlinson model on the lattice. (Auth.)

  19. Decoherence in a dynamical quantum phase transition of the transverse Ising chain

    International Nuclear Information System (INIS)

    Mostame, Sarah; Schaller, Gernot; Schuetzhold, Ralf

    2007-01-01

    For the prototypical example of the Ising chain in a transverse field, we study the impact of decoherence on the sweep through a second-order quantum phase transition. Apart from the advance in the general understanding of the dynamics of quantum phase transitions, these findings are relevant for adiabatic quantum algorithms due to the similarities between them. It turns out that (in contrast to first-order transitions studied previously) the impact of decoherence caused by a weak coupling to a rather general environment increases with system size (i.e., number of spins or qubits), which might limit the scalability of the system

  20. The ferromagnet spin-1/2 Ising superlattice in a transverse field

    International Nuclear Information System (INIS)

    Bouziane, T.; Saber, M.; Belaaraj, A.; Ainane, A.

    1998-09-01

    The phase transitions of a ferromagnet spin-1/2 Ising superlattice consisting of two different materials in a transverse field is examined with the use of effective field theory that accounts for the self-spin function correlation. The critical temperature of the system is studied as a function of the thickness of the constituents in a unit cell and of exchange interactions in each material. A critical interface exchange interaction above which the interface magnetism appears is found. The effects of a uniform transverse field and the interface exchange interaction on the parameters of the system are also investigated. (author)

  1. Light induced kickoff of magnetic domain walls in Ising chains

    Science.gov (United States)

    Bogani, Lapo

    2012-02-01

    Controlling the speed at which systems evolve is a challenge shared by all disciplines, and otherwise unrelated areas use common theoretical frameworks towards this goal. A particularly widespread model is Glauber dynamics, which describes the time evolution of the Ising model and can be applied to any binary system. Here we show, using molecular nanowires under irradiation, that Glauber dynamics can be controlled by a novel domain-wall kickoff mechanism. Contrary to known processes, the kickoff has unambiguous fingerprints, slowing down the spin-flip attempt rate by several orders of magnitude, and following a scaling law. The required irradiation power is very low, a substantial improvement over present methods of magnetooptical switching: in our experimental demonstration we switched molecular nanowires with light, using powers thousands of times lower than in previous optical switching methods. This manipulation of stochastic dynamic processes is extremely clean, leading to fingerprint signatures and scaling laws. These observations can be used, in material science, to better study domain-wall displacements and solitons in discrete lattices. These results provide a new way to control and study stochastic dynamic processes. Being general for Glauber dynamics, they can be extended to different kinds of magnetic nanowires and to a myriad of fields, ranging from social evolution to neural networks and chemical reactivity. For nanoelectronics and molecular spintronics the kickoff affords external control of molecular spin-valves and a magnetic fingerprint in single molecule measurements. It can also be applied to the dynamics of mechanical switches and the related study of phasons and order-disorder transitions.

  2. Factors Affecting Stock Returns of Firms Quoted in ISE Market: A Dynamic Panel Data Approach

    Directory of Open Access Journals (Sweden)

    Şebnem Er

    2013-07-01

    Full Text Available Several studies, explaining the factors affecting stock returns, have been published both in developed and developing countries. In many of these papers, either cross-sectional or time series methods have been applied. In this study, Dynamic Panel Data Analysis Methods have been conducted to explain the factors affecting stock returns of 64 manufacturing firms that are continuously quoted in ISE during the period of 2003-2007. The results indicate that stock performance, financial structure, activity and profitability ratios can be used to explain the stock returns as well as the oil prices, economic growth, exchange rate, interest rate, and money supply.

  3. Framework for control system development

    International Nuclear Information System (INIS)

    Cork, C.; Nishimura, Hiroshi

    1992-01-01

    Control systems being developed for the present generation of accelerators will need to adapt to changing machine and operating state conditions. Such systems must also be capable of evolving over the life of the accelerator operation. In this paper we present a framework for the development of adaptive control systems

  4. Framework for control system development

    International Nuclear Information System (INIS)

    Cork, C.; Nishimura, Hiroshi.

    1991-11-01

    Control systems being developed for the present generation of accelerators will need to adapt to changing machine and operating state conditions. Such systems must also be capable of evolving over the life of the accelerator operation. In this paper we present a framework for the development of adaptive control systems

  5. Evolutionary Information System Development

    DEFF Research Database (Denmark)

    Kristensen, Jan

    and necessary items that must be taken into account are pointed out by narrating two stories of e-commerce implementation processes in wholesale companies. The empirical evidence suggests the following: Managing the continued development on an operational level requires operational insight and understanding...

  6. Specific heat of the simple-cubic Ising model

    NARCIS (Netherlands)

    Feng, X.; Blöte, H.W.J.

    2010-01-01

    We provide an expression quantitatively describing the specific heat of the Ising model on the simple-cubic lattice in the critical region. This expression is based on finite-size scaling of numerical results obtained by means of a Monte Carlo method. It agrees satisfactorily with series expansions

  7. Commuting quantum circuits and complexity of Ising partition functions

    International Nuclear Information System (INIS)

    Fujii, Keisuke; Morimae, Tomoyuki

    2017-01-01

    Instantaneous quantum polynomial-time (IQP) computation is a class of quantum computation consisting only of commuting two-qubit gates and is not universal. Nevertheless, it has been shown that if there is a classical algorithm that can simulate IQP efficiently, the polynomial hierarchy collapses to the third level, which is highly implausible. However, the origin of the classical intractability is still less understood. Here we establish a relationship between IQP and computational complexity of calculating the imaginary-valued partition functions of Ising models. We apply the established relationship in two opposite directions. One direction is to find subclasses of IQP that are classically efficiently simulatable by using exact solvability of certain types of Ising models. Another direction is applying quantum computational complexity of IQP to investigate (im)possibility of efficient classical approximations of Ising partition functions with imaginary coupling constants. Specifically, we show that a multiplicative approximation of Ising partition functions is #P-hard for almost all imaginary coupling constants even on planar lattices of a bounded degree. (paper)

  8. Correlation effects in the Ising model in an external field

    International Nuclear Information System (INIS)

    Borges, H.E.; Silva, P.R.

    1983-01-01

    The thermodynamic properties of the spin-1/2 Ising Model in an external field are evaluated through the use of the exponential differential operator method and Callen's exact relations. The correlations effects are treated in a phenomenological approach and the results are compared with other treatments. (Author) [pt

  9. The spin S quantum Ising model at T=0

    International Nuclear Information System (INIS)

    Kamieniarz, G.; Kowalewski, L.; Piechocki, W.

    1982-09-01

    The Ising model with a transverse field for a general spin S is investigated within the framework of the Green-function method in the paramagnetic region at T=0. The analysis of selfconsistent equations gives a description of softmode phase transition as well as extrapolated values of critical fields and critical energy gap exponents. (author)

  10. Susceptibility and magnetization of a random Ising model

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, D; Srivastava, V [Roorkee Univ. (India). Dept. of Physics

    1977-08-01

    The susceptibility of a bond disordered Ising model is calculated by configurationally averaging an Ornstein-Zernike type of equation for the two spin correlation function. The equation for the correlation function is derived using a diagrammatic method due to Englert. The averaging is performed using bond CPA. The magnetization is also calculated by averaging in a similar manner a linearised molecular field equation.

  11. The dilute random field Ising model by finite cluster approximation

    International Nuclear Information System (INIS)

    Benyoussef, A.; Saber, M.

    1987-09-01

    Using the finite cluster approximation, phase diagrams of bond and site diluted three-dimensional simple cubic Ising models with a random field have been determined. The resulting phase diagrams have the same general features for both bond and site dilution. (author). 7 refs, 4 figs

  12. Non-Abelian anyons: when Ising meets Fibonacci

    NARCIS (Netherlands)

    Grosfeld, E.; Schoutens, K.

    2009-01-01

    We consider an interface between two non-Abelian quantum Hall states: the Moore-Read state, supporting Ising anyons, and the k=2 non-Abelian spin-singlet state, supporting Fibonacci anyons. It is shown that the interface supports neutral excitations described by a (1+1)-dimensional conformal field

  13. Liferay Portal Systems Development

    CERN Document Server

    Yuan, Jonas X

    2012-01-01

    This book focuses on teaching by example. Every chapter provides an overview, and then dives right into hands-on examples so you can see and play with the solution in your own environment. This book is for Java developers who don't need any prior experience with Liferay portal. Although Liferay portal makes heavy use of open source frameworks, no prior experience of using these is assumed.

  14. Topics in computer simulations of statistical systems

    International Nuclear Information System (INIS)

    Salvador, R.S.

    1987-01-01

    Several computer simulations studying a variety of topics in statistical mechanics and lattice gauge theories are performed. The first study describes a Monte Carlo simulation performed on Ising systems defined on Sierpinsky carpets of dimensions between one and four. The critical coupling and the exponent γ are measured as a function of dimension. The Ising gauge theory in d = 4 - epsilon, for epsilon → 0 + , is then studied by performing a Monte Carlo simulation for the theory defined on fractals. A high statistics Monte Carlo simulation for the three-dimensional Ising model is presented for lattices of sizes 8 3 to 44 3 . All the data obtained agrees completely, within statistical errors, with the forms predicted by finite-sizing scaling. Finally, a method to estimate numerically the partition function of statistical systems is developed

  15. Architecture Approach in System Development

    Directory of Open Access Journals (Sweden)

    Ladislav Burita

    2017-01-01

    Full Text Available The purpose of this paper is to describe a practical solution of architecture approach in system development. The software application is the system which optimizes the transport service. The first part of the paper defines the enterprise architecture, its parts and frameworks. Next is explained the NATO Architecture Framework (NAF, a tool for command and control systems development in military environment. The NAF is used for architecture design of the system for optimization of the transport service.

  16. HLW Disposal System Development

    Energy Technology Data Exchange (ETDEWEB)

    Choi, J. W.; Choi, H. J.; Lee, J. Y. (and others)

    2007-06-15

    A KRS is suggested through design requirement analysis of the buffer and the canister which are the constituent of disposal system engineered barrier and HLW management plans are proposed. In the aspect of radionuclide retention capacity, the thickness of the buffer is determined 0.5m, the shape to be disc and ring and the dry density to be 1.6 g/cm{sup 3}. The maximum temperature of the buffer is below 100 .deg. which meets the design requirement. And bentonite blocks with 5 wt% of graphite showed more than 1.0 W/mK of thermal conductivity without the addition of sand. The result of the thermal analysis for proposed double-layered buffer shows that decrease of 7 .deg. C in maximum temperature of the buffer. For the disposal canister, the copper for the outer shell material and cast iron for the inner structure material is recommended considering the results analyzed in terms of performance of the canisters and manufacturability and the geochemical properties of deep groundwater sampled from the research area with granite, salt water intrusion, and the heavy weight of the canister. The results of safety analysis for the canister shows that the criticality for the normal case including uncertainty is the value of 0.816 which meets subcritical condition. Considering nation's 'Basic Plan for Electric Power Demand and Supply' and based on the scenario of disposing CANDU spent fuels in the first phase, the disposal system that the repository will be excavated in eight phases with the construction of the Underground Research Laboratory (URL) beginning in 2020 and commissioning in 2040 until the closure of the repository is proposed. Since there is close correlation between domestic HLW management plans and front-end/back-end fuel cycle plans causing such a great sensitivity of international environment factor, items related to assuring the non-proliferation and observing the international standard are showed to be the influential factor and acceptability

  17. Surface magnetization of the Ising ferromagnet in semi-infinite cubic lattice: renormalization group approach

    International Nuclear Information System (INIS)

    Chame, A.M.N.; Tsallis, C.

    1988-01-01

    The behaviour of the spontaneous surface and bulk magnetizations as function of the temperature for the Ising ferromagnet in a semi-infinitre cubic lattice for various ratios JS/JB (JS and JB are the surface and bulk coupling constants, respectively), is studied. The extraordinary transition where the surface maintains its magnetization as the bulk disorders, was study, in particular; a discontinuity on the first derivative of the surface magnetization at the bulk transition temperature was found. The criticality of the system (universality classes, critical exponents and amplitudes) is discussed. An unexpected slight lack of monotonicity of the surface magnetization as a function of JS/JB for JS/JB [pt

  18. The Luttinger liquid in superlattice structures: atomic gases, quantum dots and the classical Ising chain

    International Nuclear Information System (INIS)

    Bhattacherjee, Aranya B; Jha, Pradip; Kumar, Tarun; Mohan, Man

    2011-01-01

    We study the physical properties of a Luttinger liquid in a superlattice that is characterized by alternating two tunneling parameters. Using the bosonization approach, we describe the corresponding Hubbard model by the equivalent Tomonaga-Luttinger model. We analyze the spin-charge separation and transport properties of the superlattice system. We suggest that cold Fermi gases trapped in a bichromatic optical lattice and coupled quantum dots offer the opportunity to measure these effects in a convenient manner. We also study the classical Ising chain with two tunneling parameters. We find that the classical two-point correlator decreases as the difference between the two tunneling parameters increases.

  19. Thermodynamic and critical properties of an antiferromagnetically stacked triangular Ising antiferromagnet in a field

    Science.gov (United States)

    Žukovič, M.; Borovský, M.; Bobák, A.

    2018-05-01

    We study a stacked triangular lattice Ising model with both intra- and inter-plane antiferromagnetic interactions in a field, by Monte Carlo simulation. We find only one phase transition from a paramagnetic to a partially disordered phase, which is of second order and 3D XY universality class. At low temperatures we identify two highly degenerate phases: at smaller (larger) fields the system shows long-range ordering in the stacking direction (within planes) but not in the planes (stacking direction). Nevertheless, crossovers to these phases do not have a character of conventional phase transitions but rather linear-chain-like excitations.

  20. Simulations of ground state fluctuations in mean-field Ising spin glasses

    International Nuclear Information System (INIS)

    Boettcher, Stefan

    2010-01-01

    The scaling of fluctuations in the distribution of ground state energies or costs with the system size N for Ising spin glasses is considered using an extensive set of simulations with the extremal optimization heuristic across a range of different models on sparse and dense graphs. These models exhibit very diverse behaviors, and an asymptotic extrapolation is often complicated by higher-order corrections in size. The clearest picture, in fact, emerges from the study of graph bipartitioning, a combinatorial optimization problem closely related to spin glasses. Asides from two-spin interactions with discrete bonds, we also consider problems with Gaussian bonds and three-spin interactions, which behave quite differently

  1. Renormalization group critical frontier of the three-dimensional bond-dilute Ising ferromagnet

    International Nuclear Information System (INIS)

    Chao, N.-C.; Schwaccheim, G.; Tsallis, C.

    1981-01-01

    The critical frontier (as well as the thermal type critical exponents) associated to the quenched bond-dilute spin - 1/2 Ising ferromagnet in the simple cubic lattice is approximately calculated within a real space renormalization group framework in two different versions. Both lead to qualitatively satisfactory critical frontiers, although one of them provides an unphysical fixed point (which seem to be related to the three-dimensionality of the system) besides the expected pure ones; its effects tend to disappear for increasingly large clusters. Through an extrapolation procedure the (unknown) critical frontier is approximately located. (Author) [pt

  2. Heat fluctuations in Ising models coupled with two different heat baths

    Energy Technology Data Exchange (ETDEWEB)

    Piscitelli, A; Gonnella, G [Dipartimento di Fisica, Universita di Bari and Istituto Nazionale di Fisica Nucleare, Sezione di Bari, via Amendola 173, 70126 Bari (Italy); Corberi, F [Dipartimento di Matematica ed Informatica, via Ponte don Melillo, Universita di Salerno, 84084 Fisciano (Italy)

    2008-08-22

    Monte Carlo simulations of Ising models coupled to heat baths at two different temperatures are used to study a fluctuation relation for the heat exchanged between the two thermostats in a time {tau}. Different kinetics (single-spin-flip or spin-exchange Kawasaki dynamics), transition rates (Glauber or Metropolis), and couplings between the system and the thermostats have been considered. In every case the fluctuation relation is verified in the large {tau} limit, both in the disordered and in the low temperature phase. Finite-{tau} corrections are shown to obey a scaling behavior. (fast track communication)

  3. Magnetic properties of mixed spin (1, 3/2) Ising nanoparticles with core–shell structure

    International Nuclear Information System (INIS)

    Deviren, Bayram; Şener, Yunus

    2015-01-01

    The magnetic properties of mixed spin-1 and spin-3/2 Ising nanoparticles with core/shell structure are studied by using the effective-field theory with correlations. We investigate the thermal variations of the core, shell and total magnetizations and the Q-, R-, P-, S-, N- and L-types of compensation behavior in Néel classification nomenclature exists in the system. The effects of the crystal-field, core and shell interactions and interface coupling, on the phase diagrams are investigated in detail and the obtained phase diagrams are presented in three different planes. The system exhibits both second- and first-order phase transitions besides tricritical point, double critical end point, triple point and critical end point depending on the appropriate values of the interaction parameters. The system strongly affected by the surface situations and some characteristic phenomena are found depending on the ratio of the physical parameters in the surface shell and the core. - Highlights: • Magnetic properties of mixed spin (1, 3/2) Ising nanoparticles are investigated. • The system exhibits tricritical, double critical end, triple, critical end points. • Q-, R-, P-, S-, N- and L-types of compensation behavior are found. • Some characteristic phenomena are found depending on the interaction parameters. • Effects of crystal-field and bilinear interactions on the system are examined

  4. Emergent 1d Ising Behavior in AN Elementary Cellular Automaton Model

    Science.gov (United States)

    Kassebaum, Paul G.; Iannacchione, Germano S.

    The fundamental nature of an evolving one-dimensional (1D) Ising model is investigated with an elementary cellular automaton (CA) simulation. The emergent CA simulation employs an ensemble of cells in one spatial dimension, each cell capable of two microstates interacting with simple nearest-neighbor rules and incorporating an external field. The behavior of the CA model provides insight into the dynamics of coupled two-state systems not expressible by exact analytical solutions. For instance, state progression graphs show the causal dynamics of a system through time in relation to the system's entropy. Unique graphical analysis techniques are introduced through difference patterns, diffusion patterns, and state progression graphs of the 1D ensemble visualizing the evolution. All analyses are consistent with the known behavior of the 1D Ising system. The CA simulation and new pattern recognition techniques are scalable (in both dimension, complexity, and size) and have many potential applications such as complex design of materials, control of agent systems, and evolutionary mechanism design.

  5. Magnetic properties of mixed spin (1, 3/2) Ising nanoparticles with core–shell structure

    Energy Technology Data Exchange (ETDEWEB)

    Deviren, Bayram, E-mail: bayram.deviren@nevsehir.edu.tr [Department of Physics, Nevsehir Hacı Bektaş Veli University, 50300 Nevşehir (Turkey); Şener, Yunus [Institute of Science, Department of Physics, Nevsehir Hacı Bektaş Veli University, 50300 Nevşehir (Turkey)

    2015-07-15

    The magnetic properties of mixed spin-1 and spin-3/2 Ising nanoparticles with core/shell structure are studied by using the effective-field theory with correlations. We investigate the thermal variations of the core, shell and total magnetizations and the Q-, R-, P-, S-, N- and L-types of compensation behavior in Néel classification nomenclature exists in the system. The effects of the crystal-field, core and shell interactions and interface coupling, on the phase diagrams are investigated in detail and the obtained phase diagrams are presented in three different planes. The system exhibits both second- and first-order phase transitions besides tricritical point, double critical end point, triple point and critical end point depending on the appropriate values of the interaction parameters. The system strongly affected by the surface situations and some characteristic phenomena are found depending on the ratio of the physical parameters in the surface shell and the core. - Highlights: • Magnetic properties of mixed spin (1, 3/2) Ising nanoparticles are investigated. • The system exhibits tricritical, double critical end, triple, critical end points. • Q-, R-, P-, S-, N- and L-types of compensation behavior are found. • Some characteristic phenomena are found depending on the interaction parameters. • Effects of crystal-field and bilinear interactions on the system are examined.

  6. Development of FAME Animation System

    International Nuclear Information System (INIS)

    Hasegawa, Yukihiro; Hamamatsu, Kiyotaka; Shirai, Hiroshi; Matsuda, Toshiaki; Watanabe, Hideto; Itakura, Hirofumi; Tahata, Yasunori

    1999-02-01

    In order to monitor an animation of magnetohydrodynamic equilibrium calculated by the FAME-II (Fast Analyzer for Magnetohydrodynamic Equilibrium-II) system, a FAME Animation System was developed. This system provides automatically the animation on workstations connected to network with the same period of JT-60U discharge sequence. Then, the system can supply the important information for JT-60U operators to determine control parameters of the succeeding discharge. This report describes the overview of the FAME Animation System. (author)

  7. Development of mini VSAT system

    Science.gov (United States)

    Lu, Shyue-Ching; Chiu, Wu-Jhy; Lin, Hen-Dao; Shih, Mu-Piao

    1992-03-01

    This paper presents the mini VSAT (very small aperture terminal) system, which is a low cost networking system providing economical alternatives to the business world's datacom needs. The system is designed to achieve the highest possible performance/price ratio for private VSAT networks that range from a few tens of remote terminals to large networks of several thousands remote terminals. The paper describes the system architecture, major features, hardware and software structure, access protocol and performance of the developed system.

  8. A theory of solving TAP equations for Ising models with general invariant random matrices

    DEFF Research Database (Denmark)

    Opper, Manfred; Çakmak, Burak; Winther, Ole

    2016-01-01

    We consider the problem of solving TAP mean field equations by iteration for Ising models with coupling matrices that are drawn at random from general invariant ensembles. We develop an analysis of iterative algorithms using a dynamical functional approach that in the thermodynamic limit yields...... the iteration dependent on a Gaussian distributed field only. The TAP magnetizations are stable fixed points if a de Almeida–Thouless stability criterion is fulfilled. We illustrate our method explicitly for coupling matrices drawn from the random orthogonal ensemble....

  9. The Guided System Development Framework

    DEFF Research Database (Denmark)

    Carvalho Quaresma, Jose Nuno; Probst, Christian W.; Nielson, Flemming

    2011-01-01

    The Service-Oriented Computing paradigm has had significant influence on the Internet. With the emergence of this paradigm, it is important to provide tools that help developers designing and verifying such systems. In this article, we present the Guided System Development (GSD) Framework that aids...

  10. Dynamic phase transitions in a cylindrical Ising nanowire under a time-dependent oscillating magnetic field

    International Nuclear Information System (INIS)

    Deviren, Bayram; Kantar, Ersin; Keskin, Mustafa

    2012-01-01

    The dynamic phase transitions in a cylindrical Ising nanowire system under a time-dependent oscillating external magnetic field for both ferromagnetic and antiferromagnetic interactions are investigated within the effective-field theory with correlations and the Glauber-type stochastic dynamics approach. The effective-field dynamic equations for the average longitudinal magnetizations on the surface shell and core are derived by employing the Glauber transition rates. Temperature dependence of the dynamic magnetizations, the dynamic total magnetization, the hysteresis loop areas and the dynamic correlations are investigated in order to characterize the nature (first- or second-order) of the dynamic transitions as well as the dynamic phase transition temperatures and the compensation behaviors. The system strongly affected by the surface situations. Some characteristic phenomena are found depending on the ratio of the physical parameters in the surface shell and the core. According to the values of Hamiltonian parameters, five different types of compensation behaviors in the Néel classification nomenclature exist in the system. The system also exhibits a reentrant behavior. - Highlights: ► The dynamic aspects of a cylindrical Ising nanowire are investigated in detail. ► The dynamic magnetizations, hysteresis loop areas and correlations are calculated. ► We studied both the FM and AFM interactions within the EFT with correlations. ► Some characteristic phenomena are found depending on the interaction parameters. ► We obtained five different types of compensation behaviors and reentrant behavior.

  11. Dynamic phase transitions in a cylindrical Ising nanowire under a time-dependent oscillating magnetic field

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-07-15

    The dynamic phase transitions in a cylindrical Ising nanowire system under a time-dependent oscillating external magnetic field for both ferromagnetic and antiferromagnetic interactions are investigated within the effective-field theory with correlations and the Glauber-type stochastic dynamics approach. The effective-field dynamic equations for the average longitudinal magnetizations on the surface shell and core are derived by employing the Glauber transition rates. Temperature dependence of the dynamic magnetizations, the dynamic total magnetization, the hysteresis loop areas and the dynamic correlations are investigated in order to characterize the nature (first- or second-order) of the dynamic transitions as well as the dynamic phase transition temperatures and the compensation behaviors. The system strongly affected by the surface situations. Some characteristic phenomena are found depending on the ratio of the physical parameters in the surface shell and the core. According to the values of Hamiltonian parameters, five different types of compensation behaviors in the Neel classification nomenclature exist in the system. The system also exhibits a reentrant behavior. - Highlights: Black-Right-Pointing-Pointer The dynamic aspects of a cylindrical Ising nanowire are investigated in detail. Black-Right-Pointing-Pointer The dynamic magnetizations, hysteresis loop areas and correlations are calculated. Black-Right-Pointing-Pointer We studied both the FM and AFM interactions within the EFT with correlations. Black-Right-Pointing-Pointer Some characteristic phenomena are found depending on the interaction parameters. Black-Right-Pointing-Pointer We obtained five different types of compensation behaviors and reentrant behavior.

  12. Testing ground for fluctuation theorems: The one-dimensional Ising model

    Science.gov (United States)

    Lemos, C. G. O.; Santos, M.; Ferreira, A. L.; Figueiredo, W.

    2018-04-01

    In this paper we determine the nonequilibrium magnetic work performed on a Ising model and relate it to the fluctuation theorem derived some years ago by Jarzynski. The basic idea behind this theorem is the relationship connecting the free energy difference between two thermodynamic states of a system and the average work performed by an external agent, in a finite time, through nonequilibrium paths between the same thermodynamic states. We test the validity of this theorem by considering the one-dimensional Ising model where the free energy is exactly determined as a function of temperature and magnetic field. We have found that the Jarzynski theorem remains valid for all the values of the rate of variation of the magnetic field applied to the system. We have also determined the probability distribution function for the work performed on the system for the forward and reverse processes and verified that predictions based on the Crooks relation are equally correct. We also propose a method to calculate the lag between the current state of the system and that of the equilibrium based on macroscopic variables. We have shown that the lag increases with the sweeping rate of the field at its final value for the reverse process, while it decreases in the case of the forward process. The lag increases linearly with the size of the chain and with a slope decreasing with the inverse of the rate of variation of the field.

  13. Accurate Mapping of Multilevel Rydberg Atoms on Interacting Spin-1 /2 Particles for the Quantum Simulation of Ising Models

    Science.gov (United States)

    de Léséleuc, Sylvain; Weber, Sebastian; Lienhard, Vincent; Barredo, Daniel; Büchler, Hans Peter; Lahaye, Thierry; Browaeys, Antoine

    2018-03-01

    We study a system of atoms that are laser driven to n D3 /2 Rydberg states and assess how accurately they can be mapped onto spin-1 /2 particles for the quantum simulation of anisotropic Ising magnets. Using nonperturbative calculations of the pair potentials between two atoms in the presence of electric and magnetic fields, we emphasize the importance of a careful selection of experimental parameters in order to maintain the Rydberg blockade and avoid excitation of unwanted Rydberg states. We benchmark these theoretical observations against experiments using two atoms. Finally, we show that in these conditions, the experimental dynamics observed after a quench is in good agreement with numerical simulations of spin-1 /2 Ising models in systems with up to 49 spins, for which numerical simulations become intractable.

  14. Complex-network description of thermal quantum states in the Ising spin chain

    Science.gov (United States)

    Sundar, Bhuvanesh; Valdez, Marc Andrew; Carr, Lincoln D.; Hazzard, Kaden R. A.

    2018-05-01

    We use network analysis to describe and characterize an archetypal quantum system—an Ising spin chain in a transverse magnetic field. We analyze weighted networks for this quantum system, with link weights given by various measures of spin-spin correlations such as the von Neumann and Rényi mutual information, concurrence, and negativity. We analytically calculate the spin-spin correlations in the system at an arbitrary temperature by mapping the Ising spin chain to fermions, as well as numerically calculate the correlations in the ground state using matrix product state methods, and then analyze the resulting networks using a variety of network measures. We demonstrate that the network measures show some traits of complex networks already in this spin chain, arguably the simplest quantum many-body system. The network measures give insight into the phase diagram not easily captured by more typical quantities, such as the order parameter or correlation length. For example, the network structure varies with transverse field and temperature, and the structure in the quantum critical fan is different from the ordered and disordered phases.

  15. Hysteretic features of Ising-type segmented nanostructure with alternating magnetic wires

    International Nuclear Information System (INIS)

    Kantar, Ersin

    2016-01-01

    In the present study, a theoretical approach to investigate the hysteresis behaviors in segmented nanowires is described and applied to spin-1/2 and spin-1 hexagonal nanowire. The hysteresis loop, coercive field and remanent magnetization of a segmented Ising nanowire (SIN) are obtained by using the effective-field theory with correlations. The effects of the temperature, crystal field and geometrical parameters of nanowires on the hysteresis behaviors of the system are investigated. A number of characteristic behaviors are found, such as the occurrence of single and triple hysteresis loops for appropriate values of the crystal field. The hysteresis behaviors are also strongly dependent on geometrical parameters. Comparisons between the obtained theoretical results and some experimental works of segmented nanowire arrays with hysteresis behaviors are made and a very good agreement is obtained. - Highlights: • The hysteresis behaviors of a segmented Ising nanowire are obtained. • The effective-field theory with correlations are used to calculations. • The effects of the temperature and crystal field on the system are investigated. • The geometrical parameters have a significant effect on the system are observed. • The single and triple loops for appropriate values of the crystal field are obtained.

  16. Data management system advanced development

    Science.gov (United States)

    Douglas, Katherine; Humphries, Terry

    1990-01-01

    The Data Management System (DMS) Advanced Development task provides for the development of concepts, new tools, DMS services, and for the testing of the Space Station DMS hardware and software. It also provides for the development of techniques capable of determining the effects of system changes/enhancements, additions of new technology, and/or hardware and software growth on system performance. This paper will address the built-in characteristics which will support network monitoring requirements in the design of the evolving DMS network implementation, functional and performance requirements for a real-time, multiprogramming, multiprocessor operating system, and the possible use of advanced development techniques such as expert systems and artificial intelligence tools in the DMS design.

  17. Developing Scalable Information Security Systems

    Directory of Open Access Journals (Sweden)

    Valery Konstantinovich Ablekov

    2013-06-01

    Full Text Available Existing physical security systems has wide range of lacks, including: high cost, a large number of vulnerabilities, problems of modification and support system. This paper covers an actual problem of developing systems without this list of drawbacks. The paper presents the architecture of the information security system, which operates through the network protocol TCP/IP, including the ability to connect different types of devices and integration with existing security systems. The main advantage is a significant increase in system reliability, scalability, both vertically and horizontally, with minimal cost of both financial and time resources.

  18. Business system: Sustainable development and anticipatory system

    Directory of Open Access Journals (Sweden)

    Vojko Potočan

    2002-01-01

    Full Text Available The existence and development of humankind depends mainly upon the co-ordinated operation of all areas and levels of human activity. However, in theory and in practice there is no model of operation, which would provide a harmonized and target oriented development. A partial solution is offered by sustainable development, which tries to define and carry out common goals of mankind with a harmonized implementation of human activities at all levels of its living and behaviour. Companies belong to central institutions of modern society which essentially co–create the sustainability of society. The company’s endeavour by simulation to prepare models of their goals concerning their internal and external environment. On the base of systemic treatment, we can define companies as business system, which can survive in a log-run only on the basis of sustainable development. The business system can also be supported by the application of the anticipatory systems. The anticipatory systems can be, in this sense, understood as an entity of the methodological approach, techniques and modes of work. Their characteristics have, a direct impact on the determination of goals, on the orientation of operation, and hence on the achievement of the business system results.

  19. Development of RF non-IQ sampling module for Helium RFQ LLRF system

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hae-Seong; Ahn, Tae-Sung; Kim, Seong-Gu; Kwon, Hyeok-Jung; Kim, Han-Sung; Song, Young-Gi; Seol, Kyung-Tae; Cho, Yong-Sub [KOMAC, Gyeongju (Korea, Republic of)

    2015-05-15

    KOMAC (Korea Multi-purpose Accelerator Complex) has a plan to develop the helium irradiation system. This system includes the Ion source, LEBT, RFQ, MEBT systems to transport helium particles to the target. Especially, the RFQ (Radio Frequency Quadrupole) system should receive the 200MHz RF within 1% amplitude error stability. For supplying stable 200MHz RF to the RFQ, the low-level radio frequency (LLRF) should be controlled by control system. The helium RFQ LLRF control system adopted non- IQ sampling method to sample the analog input RF. Sampled input data will be calculated to get the I, Q values. These I, Q values will be used to monitor the amplitude and phase of the RF signal. In this paper, non-IQ sampling logic and amplitude and phase calculating logic of the FPGA will be introduced. Using Xilinx ISE design suite which is tool for developing the FPGA logic module, non-IQ sampling module and amplitude and phase computing module developed. In the future, PI gain module and frequency error computing module will be developed.

  20. Dynamics of the diluted Ising antiferromagnet Fe0.42Zn0.58F2 at strong fields

    International Nuclear Information System (INIS)

    Rosales-Rivera, A.; Ferreira, J.M.; Montenegro, F.C.

    2001-01-01

    The random-field Ising model (RFIM) system Fe 0.42 Zn 0.58 F 2 is studied by magnetization and AC susceptibility measurements, under finite DC applied fields (H). For weak random fields (corresponding to H c (H) is accompanied by the critical slowing down inherent to the random field problem. For higher H, the PT is destroyed and a glassy dynamics dominates the magnetic behavior

  1. Devil's flower resulting from a successive charge disproportionation of NaV2O5. Understanding of the details of the Ising spin and the competitive interactions which made the devil's flower bloom

    International Nuclear Information System (INIS)

    Ohwada, Kenji; Fujii, Yasuhiko; Shobu, Takahisa; Muraoka, Jiro

    2008-01-01

    Devil's flower has been found in a temperature-pressure phase diagram of NaV 2 O 5 , which shows a charge disproportionation (CD) at ambient pressure. By a complementary use of an x-ray structural analysis and a resonant x-ray diffraction, which is sensitive to CD, we have investigated the structural relationship between two ground states appeared in lower and higher pressure regions including the charge arrangements. It has been clarified that two equivalent types of charge arrangement in CD correspond to the Ising variable in NaV 2 O 5 . The atomic shifts are regarded as linearly coupled to the Ising spins. The results lead us to the conclusion that the devil's flower blooms in a charge-disproportionation system. The results also lead us to a hypothesis that the competitive interactions between Ising spins may result from the Ising spin-phonon coupling. (author)

  2. Free energy distribution function of a random Ising ferromagnet

    International Nuclear Information System (INIS)

    Dotsenko, Victor; Klumov, Boris

    2012-01-01

    We study the free energy distribution function of a weakly disordered Ising ferromagnet in terms of the D-dimensional random temperature Ginzburg–Landau Hamiltonian. It is shown that besides the usual Gaussian 'body' this distribution function exhibits non-Gaussian tails both in the paramagnetic and in the ferromagnetic phases. Explicit asymptotic expressions for these tails are derived. It is demonstrated that the tails are strongly asymmetric: the left tail (for large negative values of the free energy) is much slower than the right one (for large positive values of the free energy). It is argued that at the critical point the free energy of the random Ising ferromagnet in dimensions D < 4 is described by a non-trivial universal distribution function which is non-self-averaging

  3. Ecological risk assessment of TBT in Ise Bay.

    Science.gov (United States)

    Yamamoto, Joji; Yonezawa, Yoshitaka; Nakata, Kisaburo; Horiguchi, Fumio

    2009-02-01

    An ecological risk assessment of tributyltin (TBT) in Ise Bay was conducted using the margin of exposure (MOE) method. The assessment endpoint was defined to protect the survival, growth and reproduction of marine organisms. Sources of TBT in this study were assumed to be commercial vessels in harbors and navigation routes. Concentrations of TBT in Ise Bay were estimated using a three-dimensional hydrodynamic model, an ecosystem model and a chemical fate model. Estimated MOEs for marine organisms for 1990 and 2008 were approximately 0.1-2.0 and over 100 respectively, indicating a declining temporal trend in the probability of adverse effects. The chemical fate model predicts a much longer persistence of TBT in sediments than in the water column. Therefore, it is necessary to monitor the harmful effects of TBT on benthic organisms.

  4. OpenCL Implementation of NeuroIsing

    Science.gov (United States)

    Zapart, C. A.

    Recent advances in graphics card hardware combined with anintroduction of the OpenCL standard promise to accelerate numerical simulations across diverse scientific disciplines. One such field benefiting from new hardware/software paradigms is econophysics. The paper describes an OpenCL implementation of a selected econophysics model: NeuroIsing, which has been designed to execute in parallel on a vendor-independent graphics card. Originally introduced in the paper [C.~A.~Zapart, ``Econophysics in Financial Time Series Prediction'', PhD thesis, Graduate University for Advanced Studies, Japan (2009)], at first it was implemented on a CELL processor running inside a SONY PS3 games console. The NeuroIsing framework can be applied to predicting and trading foreign exchange as well as stock market index futures.

  5. Dynamical quantum phase transitions in extended transverse Ising models

    Science.gov (United States)

    Bhattacharjee, Sourav; Dutta, Amit

    2018-04-01

    We study the dynamical quantum phase transitions (DQPTs) manifested in the subsequent unitary dynamics of an extended Ising model with an additional three spin interactions following a sudden quench. Revisiting the equilibrium phase diagram of the model, where different quantum phases are characterized by different winding numbers, we show that in some situations the winding number may not change across a gap closing point in the energy spectrum. Although, usually there exists a one-to-one correspondence between the change in winding number and the number of critical time scales associated with DQPTs, we show that the extended nature of interactions may lead to unusual situations. Importantly, we show that in the limit of the cluster Ising model, three critical modes associated with DQPTs become degenerate, thereby leading to a single critical time scale for a given sector of Fisher zeros.

  6. Ising model on tangled chain - 1: Free energy and entropy

    International Nuclear Information System (INIS)

    Mejdani, R.

    1993-04-01

    In this paper we have considered an Ising model defined on tangled chain, in which more bonds have been added to those of pure Ising chain. to understand their competition, particularly between ferromagnetic and antiferromagnetic bonds, we have studied, using the transfer matrix method, some simple analytical calculations and an iterative algorithm, the behaviour of the free energy and entropy, particularly in the zero-field and zero temperature limit, for different configurations of the ferromagnetic tangled chain and different types of addition interaction (ferromagnetic or antiferromagnetic). We found that the condition J=J' between the ferromagnetic interaction J along the chain and the antiferromagnetic interaction J' across the chain is somewhat as a ''transition-region'' condition for this behaviour. Our results indicate also the existence of non-zero entropy at zero temperature. (author). 17 refs, 8 figs

  7. Precision islands in the Ising and O(N) models

    Energy Technology Data Exchange (ETDEWEB)

    Kos, Filip [Department of Physics, Yale University, New Haven, CT 06520 (United States); Poland, David [Department of Physics, Yale University, New Haven, CT 06520 (United States); School of Natural Sciences, Institute for Advanced Study, Princeton, New Jersey 08540 (United States); Simmons-Duffin, David [School of Natural Sciences, Institute for Advanced Study, Princeton, New Jersey 08540 (United States); Vichi, Alessandro [Theory Division, CERN, Geneva (Switzerland)

    2016-08-04

    We make precise determinations of the leading scaling dimensions and operator product expansion (OPE) coefficients in the 3d Ising, O(2), and O(3) models from the conformal bootstrap with mixed correlators. We improve on previous studies by scanning over possible relative values of the leading OPE coefficients, which incorporates the physical information that there is only a single operator at a given scaling dimension. The scaling dimensions and OPE coefficients obtained for the 3d Ising model, (Δ{sub σ},Δ{sub ϵ},λ{sub σσϵ},λ{sub ϵϵϵ})=(0.5181489(10),1.412625(10),1.0518537(41),1.532435(19)), give the most precise determinations of these quantities to date.

  8. Precision Islands in the Ising and $O(N)$ Models

    CERN Document Server

    Kos, Filip; Simmons-Duffin, David; Vichi, Alessandro

    2016-01-01

    We make precise determinations of the leading scaling dimensions and operator product expansion (OPE) coefficients in the 3d Ising, $O(2)$, and $O(3)$ models from the conformal bootstrap with mixed correlators. We improve on previous studies by scanning over possible relative values of the leading OPE coefficients, which incorporates the physical information that there is only a single operator at a given scaling dimension. The scaling dimensions and OPE coefficients obtained for the 3d Ising model, $(\\Delta_{\\sigma}, \\Delta_{\\epsilon},\\lambda_{\\sigma\\sigma\\epsilon}, \\lambda_{\\epsilon\\epsilon\\epsilon}) = (0.5181489(10), 1.412625(10), 1.0518537(41), 1.532435(19))$, give the most precise determinations of these quantities to date.

  9. Ising Processing Units: Potential and Challenges for Discrete Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Coffrin, Carleton James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nagarajan, Harsha [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bent, Russell Whitford [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-07-05

    The recent emergence of novel computational devices, such as adiabatic quantum computers, CMOS annealers, and optical parametric oscillators, presents new opportunities for hybrid-optimization algorithms that leverage these kinds of specialized hardware. In this work, we propose the idea of an Ising processing unit as a computational abstraction for these emerging tools. Challenges involved in using and bench- marking these devices are presented, and open-source software tools are proposed to address some of these challenges. The proposed benchmarking tools and methodology are demonstrated by conducting a baseline study of established solution methods to a D-Wave 2X adiabatic quantum computer, one example of a commercially available Ising processing unit.

  10. Genus-two characters of the Ising model

    International Nuclear Information System (INIS)

    Choi, J.H.; Koh, I.G.

    1989-01-01

    As a first step in studying conformal theories on a higher-genus Riemann surface, we construct genus-two characters of the Ising model from their behavior in zero- and nonzero-homology pinching limits, the Goddard-Kent-Oliveco set-space construction, and the branching coefficients in the level-two A 1 /sup (1)/ Kac-Moody characters on the higher-genus Riemann surface

  11. Conditional CAPM and an Application on the ISE

    OpenAIRE

    Yalcin Karatepe; Elif Karaaslan; Fazil Gokgoz

    2002-01-01

    In the empirical studies carried out on standard CAPM, widely used in finance literature, it has been argued that static CAPM could not entirely explain the portfolio returns. One of the assumptions for one period application is that the beta coefficients of assets are assumed to be constant over time. However, in a dynamic world the expected returns and betas deviate over time. In this study, returns of ISE-30 securities have been estimated by employing conditional CAPM; it has been found th...

  12. Investigating Investment Preferences of Institutional Investors toward ISE Companies

    OpenAIRE

    Serkan Yilmaz Kandir

    2010-01-01

    Institutional investors may be defined as specialized financial institutions that manage savings collectively on behalf of small investors toward specific objectives. Aim of this study is to investigate the factors that affect investment preferences of institutional investors toward ISE companies. Empirical analysis is performed by employing cross-sectional regression model. In the regression model, estimated for the years, 2005, 2006 and 2007, institutional ownership in each company is used ...

  13. Performance evaluation of coherent Ising machines against classical neural networks

    Science.gov (United States)

    Haribara, Yoshitaka; Ishikawa, Hitoshi; Utsunomiya, Shoko; Aihara, Kazuyuki; Yamamoto, Yoshihisa

    2017-12-01

    The coherent Ising machine is expected to find a near-optimal solution in various combinatorial optimization problems, which has been experimentally confirmed with optical parametric oscillators and a field programmable gate array circuit. The similar mathematical models were proposed three decades ago by Hopfield et al in the context of classical neural networks. In this article, we compare the computational performance of both models.

  14. Phase transitions of a spin-one Ising ferromagnetic superlattice

    International Nuclear Information System (INIS)

    Saber, A.

    2001-09-01

    Using the effective field theory with a probability distribution technique, the magnetic properties in an infinite superlattice consisting of two different ferromagnets are studied in a spin-one Ising model. The dependence of the Curie temperatures are calculated as a function of two slabs in one period and as a function of the intra- and interlayer exchange interactions. A critical value of the exchange reduced interaction above which the interface magnetism appears is found. (author)

  15. Phase transitions of ferromagnetic Ising films with amorphous surfaces

    International Nuclear Information System (INIS)

    Saber, M.; Ainane, A.; Dujardin, F.; Stebe, B.

    1997-08-01

    The critical behavior of a ferromagnetic Ising film with amorphous surfaces is studied within the framework of the effective field theory. The dependence of the critical temperature on exchange interaction strength ratio, film thickness, and structural fluctuation parameter is presented. It is found that an order-disorder magnetic transition occurs by varying the thickness of the film. Such a result is in agreement with experiments performed recently on Fe-films. (author). 39 refs, 4 figs

  16. Out-of-time-ordered correlators in a quantum Ising chain

    Science.gov (United States)

    Lin, Cheng-Ju; Motrunich, Olexei I.

    2018-04-01

    Out-of-time-ordered correlators (OTOC) have been proposed to characterize quantum chaos in generic systems. However, they can also show interesting behavior in integrable models, resembling the OTOC in chaotic systems in some aspects. Here we study the OTOC for different operators in the exactly-solvable one-dimensional quantum Ising spin chain. The OTOC for spin operators that are local in terms of the Jordan-Wigner fermions has a "shell-like" structure: After the wavefront passes, the OTOC approaches its original value in the long-time limit, showing no signature of scrambling; the approach is described by a t-1 power law at long time t . On the other hand, the OTOC for spin operators that are nonlocal in the Jordan-Wigner fermions has a "ball-like" structure, with its value reaching zero in the long-time limit, looking like a signature of scrambling; the approach to zero, however, is described by a slow power law t-1 /4 for the Ising model at the critical coupling. These long-time power-law behaviors in the lattice model are not captured by conformal field theory calculations. The mixed OTOC with both local and nonlocal operators in the Jordan-Wigner fermions also has a "ball-like" structure, but the limiting values and the decay behavior appear to be nonuniversal. In all cases, we are not able to define a parametrically large window around the wavefront to extract the Lyapunov exponent.

  17. Search for the non-canonical Ising spin glass on rewired square lattices

    Science.gov (United States)

    Surungan, Tasrief

    2018-03-01

    A spin glass (SG) of non-canonical type is a purely antiferromagnetic (AF) system, exemplified by the AF Ising model on a scale free network (SFN), studied by Bartolozzi et al. [ Phys. Rev. B73, 224419 (2006)]. Frustration in this new type of SG is rendered by topological factor and its randomness is caused by random connectivity. As an SFN corresponds to a large dimensional lattice, finding non-canonical SG in lattice with physical dimension is desireable. However, a regular lattice can not have random connectivity. In order to obtain lattices with random connection and preserving the notion of finite dimension, we costructed rewired lattices. We added some extra bonds randomly connecting each site of a regular lattice to its next-nearest neighbors. Very recently, Surungan et al., studied AF Heisenberg system on rewired square lattice and found no SG behavior [AIP Conf. Proc. 1719, 030006 (2016)]. Due to the importance of discrete symmetry for phase transition, here we study similar structure for the Ising model (Z 2 symmetry). We used Monte Carlo simulation with Replica Exchange algorithm. Two types of structures were studied, firstly, the rewired square lattices with one extra bonds added to each site, and secondly, two bonds added to each site. We calculated the Edwards-Anderson paremeter, the commonly used parameter in searching for SG phase. The non-canonical SG is clearly observed in the rewired square lattice with two extra bonds added.

  18. Development of Cubesat Propulsion Systems

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall objective of this IRAD will be to develop a propulsion system that can be cheaply and reliably used for NASA GSFC cubesat missions. Reliability will be...

  19. Radioisotope Power Systems Technology Development

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of the RPS's technology portfolio is to advance performance of radioisotope power systems through new and novel innovations being developed and transitioned...

  20. Information system development activities and inquiring systems

    DEFF Research Database (Denmark)

    Carugati, Andrea

    2008-01-01

    This article presents a framework that maps information system development (ISD) activities on systems for the creation of knowledge. This work addresses the relevant and persisting problem of improving the chances of ISD success. The article builds upon previous research on knowledge aspects...... based on ISD literature and on Churchman's (1971) inquiring systems. The second part presents the use of the framework in an ISD project. The case is used to show the applicability of the framework and to highlight the advantages of this approach. The main theoretical implication is that the framework...

  1. ISEE/IMP Observations of simultaneous upstream ion events

    International Nuclear Information System (INIS)

    Mitchel, D.G.; Roelof, E.C.; Sanderson, T.R.; Reinhard, R.; Wenzel, K.

    1983-01-01

    Propagation of upstream energetic (50--200 keV) ions is analyzed in sixteen events observed simulataneously by solid state detectors on ISEE 3 at approx.200 R/sub E/ and on IMP 8 at approx.35 R/sub E/ from the earth. Conclusions are based on comparisons of the pitch angle distributions observed at the two spacecraft and transformed into the solar wind frame. They are beamlike at ISEE 3 and are confined to the outward hemisphere. When IMP 8 is furtherest from the bow shock, they are also usually beamlike, or hemispheric. However, when IMP 8 is closer to the bow shock, pancakelike distributions are observed. This systematic variation in the IMP 8 pitch angle distributions delimits a scattering region l< or approx. =14 R/sub E/ upstream of the earth's bow shock (l measured along the interplanetary magnetic field) that dominates ion propagation, influences the global distribution of fluxes in the foreshock, and may play a role in acceleration of the ions. When IMP 8 is beyond lapprox.15 R/sub E/, the propagation appears to be essentially scatter-free between IMP 8 and ISEE 3; this is deduced from the absence of earthward fluxes at IMP 8 as well as the tendency for the spin-averaged fluxes to be comparable at the two spacecraft

  2. Dynamic phase diagrams of a cylindrical Ising nanowire in the presence of a time dependent magnetic field

    International Nuclear Information System (INIS)

    Kantar, Ersin; Ertaş, Mehmet; Keskin, Mustafa

    2014-01-01

    The dynamic phase diagrams of a cylindrical Ising nanowire in the presence of a time dependent magnetic field are obtained by using the effective-field theory with correlations based on the Glauber-type stochastic dynamics. According to the values of interaction parameters, a number of interesting properties have been found in the dynamic phase diagrams, such as many dynamic critical points (tricritical point, double critical end point, critical end point, zero temperature critical point, multicritical point, tetracritical point, and triple point) as well as reentrant phenomena. - Highlights: • The cylindrical Ising nanowire is investigated within the Glauber dynamics based on EFT. • The time variations of average order parameters to find phases are studied. • The dynamic phase diagrams are found for the different interaction parameters. • The system displays the critical points as well as a reentrant behavior

  3. Dynamic phase diagrams of a cylindrical Ising nanowire in the presence of a time dependent magnetic field

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-01

    The dynamic phase diagrams of a cylindrical Ising nanowire in the presence of a time dependent magnetic field are obtained by using the effective-field theory with correlations based on the Glauber-type stochastic dynamics. According to the values of interaction parameters, a number of interesting properties have been found in the dynamic phase diagrams, such as many dynamic critical points (tricritical point, double critical end point, critical end point, zero temperature critical point, multicritical point, tetracritical point, and triple point) as well as reentrant phenomena. - Highlights: • The cylindrical Ising nanowire is investigated within the Glauber dynamics based on EFT. • The time variations of average order parameters to find phases are studied. • The dynamic phase diagrams are found for the different interaction parameters. • The system displays the critical points as well as a reentrant behavior.

  4. Effects of the randomly distributed magnetic field on the phase diagrams of the Ising Nanowire II: Continuous distributions

    International Nuclear Information System (INIS)

    Akıncı, Ümit

    2012-01-01

    The effect of the random magnetic field distribution on the phase diagrams and ground state magnetizations of the Ising nanowire has been investigated with effective field theory with correlations. Gaussian distribution has been chosen as a random magnetic field distribution. The variation of the phase diagrams with that distribution parameters has been obtained and some interesting results have been found such as disappearance of the reentrant behavior and first order transitions which appear in the case of discrete distributions. Also for single and double Gaussian distributions, ground state magnetizations for different distribution parameters have been determined which can be regarded as separate partially ordered phases of the system. - Highlights: ► We give the phase diagrams of the Ising nanowire under the continuous randomly distributed magnetic field. ► Ground state magnetization values obtained. ► Different partially ordered phases observed.

  5. TADS: Technical Assistance Development System.

    Science.gov (United States)

    Epting, Rosemary, Ed.

    Described is the Technical Assistance Development System (TADS), a component of the Frank Porter Graham Child Development Center of the University of North Carolina at Chapel Hill which offers support services to preschool demonstration centers for handicapped children in the First Chance Network. Discussed are the four types of services offered:…

  6. Development of the auditory system

    Science.gov (United States)

    Litovsky, Ruth

    2015-01-01

    Auditory development involves changes in the peripheral and central nervous system along the auditory pathways, and these occur naturally, and in response to stimulation. Human development occurs along a trajectory that can last decades, and is studied using behavioral psychophysics, as well as physiologic measurements with neural imaging. The auditory system constructs a perceptual space that takes information from objects and groups, segregates sounds, and provides meaning and access to communication tools such as language. Auditory signals are processed in a series of analysis stages, from peripheral to central. Coding of information has been studied for features of sound, including frequency, intensity, loudness, and location, in quiet and in the presence of maskers. In the latter case, the ability of the auditory system to perform an analysis of the scene becomes highly relevant. While some basic abilities are well developed at birth, there is a clear prolonged maturation of auditory development well into the teenage years. Maturation involves auditory pathways. However, non-auditory changes (attention, memory, cognition) play an important role in auditory development. The ability of the auditory system to adapt in response to novel stimuli is a key feature of development throughout the nervous system, known as neural plasticity. PMID:25726262

  7. Network of time-multiplexed optical parametric oscillators as a coherent Ising machine

    Science.gov (United States)

    Marandi, Alireza; Wang, Zhe; Takata, Kenta; Byer, Robert L.; Yamamoto, Yoshihisa

    2014-12-01

    Finding the ground states of the Ising Hamiltonian maps to various combinatorial optimization problems in biology, medicine, wireless communications, artificial intelligence and social network. So far, no efficient classical and quantum algorithm is known for these problems and intensive research is focused on creating physical systems—Ising machines—capable of finding the absolute or approximate ground states of the Ising Hamiltonian. Here, we report an Ising machine using a network of degenerate optical parametric oscillators (OPOs). Spins are represented with above-threshold binary phases of the OPOs and the Ising couplings are realized by mutual injections. The network is implemented in a single OPO ring cavity with multiple trains of femtosecond pulses and configurable mutual couplings, and operates at room temperature. We programmed a small non-deterministic polynomial time-hard problem on a 4-OPO Ising machine and in 1,000 runs no computational error was detected.

  8. Development of the accelerating system

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jiho; Kwon, H. J.; Kim, D. I.; Kim, H. S.; Ryu, J. Y.; Park, B. S.; Seol, K. T.; Yun, S. P.; Song, Y. G.; Cho, Y. S.

    2013-02-15

    One of the main purposes of the 'Development of the Accelerating System' is developing a 100-MeV proton linac which accelerate proton beams from 20 MeV to 100 MeV by using 7 DTL (drift tube linac) tanks. Two of them were finished in the 2-nd stage of the project. The remaining part was also successfully fabricated and installed at Gyeongju site of KAERI. The MEBT is an essential component to extract and supply 20-MeV proton beams to users, and to match proton beams to the next accelerating structure for 100-MeV acceleration. The development of the MEBT has successfully finished. The project also developed the digital LLRF (low level RF) system which control the accelerating field within 1% in magnitude and 1 degree in phase. This system has been successfully tested in the 20-MeV linac operation at Daejeon site of KAERI. The modified version of the digital LLRF system will be used in the 100-MeV linac operation. The project also developed the beam diagnostic system. They are the strip-line type beam position monitor (BPM), the beam current monitor (CT), the beam loss monitor (BLM), and the emittance measurement system. They are used to measure the characteristics of the 20-MeV proton beams. The project also developed the EPIC-based control system. It is used to monitor the status of the accelerator and components, and to remotely control accelerator components. It has been used and modified in the 20-MeV linac operation. The modified version of the LLRF, diagnostics and control systems will be used in 100-MeV linac operation.

  9. Development of refueling support system

    International Nuclear Information System (INIS)

    Nishimura, Hiroshi; Hayashi, Shoichi; Sano, Kazuya; Hochin, Koji; Iguchi, Yukihiro

    1992-01-01

    The refueling of Fugen Nuclear Power Station requires correct management of fuels, etc. And empirical knowledge is necessary for efficient planning and refueling. Fugen developed refueling support system and put it into practical operation. The system features a network of refueling equipment and AI rules aquired from operators knowledge. The system helps make an optimized plan, displays step-by-step guidance and prints out lists of fuel locations and movements. The system reduced the labor of the operators, optimized the management and improved the reliability of the refueling. (author)

  10. Monte Carlo Studies of Phase Separation in Compressible 2-dim Ising Models

    Science.gov (United States)

    Mitchell, S. J.; Landau, D. P.

    2006-03-01

    Using high resolution Monte Carlo simulations, we study time-dependent domain growth in compressible 2-dim ferromagnetic (s=1/2) Ising models with continuous spin positions and spin-exchange moves [1]. Spins interact with slightly modified Lennard-Jones potentials, and we consider a model with no lattice mismatch and one with 4% mismatch. For comparison, we repeat calculations for the rigid Ising model [2]. For all models, large systems (512^2) and long times (10^ 6 MCS) are examined over multiple runs, and the growth exponent is measured in the asymptotic scaling regime. For the rigid model and the compressible model with no lattice mismatch, the growth exponent is consistent with the theoretically expected value of 1/3 [1] for Model B type growth. However, we find that non-zero lattice mismatch has a significant and unexpected effect on the growth behavior.Supported by the NSF.[1] D.P. Landau and K. Binder, A Guide to Monte Carlo Simulations in Statistical Physics, second ed. (Cambridge University Press, New York, 2005).[2] J. Amar, F. Sullivan, and R.D. Mountain, Phys. Rev. B 37, 196 (1988).

  11. GPU-Accelerated Population Annealing Algorithm: Frustrated Ising Antiferromagnet on the Stacked Triangular Lattice

    Directory of Open Access Journals (Sweden)

    Borovský Michal

    2016-01-01

    Full Text Available The population annealing algorithm is a novel approach to study systems with rough free-energy landscapes, such as spin glasses. It combines the power of simulated annealing, Boltzmann weighted differential reproduction and sequential Monte Carlo process to bring the population of replicas to the equilibrium even in the low-temperature region. Moreover, it provides a very good estimate of the free energy. The fact that population annealing algorithm is performed over a large number of replicas with many spin updates, makes it a good candidate for massive parallelism. We chose the GPU programming using a CUDA implementation to create a highly optimized simulation. It has been previously shown for the frustrated Ising antiferromagnet on the stacked triangular lattice with a ferromagnetic interlayer coupling, that standard Markov Chain Monte Carlo simulations fail to equilibrate at low temperatures due to the effect of kinetic freezing of the ferromagnetically ordered chains. We applied the population annealing to study the case with the isotropic intra- and interlayer antiferromagnetic coupling (J2/|J1| = −1. The reached ground states correspond to non-magnetic degenerate states, where chains are antiferromagnetically ordered, but there is no long-range ordering between them, which is analogical with Wannier phase of the 2D triangular Ising antiferromagnet.

  12. Instrument for Solvent Extraction and Analysis (ISEE) of Organics from Regolith Simulant Using Supercritical Fluid Extraction and Chromatography

    Science.gov (United States)

    Franco, Carolina; Hintze, Paul E.

    2017-01-01

    ISEE is an instrument with the potential to perform extractions from regolith found on the surface of asteroids and planets, followed by characterization and quantitation of the extracts using supercritical fluid extraction (SFE) and chromatography (SFC). SFE is a developed technique proven to extract a wide range of organic compounds. SFC is similar to High Performance Liquid Chromatography (HPLC) but has the advantage of performing chiral separations without needing to derivatize the chiral compounds. CO2 will be the solvent for both stages as it is readily available in the Mars atmosphere. ISEE will capture CO2 from the environment, and use it for SFE and SFC. If successful, this would allow ISEE to perform analysis of organic compounds without using consumables. This paper will present results on a preliminary, proof-of-principle effort to use SFE and SFC to extract and analyze lunar regolith simulant spiked with organic compounds representing a range of organics that ISEE would expect to characterize. An optimization of variables for the extraction of the organics from the spiked regolith was successfully developed, using 138 bar pressure and 40 C temperature. The extraction flow rate was optimized at 2% SLPM with 30% methanol modifier. The extractions were successful with a value of 77.3+/- 0.9% of organics extracted. However, the recovery of organics after the extraction was very low with only 48.5+/-14.2%. Moreover, three columns were selected to analyze multiple samples at a time; two of them are Viridis HSS C18 SB and Torus DIOL, and the third column, specific for chiral separations, has not yet been selected yet.

  13. The Ising model for prediction of disordered residues from protein sequence alone

    International Nuclear Information System (INIS)

    Lobanov, Michail Yu; Galzitskaya, Oxana V

    2011-01-01

    Intrinsically disordered regions serve as molecular recognition elements, which play an important role in the control of many cellular processes and signaling pathways. It is useful to be able to predict positions of disordered residues and disordered regions in protein chains using protein sequence alone. A new method (IsUnstruct) based on the Ising model for prediction of disordered residues from protein sequence alone has been developed. According to this model, each residue can be in one of two states: ordered or disordered. The model is an approximation of the Ising model in which the interaction term between neighbors has been replaced by a penalty for changing between states (the energy of border). The IsUnstruct has been compared with other available methods and found to perform well. The method correctly finds 77% of disordered residues as well as 87% of ordered residues in the CASP8 database, and 72% of disordered residues as well as 85% of ordered residues in the DisProt database

  14. A unified effective-field renormalization-group framework approach for the quenched diluted Ising models

    Science.gov (United States)

    de Albuquerque, Douglas F.; Fittipaldi, I. P.

    1994-05-01

    A unified effective-field renormalization-group framework (EFRG) for both quenched bond- and site-diluted Ising models is herein developed by extending recent works. The method, as in the previous works, follows up the same strategy of the mean-field renormalization-group scheme (MFRG), and is achieved by introducing an alternative way for constructing classical effective-field equations of state, based on rigorous Ising spin identities. The concentration dependence of the critical temperature, Tc(p), and the critical concentrations of magnetic atoms, pc, at which the transition temperature goes to zero, are evaluated for several two- and three-dimensional lattice structures. The obtained values of Tc and pc and the resulting phase diagrams for both bond and site cases are much more accurate than those estimated by the standard MFRG approach. Although preserving the same level of simplicity as the MFRG, it is shown that the present EFRG method, even by considering its simplest size-cluster version, provides results that correctly distinguishes those lattices that have the same coordination number, but differ in dimensionality or geometry.

  15. Development of plant maintenance systems

    International Nuclear Information System (INIS)

    Tomita, Jinji; Ike, Masae; Nakayama, Kenji; Kato, Hisatomo

    1989-01-01

    Toshiba is making active efforts for the continuing improvement of reliability and maintainability of operating nuclear power plants. As a part of these efforts, the company has developed new maintenance administration systems, diagnostic monitoring facilities for plant equipments, computer-aided expert systems, and remote-controlled machines for maintenance work. The maintenance administration systems provide efficient work plans and data acquisition capabilities for the management of personnel and equipments involved in nuclear power plant maintenance. The plant diagnostic facilities monitor and diagnose plant conditions for preventive maintenance, as well as enabling rapid countermeasures to be carried out should they be required. Expert systems utilizing artificial intelligence (AI) technology are also employed. The newly developed remote-controlled machines are useful tools for the maintenance inspection of equipment which can not be easily accessed. (author)

  16. Mixed spin Ising model with four-spin interaction and random crystal field

    International Nuclear Information System (INIS)

    Benayad, N.; Ghliyem, M.

    2012-01-01

    The effects of fluctuations of the crystal field on the phase diagram of the mixed spin-1/2 and spin-1 Ising model with four-spin interactions are investigated within the finite cluster approximation based on a single-site cluster theory. The state equations are derived for the two-dimensional square lattice. It has been found that the system exhibits a variety of interesting features resulting from the fluctuation of the crystal field interactions. In particular, for low mean value D of the crystal field, the critical temperature is not very sensitive to fluctuations and all transitions are of second order for any value of the four-spin interactions. But for relatively high D, the transition temperature depends on the fluctuation of the crystal field, and the system undergoes tricritical behaviour for any strength of the four-spin interactions. We have also found that the model may exhibit reentrance for appropriate values of the system parameters.

  17. Electronic transport on the Shastry-Sutherland lattice in Ising-type rare-earth tetraborides

    Science.gov (United States)

    Ye, Linda; Suzuki, Takehito; Checkelsky, Joseph G.

    2017-05-01

    In the presence of a magnetic field frustrated spin systems may exhibit plateaus at fractional values of saturation magnetization. Such plateau states are stabilized by classical and quantum mechanisms including order by disorder, triplon crystallization, and various competing order effects. In the case of electrically conducting systems, free electrons represent an incisive probe for the plateau states. Here we study the electrical transport of Ising-type rare-earth tetraborides R B4 (R =Er , Tm), a metallic Shastry-Sutherland lattice showing magnetization plateaus. We find that the longitudinal and transverse resistivities reflect scattering with both the static and the dynamic plateau structure. We model these results consistently with the expected strong uniaxial anisotropy on a quantitative level, providing a framework for the study of plateau states in metallic frustrated systems.

  18. Electrical Transport on the Shastry-Sutherland Lattice in Ising-type Rare Earth Tetraborides

    Science.gov (United States)

    Ye, Linda; Suzuki, Takehito; Checkelsky, Joseph. G.

    In the presence of a magnetic field, frustrated spin systems may exhibit plateaus at fractional values of their saturation magnetization. Study of the magnetic ordering and excitations at such plateaus are key to understanding the nature of the underlying ground states in these systems. Here we study the magnetization plateaus in metallic rare earth tetraborides RB4 with Ising-type anisotropy (R = Er, Tm) in which R resides on a Shastry-Sutherland lattice. We focus on electrical transport and find that the response reflects scattering of charge carriers with the static and dynamic plateau structure. Modeling of these results is consistent with the expected strong uniaxial anisotropy and provides a framework for the study of plateau states in metallic frustrated systems. We thank NSF Grant No. DMR-1231319, Tsinghua Education Foundation, Moore foundation Grant No. GBMF3848 for support.

  19. Development of maintenance engineering system

    International Nuclear Information System (INIS)

    1995-03-01

    Department of JMTR project has developed the Maintenance Engineering System which evaluates the aging tendency of the facilities. The system is used for the repair plan and the replace period of parts, components, equipments or facilities. The system has the data-base which consists of the check data, the inspection data, the trouble data and the repair data at the JMTR since the virgin criticality. The system is utilized maintenance works and concludes the maintenance procedures for the failure components, equipments and facilities. This system has the following characteristics. (1) Anybody can operate the system as easily as word processor. (2) Data are put into by man-machine-interface. (3) The data sheets are with light color and the recognizable arrangements. (4) The system is cost-efficient using commercial personal computers and applications. The research card and the layouts of the input data sheet had been formatted. Data has been begun to be put into the system and to check its functions. The result demonstrates that the system is available for preventive maintenance at the JMTR. (author)

  20. DEVELOPMENT OF MANAGEMENT INFORMATION SYSTEMS

    OpenAIRE

    Wiesław Samitowski

    2016-01-01

    On the basis of many years of experience in providing consulting services in the area of management, the author presents the issues regarding the development of information systems to be applied in business. The analysis is conducted within the framework of a field of study introduced by the author and referred to as infornomics.

  1. Managing conflicts in systems development.

    Science.gov (United States)

    Barnett, E

    1997-05-01

    Conflict in systems development is nothing new. It can vary in intensity, but there will always be two possible outcomes--one constructive and the other destructive. The common approach to conflict management is to draw the battle lines and apply brute force. However, there are other ways to deal with conflict that are more effective and more people oriented.

  2. Model-based systems engineering to design collaborative robotics applications

    NARCIS (Netherlands)

    Hernandez Corbato, Carlos; Fernandez-Sanchez, Jose Luis; Rassa, Bob; Carbone, Paolo

    2017-01-01

    Novel robot technologies are becoming available to automate more complex tasks, more flexibly, and collaborating with humans. Methods and tools are needed in the automation and robotics industry to develop and integrate this new breed of robotic systems. In this paper, the ISE&PPOOA

  3. Recurrence relations in the three-dimensional Ising model

    International Nuclear Information System (INIS)

    Yukhnovskij, I.R.; Kozlovskij, M.P.

    1977-01-01

    Recurrence relations between the coefficients asub(2)sup((i)), asub(4)sup((i)) and Psub(2)sup((i)), Psub(4)sup((i)) which characterize the probabilities of distribution for the three-dimensional Ising model are studied. It is shown that for large arguments z of the Makdonald functions Ksub(ν)(z) the recurrence relations correspond to the known Wilson relations. But near the critical point for small values of the transfer momentum k this limit case does not take place. In the pointed region the argument z tends to zero, and new recurrence relations take place

  4. Magnetic properties of a single transverse Ising ferrimagnetic nanoparticle

    International Nuclear Information System (INIS)

    Bouhou, S.; El Hamri, M.; Essaoudi, I.; Ainane, A.; Ahuja, R.

    2015-01-01

    Using the effective field theory with a probability distribution technique that accounts for the self-spin correlation function, the thermal and the magnetic properties of a single Ising nanoparticle consisting of a ferromagnetic core, a ferromagnetic surface shell and a ferrimagnetic interface coupling are examined. The effect of the transverse field in the surface shell, the exchange interactions between core/shell and in surface shell on the free energy, thermal magnetization, specific heat and susceptibility are studied. A number of interesting phenomena have been found such as the existence of the compensation phenomenon and the magnetization profiles exhibit P-type, N-type and Q-type behaviors

  5. Logical operations realized on the Ising chain of N qubits

    International Nuclear Information System (INIS)

    Asano, Masanari; Tateda, Norihiro; Ishii, Chikara

    2004-01-01

    Multiqubit logical gates are proposed as implementations of logical operations on N qubits realized physically by the local manipulation of qubits before and after the one-time evolution of an Ising chain. This construction avoids complicated tuning of the interactions between qubits. The general rules of the action of multiqubit logical gates are derived by decomposing the process into the product of two-qubit logical operations. The formalism is demonstrated by the construction of a special type of multiqubit logical gate that is simulated by a quantum circuit composed of controlled-NOT gates

  6. Phase transition of the FCC Ising ferromagnet with competing interactions

    International Nuclear Information System (INIS)

    Oh, J.H.; Lee, J.Y.; Kim, D.C.

    1984-01-01

    A molecular field theory with correlation and Monte Carlo simulations are utilized to determine the zero field phase diagram of a fcc Ising model with ferromagnetic nearest neighbor(-J) and antiferromagnetic next neighbor (*aJ) interactions. The correlated molecular field theory predicts a fluctuation induced first order phase transition for 0.87<*a<1.31. Monte Carlo analysis indicates that the first order transition occurs for a somewhat wider range of *a. The transition temperatures obtained by the two methods are in good agreement especially near *a=1 where the fluctuation effect is expected to be large. (Author)

  7. Wind power: Italian auto-production legislation (ISES convention)

    International Nuclear Information System (INIS)

    Mari, G.

    1991-01-01

    With reference to what was discussed at the Bologna (Italy) June 1991 ISES (International Solar Energy Society) convention on wind energy, this paper summarizes the Italian legislative framework relative to on-site power generation and outlines the National Energy Plan objectives regarding the promotion of the use, by industry, of renewable energy sources. Brief notes are also provided on wind energy promotional activities being carried out by ENEL (the Italian National Energy Board), ENEA (Italian Agency for New Technologies, Energy and the Environment), and EWEA (the European Wind Energy Association)

  8. Ising model of financial markets with many assets

    Science.gov (United States)

    Eckrot, A.; Jurczyk, J.; Morgenstern, I.

    2016-11-01

    Many models of financial markets exist, but most of them simulate single asset markets. We study a multi asset Ising model of a financial market. Each agent has two possible actions (buy/sell) for every asset. The agents dynamically adjust their coupling coefficients according to past market returns and external news. This leads to fat tails and volatility clustering independent of the number of assets. We find that a separation of news into different channels leads to sector structures in the cross correlations, similar to those found in real markets.

  9. Markov chain analysis of single spin flip Ising simulations

    International Nuclear Information System (INIS)

    Hennecke, M.

    1997-01-01

    The Markov processes defined by random and loop-based schemes for single spin flip attempts in Monte Carlo simulations of the 2D Ising model are investigated, by explicitly constructing their transition matrices. Their analysis reveals that loops over all lattice sites using a Metropolis-type single spin flip probability often do not define ergodic Markov chains, and have distorted dynamical properties even if they are ergodic. The transition matrices also enable a comparison of the dynamics of random versus loop spin selection and Glauber versus Metropolis probabilities

  10. Decorated Ising models with competing interactions and modulated structures

    International Nuclear Information System (INIS)

    Tragtenberg, M.H.R.; Yokoi, C.S.O.; Salinas, S.R.A.

    1988-01-01

    The phase diagrams of a variety of decorated Ising lattices are calculated. The competing interactions among the decorating spins may induce different types of modulated orderings. In particular, the effect of an applied field on the phase diagram of the two-dimensional mock ANNNI model is considered, where only the original horizontal bonds on a square lattice are decorated. Some Bravais lattices and Cayley trees where all bonds are equally decorated are then studied. The Bravais lattices display a few stable modulated structures. The Cayley trees, on the other hand, display a large number of modulated phases, which increases with the lattice coordination number. (authors) [pt

  11. Entanglement dynamics in critical random quantum Ising chain with perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yichen, E-mail: ychuang@caltech.edu

    2017-05-15

    We simulate the entanglement dynamics in a critical random quantum Ising chain with generic perturbations using the time-evolving block decimation algorithm. Starting from a product state, we observe super-logarithmic growth of entanglement entropy with time. The numerical result is consistent with the analytical prediction of Vosk and Altman using a real-space renormalization group technique. - Highlights: • We study the dynamical quantum phase transition between many-body localized phases. • We simulate the dynamics of a very long random spin chain with matrix product states. • We observe numerically super-logarithmic growth of entanglement entropy with time.

  12. Probability distribution of magnetization in the one-dimensional Ising model: effects of boundary conditions

    Energy Technology Data Exchange (ETDEWEB)

    Antal, T [Physics Department, Simon Fraser University, Burnaby, BC V5A 1S6 (Canada); Droz, M [Departement de Physique Theorique, Universite de Geneve, CH 1211 Geneva 4 (Switzerland); Racz, Z [Institute for Theoretical Physics, Eoetvoes University, 1117 Budapest, Pazmany setany 1/a (Hungary)

    2004-02-06

    Finite-size scaling functions are investigated both for the mean-square magnetization fluctuations and for the probability distribution of the magnetization in the one-dimensional Ising model. The scaling functions are evaluated in the limit of the temperature going to zero (T {yields} 0), the size of the system going to infinity (N {yields} {infinity}) while N[1 - tanh(J/k{sub B}T)] is kept finite (J being the nearest neighbour coupling). Exact calculations using various boundary conditions (periodic, antiperiodic, free, block) demonstrate explicitly how the scaling functions depend on the boundary conditions. We also show that the block (small part of a large system) magnetization distribution results are identical to those obtained for free boundary conditions.

  13. Quantum dynamics in transverse-field Ising models from classical networks

    Directory of Open Access Journals (Sweden)

    Markus Schmitt, Markus Heyl

    2018-02-01

    Full Text Available The efficient representation of quantum many-body states with classical resources is a key challenge in quantum many-body theory. In this work we analytically construct classical networks for the description of the quantum dynamics in transverse-field Ising models that can be solved efficiently using Monte Carlo techniques. Our perturbative construction encodes time-evolved quantum states of spin-1/2 systems in a network of classical spins with local couplings and can be directly generalized to other spin systems and higher spins. Using this construction we compute the transient dynamics in one, two, and three dimensions including local observables, entanglement production, and Loschmidt amplitudes using Monte Carlo algorithms and demonstrate the accuracy of this approach by comparisons to exact results. We include a mapping to equivalent artificial neural networks, which were recently introduced to provide a universal structure for classical network wave functions.

  14. Development of teleoperated cleanup system

    International Nuclear Information System (INIS)

    Kim, Ki Ho; Park, J. J.; Yang, M. S.; Kwon, H. J.

    2005-01-01

    This report describes the development of a teleoperated cleanup system for use in a highly radioactive environment of DFDF(DUPIC Fuel Demonstration Facility) at KAERI where direct human access to the in-cell is strictly limited. The teleoperated cleanup system was designed to remotely remove contaminants placed or fixed on the floor surface of the hot-cell by mopping them with wet cloth. This cleanup system consists of a mopping slave, a mopping master and a control console. The mopping slave located at the in-cell comprises a mopping tool with a mopping cloth and a mobile platform, which were constructed in modules to facilitate maintenance. The mopping master that is an input device to control the mopping slave has kinematic dissimilarity with the mopping slave. The control console provides a means of bilateral control flows and communications between the mopping master and the mopping slave. In operation, the human operator from the out-of-cell performs a series of decontamination tasks remotely by manipulating the mopping slave located in-cell via a mopping master, having a sense of real mopping. The environmental and mechanical design considerations, and control systems of the developed teleoperated cleanup system are also described

  15. Networking systems design and development

    CERN Document Server

    Chao, Lee

    2009-01-01

    Effectively integrating theory and hands-on practice, Networking Systems Design and Development provides students and IT professionals with the knowledge and skills needed to design, implement, and manage fully functioning network systems using readily available Linux networking tools. Recognizing that most students are beginners in the field of networking, the text provides step-by-step instruction for setting up a virtual lab environment at home. Grounded in real-world applications, this book provides the ideal blend of conceptual instruction and lab work to give students and IT professional

  16. Managing Sustainable Information Systems Development

    DEFF Research Database (Denmark)

    Kautz, Karlheinz

    2013-01-01

    Sustainable information systems development (ISD) in the context of this paper is not about products that support sustainability at large with its environmental, economic and social dimensions and little about the development of sustainable products, which are both without doubt important topics....... This paper is about a prerequisite for such products, namely, a sustainable ISD process, a process which exhibits reasonable and responsible stewardship and utilisation of the existing resources for ISD—people and information in the context of scope, time/schedule, budget/cost, quality and risk....

  17. Negotiating a Systems Development Method

    Science.gov (United States)

    Karlsson, Fredrik; Hedström, Karin

    Systems development methods (or methods) are often applied in tailored version to fit the actual situation. Method tailoring is in most the existing literature viewed as either (a) a highly rational process with the method engineer as the driver where the project members are passive information providers or (b) an unstructured process where the systems developer makes individual choices, a selection process without any driver. The purpose of this chapter is to illustrate that important design decisions during method tailoring are made by project members through negotiation. The study has been carried out using the perspective of actor-network theory. Our narratives depict method tailoring as more complex than (a) and (b) show the driver role rotates between the project members, and design decisions are based on influences from several project members. However, these design decisions are not consensus decisions.

  18. Magnetic properties and thermodynamics of decorated Ising chain with pendants of arbitrary spin

    Energy Technology Data Exchange (ETDEWEB)

    Li Wei, E-mail: liwei-b09@mails.gucas.ac.c [College of Physical Sciences, Graduate University of Chinese Academy of Sciences, P.O. Box 4588, Beijing 100049 (China); Department of Physics, Beihang University, Beijing 100191 (China); Gong Shoushu [College of Physical Sciences, Graduate University of Chinese Academy of Sciences, P.O. Box 4588, Beijing 100049 (China); Chen Ziyu [Department of Physics, Beihang University, Beijing 100191 (China); Zhao Yang [College of Physical Sciences, Graduate University of Chinese Academy of Sciences, P.O. Box 4588, Beijing 100049 (China); Su Gang, E-mail: gsu@gucas.ac.c [College of Physical Sciences, Graduate University of Chinese Academy of Sciences, P.O. Box 4588, Beijing 100049 (China)

    2010-05-31

    The decorated Ising chain with pendants of arbitrary spin and the single-ion anisotropy is exactly solved by the transfer matrix method. The solutions reveal abundant novel properties than the conventional one-dimensional Ising model. It is compared with the experimental data of a necklace-like molecule-based magnet, that gives a qualitative consistency.

  19. Magnetic properties and thermodynamics of decorated Ising chain with pendants of arbitrary spin

    International Nuclear Information System (INIS)

    Li Wei; Gong Shoushu; Chen Ziyu; Zhao Yang; Su Gang

    2010-01-01

    The decorated Ising chain with pendants of arbitrary spin and the single-ion anisotropy is exactly solved by the transfer matrix method. The solutions reveal abundant novel properties than the conventional one-dimensional Ising model. It is compared with the experimental data of a necklace-like molecule-based magnet, that gives a qualitative consistency.

  20. Large Deviations for the Annealed Ising Model on Inhomogeneous Random Graphs: Spins and Degrees

    Science.gov (United States)

    Dommers, Sander; Giardinà, Cristian; Giberti, Claudio; Hofstad, Remco van der

    2018-04-01

    We prove a large deviations principle for the total spin and the number of edges under the annealed Ising measure on generalized random graphs. We also give detailed results on how the annealing over the Ising model changes the degrees of the vertices in the graph and show how it gives rise to interesting correlated random graphs.

  1. High temperature limit of the order parameter correlation functions in the quantum Ising model

    Science.gov (United States)

    Reyes, S. A.; Tsvelik, A. M.

    2006-06-01

    In this paper we use the exact results for the anisotropic two-dimensional Ising model obtained by Bugrii and Lisovyy [A.I. Bugrii, O.O. Lisovyy, Theor. Math. Phys. 140 (2004) 987] to derive the expressions for dynamical correlation functions for the quantum Ising model in one dimension at high temperatures.

  2. High temperature limit of the order parameter correlation functions in the quantum Ising model

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, S.A. [Department of Physics and Astronomy, SUNY at Stony Brook, Stony Brook, NY 11794-3840 (United States); Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Tsvelik, A.M. [Department of Physics and Astronomy, SUNY at Stony Brook, Stony Brook, NY 11794-3840 (United States) and Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, NY 11973-5000 (United States)]. E-mail tsvelik@bnl.gov

    2006-06-12

    In this paper we use the exact results for the anisotropic two-dimensional Ising model obtained by Bugrii and Lisovyy [A.I. Bugrii, O.O. Lisovyy, Theor. Math. Phys. 140 (2004) 987] to derive the expressions for dynamical correlation functions for the quantum Ising model in one dimension at high temperatures.

  3. Development of pipe layout system

    International Nuclear Information System (INIS)

    Ota, Yoshimi; Yamamoto, Shigeru; Tokumasu, Shinji; Yamaguchi, Yukio; Besho, Hiromi; Sakano, Tatuo.

    1986-01-01

    In the plant design carried out so far, the process up to final drawings has been the repetition of the correction of drawings. This is because the space as the object of design is finite, and it is difficult to lay many pipes efficiently. Especially in nuclear power plants, the quantity of materials required for ensuring the safety and quality control is enormous, and only the skilled engineers having rich experience have become unable to deal with it. The model engineering using plastic models has been adopted, but still there are problems. In order to solve this problem, the development of the system for unitarily managing the various design information of plants with a computer, checking up various design with this information, automatically outputting design drawings and management data, and heightening the quality of design, synchronizing the progress, increasing the speed and saving the labor of design was carried out. This system is versatile and can be used for all plants. The emphasis in the development was placed on compact data structure, rapid picture processing and easy operation. The present status of design and the automation, the basic design of the system, the function of the system, the internal expression of models, the method of picture processing, and the results of application are reported. (Kako, I.)

  4. Remote Arrhythmia Monitoring System Developed

    Science.gov (United States)

    York, David W.; Mackin, Michael A.; Liszka, Kathy J.; Lichter, Michael J.

    2004-01-01

    Telemedicine is taking a step forward with the efforts of team members from the NASA Glenn Research Center, the MetroHealth campus of Case Western University, and the University of Akron. The Arrhythmia Monitoring System is a completed, working test bed developed at Glenn that collects real-time electrocardiogram (ECG) signals from a mobile or homebound patient, combines these signals with global positioning system (GPS) location data, and transmits them to a remote station for display and monitoring. Approximately 300,000 Americans die every year from sudden heart attacks, which are arrhythmia cases. However, not all patients identified at risk for arrhythmias can be monitored continuously because of technological and economical limitations. Such patients, who are at moderate risk of arrhythmias, would benefit from technology that would permit long-term continuous monitoring of electrical cardiac rhythms outside the hospital environment. Embedded Web Technology developed at Glenn to remotely command and collect data from embedded systems using Web technology is the catalyst for this new telemetry system (ref. 1). In the end-to-end system architecture, ECG signals are collected from a patient using an event recorder and are transmitted to a handheld personal digital assistant (PDA) using Bluetooth, a short-range wireless technology. The PDA concurrently tracks the patient's location via a connection to a GPS receiver. A long distance link is established via a standard Internet connection over a 2.5-generation Global System for Mobile Communications/General Packet Radio Service (GSM/GPRS)1 cellular, wireless infrastructure. Then, the digital signal is transmitted to a call center for monitoring by medical professionals.

  5. Ising tricriticality in the extended Hubbard model with bond dimerization

    Science.gov (United States)

    Fehske, Holger; Ejima, Satoshi; Lange, Florian; Essler, Fabian H. L.

    We explore the quantum phase transition between Peierls and charge-density-wave insulating states in the one-dimensional, half-filled, extended Hubbard model with explicit bond dimerization. We show that the critical line of the continuous Ising transition terminates at a tricritical point, belonging to the universality class of the tricritical Ising model with central charge c=7/10. Above this point, the quantum phase transition becomes first order. Employing a numerical matrix-product-state based (infinite) density-matrix renormalization group method we determine the ground-state phase diagram, the spin and two-particle charge excitations gaps, and the entanglement properties of the model with high precision. Performing a bosonization analysis we can derive a field description of the transition region in terms of a triple sine-Gordon model. This allows us to derive field theory predictions for the power-law (exponential) decay of the density-density (spin-spin) and bond-order-wave correlation functions, which are found to be in excellent agreement with our numerical results. This work was supported by Deutsche Forschungsgemeinschaft (Germany), SFB 652, project B5, and by the EPSRC under Grant No. EP/N01930X/1 (FHLE).

  6. Evidence for two-dimensional ising structure in atomic nuclei

    International Nuclear Information System (INIS)

    MacGregor, M.H.

    1976-01-01

    Although the unpaired nucleons in an atomic nucleus exhibit pronounced shell-model-like behavior, the situation with respect to the paired-off ''core region'' nucleons is considerably more obscure. Several recent ''multi-alpha knockout'' and ''quasi-fission'' experiments indicate that nucleon clustering is prevalent throughout the core region of the nucleus; this same conclusion is suggested by nuclear-binding-energy systematics, by the evidence for a ''neutron halo'' in heavy nuclei and by the magnetic-moment systematics of low-mass odd-A nuclei. A number of arguments suggests, in turn, that this nucleon clustering is not spherical or spheroidal in shape, as has generally been assumed, but instead is in the form of two-dimensional Ising-like layers, with the layers arrayed perpendicular to the symmetry axis of the nucleus. The effects of this two-dimensional layering are observed most clearly in low-energy-induced fission, where nuclei with an even (odd) number of Ising layers fission symmetrically (asymmetrically). This picture of the nucleus gives an immediate quantitative explanation for the observed asymmetry in the fission of uranium, and also for the transition from symmetric to asymmetric and back to symmetric fission as the atomic number of the fissioning nuclues increase from A = 197 up to A = 258. These results suggest that, in the shell model formulation of the atomic nucleus, the basis states for the paired-off nucleon core region should be modified so as to contain laminar nucleon cluster correlations

  7. On the quantum symmetry of the chiral Ising model

    Science.gov (United States)

    Vecsernyés, Peter

    1994-03-01

    We introduce the notion of rational Hopf algebras that we think are able to describe the superselection symmetries of rational quantum field theories. As an example we show that a six-dimensional rational Hopf algebra H can reproduce the fusion rules, the conformal weights, the quantum dimensions and the representation of the modular group of the chiral Ising model. H plays the role of the global symmetry algebra of the chiral Ising model in the following sense: (1) a simple field algebra F and a representation π on Hπ of it is given, which contains the c = {1}/{2} unitary representations of the Virasoro algebra as subrepresentations; (2) the embedding U: H → B( Hπ) is such that the observable algebra π( A) - is the invariant subalgebra of B( Hπ) with respect to the left adjoint action of H and U(H) is the commutant of π( A); (3) there exist H-covariant primary fields in B( Hπ), which obey generalized Cuntz algebra properties and intertwine between the inequivalent sectors of the observables.

  8. Development of logistics information systems

    Directory of Open Access Journals (Sweden)

    Milan Ž. Dronjak

    2012-10-01

    -Army (Global Combat Support System-Army Field/Tactical, is intended for the tactical level and it will replace 14 tactical logistics information systems and connect them with the rest of the information environment. Tendencies in the development of logistics information systems In line with the presented information solutions, it is possible to extract relevant conclusions about tendencies in the development of these types of systems all around the world. These conclusions should be implemented, through adequate principles, into domestic software development. Three main tendencies are visible in modern solutions: using centralised databases, integration of existing separated software solutions, and connecting previously autonomus systems. Conclusion In accordance with present time requirements, logistic support should be realised as close as possible to the origin of a logistic need, in real time and adequately. Information systems enable real time delivery of information needed for a quality logistic support in all phases of operations as well as for a faster generation of all types of documents.

  9. Giant magnetocaloric effect, magnetization plateaux and jumps of the regular Ising polyhedra

    International Nuclear Information System (INIS)

    Strečka, Jozef; Karľová, Katarína; Madaras, Tomáš

    2015-01-01

    Magnetization process and adiabatic demagnetization of the antiferromagnetic Ising spin clusters with the shape of regular polyhedra (Platonic solids) are exactly examined within the framework of a simple graph-theoretical approach. While the Ising cube as the only unfrustrated (bipartite) spin cluster shows just one trivial plateau at zero magnetization, the other regular Ising polyhedra (tetrahedron, octahedron, icosahedron and dodecahedron) additionally display either one or two intermediate plateaux at fractional values of the saturation magnetization. The nature of highly degenerate ground states emergent at intermediate plateaux owing to a geometric frustration is clarified. It is evidenced that the regular Ising polyhedra exhibit a giant magnetocaloric effect in a vicinity of magnetization jumps, whereas the Ising octahedron and dodecahedron belong to the most prominent geometrically frustrated spin clusters that enable an efficient low-temperature refrigeration by the process of adiabatic demagnetization

  10. Magnetization in quenched bond-mixed Ising ferromagnetic with anisotropic coupling constants

    International Nuclear Information System (INIS)

    Sarmento, E.F.; Tsallis, C.

    1982-01-01

    Within the framework of an effective field theory the phase diagram (ferromagnetic phase stability limit) and magnetization of a quenched bond-mixed spin 1 / 2 Ising model in anisotropic simple cubic lattice for both competing and non competing interactions is dicussed. Although analytically simple, the present formalism is superior to the standard Mean Field Approximation regarding at least two important features, namely it is capable of providing: (i) vanishing critical temperatures for one-dimensional systems; (ii) expected non uniform convergences in the highly diluted and highly anisotropic limits. The largeness of the model under consideration enables the exhibition of a certain amount of physically interesting crossovers (dimensionality changements, (dilute) - (non dilute) behavior, or even mixed situations) at both the phase diagram and magnetization levels. Whenever comparison is possible a satisfactory qualitative (and to a certain extent quantitative) agreement is observed with results available in the literature. (Author) [pt

  11. Frozen into stripes: fate of the critical Ising model after a quench.

    Science.gov (United States)

    Blanchard, T; Picco, M

    2013-09-01

    In this article we study numerically the final state of the two-dimensional ferromagnetic critical Ising model after a quench to zero temperature. Beginning from equilibrium at T_{c}, the system can be blocked in a variety of infinitely long lived stripe states in addition to the ground state. Similar results have already been obtained for an infinite temperature initial condition and an interesting connection to exact percolation crossing probabilities has emerged. Here we complete this picture by providing an example of stripe states precisely related to initial crossing probabilities for various boundary conditions. We thus show that this is not specific to percolation but rather that it depends on the properties of spanning clusters in the initial state.

  12. Self-organization of domain growth in the Ising model with impurities

    DEFF Research Database (Denmark)

    Andersen, Jørgen Vitting; Mouritsen, Ole G.

    1992-01-01

    We have studied avalanchelike rearrangements of domain patterns in the two-dimensional Ising model with static impurities, which is quenched to low temperatures. When breaking the up-down symmetry of the spins by a small applied field, the mere fluctuation of a single spin eventually results...... in a cascade of spin flips at the domain boundaries. We have analyzed the lifetime and size distribution functions for the avalanches and related the results to the general phenomena of self-organized criticality and to recent experiments on cellular magnetic domain patterns in magnetic garnet films. Our...... results suggest that the self-organized state in this system appears to be subcritical, in agreement with a recent theory....

  13. Effective field theory with differential operator technique for dynamic phase transition in ferromagnetic Ising model

    International Nuclear Information System (INIS)

    Kinoshita, Takehiro; Fujiyama, Shinya; Idogaki, Toshihiro; Tokita, Masahiko

    2009-01-01

    The non-equilibrium phase transition in a ferromagnetic Ising model is investigated by use of a new type of effective field theory (EFT) which correctly accounts for all the single-site kinematic relations by differential operator technique. In the presence of a time dependent oscillating external field, with decrease of the temperature the system undergoes a dynamic phase transition, which is characterized by the period averaged magnetization Q, from a dynamically disordered state Q = 0 to the dynamically ordered state Q ≠ 0. The results of the dynamic phase transition point T c determined from the behavior of the dynamic magnetization and the Liapunov exponent provided by EFT are improved than that of the standard mean field theory (MFT), especially for the one dimensional lattice where the standard MFT gives incorrect result of T c = 0 even in the case of zero external field.

  14. Dynamical response of the Ising model to the time dependent magnetic field with white noise

    Science.gov (United States)

    Akıncı, Ümit

    2018-03-01

    The effect of the white noise in time dependent magnetic field on the dynamic behavior of the Ising model has been investigated within the effective field theory based on Glauber type of stochastic process. Discrete white noise has been chosen from both Gaussian and uniform probability distributions. Detailed investigation on probability distribution of dynamical order parameter results that, both type of noise distributions yield the same probability distribution related to the dynamical order parameter, namely Gaussian probability distribution. The variation of the parameters that describe the probability distribution of dynamical order parameter (mean value and standard deviation) with temperature and strength of the noise have been inspected. Also, it has been shown that, rising strength of the noise can induce dynamical phase transition in the system.

  15. Finite-size-scaling analysis of subsystem data in the dilute Ising model

    International Nuclear Information System (INIS)

    Hennecke, M.

    1993-01-01

    Monte Carlo simulation results for the magnetization of subsystems of finite lattices are used to determine the critical temperature and a critical exponent of the simple-cubic Ising model with quenched site dilution, at a concentration of p=40%. Particular attention is paid to the effect of the finite size of the systems from which the subsystem results are obtained. This finiteness of the lattices involved is shown to be a source of large deviations of critical temperatures and exponents estimated from subsystem data from their values in the thermodynamic limit. By the use of different lattice sizes, the results T c (40%)=1.209±0.002 and ν(40%)=0.78±0.01 could be extrapolated

  16. Blocked edges on Eulerian maps and mobiles: application to spanning trees, hard particles and the Ising model

    International Nuclear Information System (INIS)

    Bouttier, J; Francesco, P Di; Guitter, E

    2007-01-01

    We introduce Eulerian maps with blocked edges as a general way to implement statistical matter models on random maps by a modification of intrinsic distances. We show how to code these dressed maps by means of mobiles, i.e. decorated trees with labelled vertices, leading to a closed system of recursion relations for their generating functions. We discuss particular solvable cases in detail, as well as various applications of our method to several statistical systems such as spanning trees on quadrangulations, mutually excluding particles on Eulerian triangulations or the Ising model on quadrangulations

  17. KSTAR RF heating system development

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, J. G.; Kim, S. K.; Hwang, C. K. (and others)

    2007-10-15

    Design, high-voltage test, and installation of 6 MW ICRF heating system for KSTAR is completed. The antenna demonstrated satisfactory standoff at high voltages up to 41 kV for 300 sec. The result indicates good power handling capabilities of the antenna as high as 10 MW/m2. This power density is equivalent to RF power coupling of 6 MW into a 4 {omega}/m target plasma, and is typical of advanced tokamak heating scenarios. In addition, vacuum feed through, DC break, and liquid stub developed for 300 sec operation are installed, as well as a 2 MW, 30-60MHz transmitter. The transmitter successfully produced output powers of 600 kW continuously, 1.5{approx}1.8 MW for 300 sec, and 2 MW for 100 msec or shorter pulses. A realtime control system based on DSP and EPICS is developed, installed, and tested on the ICRF system. Initial results from feasibility study indicate that the present antenna and the transmission lines could allow load-resilient operation on KSTAR. Until the KSTAR tokamak start to produce plasmas in 2008, however, hands-on operational experiences are obtained from participating in ICRF heating experiments at ASDEX and DIII-D tokamaks arranged through international cooperation.

  18. Expert system development (ESD) shell

    International Nuclear Information System (INIS)

    Padmini, S.; Diwakar, M.P.; Rathode, N.C.; Bairi, B.R.

    1991-01-01

    An Expert System Development (ESD) Shell design implementation is desribed in detail. The shell provides high-level generic facilities for Knowledge Representation (KR) and inferencing and tools for developing user interfaces. Powerful set of tools in the shell relieves much of the programming burden in the ES development. The shell is written in PROLOG under IBM PC/AT. KR facilities are based on two very powerful formalisms namely, frames and rules. Inference Engine (IE) draws most of its power from unification and backward reasoning strategy in PROLOG. This basic mechanism is enhanced further by incorporating both forward and backward chaining of rules and frame-based inferencing. Overall programming style integrates multiple paradigms including logic, object oriented, access-oriented and imperative programming. This permits ES designer a lot of flexibility in organizing inference control. Creation and maintainance of knowledge base is a major activity. The shell, therefore, provides number of facilities to simplify these tasks. Shell design also takes note of the fact that final success of any system depends on end-user satisfaction and hence provides features to build use-friendly interfaces. The shell also provides a set of interfacing predicates so that it can be embedded within any PROLOG program to incorporate functionalilty of the shell in the user program. (author). 10 refs., 8 figs

  19. Magnetization plateaus and phase diagrams of the Ising model on the Shastry–Sutherland lattice

    Energy Technology Data Exchange (ETDEWEB)

    Deviren, Seyma Akkaya, E-mail: sadeviren@nevsehir.edu.tr

    2015-11-01

    The magnetization properties of a two-dimensional spin-1/2 Ising model on the Shastry–Sutherland lattice are studied within the effective-field theory (EFT) with correlations. The thermal behavior of the magnetizations is investigated in order to characterize the nature (the first- or second-order) of the phase transitions as well as to obtain the phase diagrams of the model. The internal energy, specific heat, entropy and free energy of the system are also examined numerically as a function of the temperature in order to confirm the stability of the phase transitions. The applied field dependence of the magnetizations is also examined to find the existence of the magnetization plateaus. For strong enough magnetic fields, several magnetization plateaus are observed, e.g., at 1/9, 1/8, 1/3 and 1/2 of the saturation. The phase diagrams of the model are constructed in two different planes, namely (h/|J|, |J′|/|J|) and (h/|J|, T/|J|) planes. It was found that the model exhibits first- and second-order phase transitions; hence tricitical point is also observed in additional to the zero-temperature critical point. Moreover the Néel order (N), collinear order (C) and ferromagnetic (F) phases are also found with appropriate values of the system parameters. The reentrant behavior is also obtained whenever model displays two Néel temperatures. These results are compared with some theoretical and experimental works and a good overall agreement has been obtained. - Highlights: • Magnetization properties of spin-1/2 Ising model on SS lattice are investigated. • The magnetization plateaus of the 1/9, 1/8, 1/3 and 1/2 are observed. • The phase diagrams of the model are constructed in two different planes. • The model exhibits the tricitical and zero-temperature critical points. • The reentrant behavior is obtained whenever model displays two Neel temperatures.

  20. Development of controlled drilling system

    International Nuclear Information System (INIS)

    Kiho, Kenzo; Miyakawa, Kimio; Suzuki, Koichi; Sunaga, Takayuki

    2008-01-01

    In Japan, the soft sedimentary rock of the Neogene tertiary is being focused as a host rock for the High Level Radioactive Waste (HLW) disposal. Especially, the soft sedimentary rock at the offshore, region is thought to be one of the best candidates, since there is no driving force of the underground water. The measurement and logging in the bore hole in order to check the hydro-geological and geomechanical conditions of the host rock is a very important way to examine the potentially of the disposal candidates. The CRIEPI (Central Research Institute of Electric Power Industry) has been conducting the project about the controlled drilling technology and the measurement and logging technologies in its borehole. In 2000, as the beginning year of the project, we made the conceptual design of the drilling and measuring systems, and made key tools concerning each technology on an experimental basis. We have been developing sub tools constructing drilling and measuring systems since 2000, and applying these systems to the Horonobe site recent 5 years. We will briefly report the outline of the system and the results of drilling and measurement that were carried out at the Horonobe site. (author)

  1. Development of targeted radiotherapy systems

    International Nuclear Information System (INIS)

    Ferro, Guillermina; Villarreal, Jose E.; Garcia, Laura; Tendilla, Jose I.; Paredes, Lydia; Murphy, Consuelo A.; Pedraza, Martha

    2001-01-01

    Conventional or external beam radiotherapy, has been a viable alternative for cancer treatment. Although this technique is effective, its use is limited if the patient has multiple malignant lesions (metastases). An alternative approach is based on the design of radiopharmaceuticals that, to be administered in the patient, are directed specifically toward the target cell producing a selective radiation delivery. This treatment is known as targeted radiotherapy. We have summarized and discussed some results related to our investigations on the development of targeted radiotherapy systems, including aspects of internal dosimetry

  2. Computer aided training system development

    International Nuclear Information System (INIS)

    Midkiff, G.N.

    1987-01-01

    The first three phases of Training System Development (TSD) -- job and task analysis, curriculum design, and training material development -- are time consuming and labor intensive. The use of personal computers with a combination of commercial and custom-designed software resulted in a significant reduction in the man-hours required to complete these phases for a Health Physics Technician Training Program at a nuclear power station. This paper reports that each step in the training program project involved the use of personal computers: job survey data were compiled with a statistical package, task analysis was performed with custom software designed to interface with a commercial database management program. Job Performance Measures (tests) were generated by a custom program from data in the task analysis database, and training materials were drafted, edited, and produced using commercial word processing software

  3. A hidden Ising model for ChIP-chip data analysis

    KAUST Repository

    Mo, Q.

    2010-01-28

    Motivation: Chromatin immunoprecipitation (ChIP) coupled with tiling microarray (chip) experiments have been used in a wide range of biological studies such as identification of transcription factor binding sites and investigation of DNA methylation and histone modification. Hidden Markov models are widely used to model the spatial dependency of ChIP-chip data. However, parameter estimation for these models is typically either heuristic or suboptimal, leading to inconsistencies in their applications. To overcome this limitation and to develop an efficient software, we propose a hidden ferromagnetic Ising model for ChIP-chip data analysis. Results: We have developed a simple, but powerful Bayesian hierarchical model for ChIP-chip data via a hidden Ising model. Metropolis within Gibbs sampling algorithm is used to simulate from the posterior distribution of the model parameters. The proposed model naturally incorporates the spatial dependency of the data, and can be used to analyze data with various genomic resolutions and sample sizes. We illustrate the method using three publicly available datasets and various simulated datasets, and compare it with three closely related methods, namely TileMap HMM, tileHMM and BAC. We find that our method performs as well as TileMap HMM and BAC for the high-resolution data from Affymetrix platform, but significantly outperforms the other three methods for the low-resolution data from Agilent platform. Compared with the BAC method which also involves MCMC simulations, our method is computationally much more efficient. Availability: A software called iChip is freely available at http://www.bioconductor.org/. Contact: moq@mskcc.org. © The Author 2010. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org.

  4. Microscopic image processing system for measuring nonuniform film thickness profiles: Image scanning ellipsometry

    International Nuclear Information System (INIS)

    Liu, A.H.; Plawsky, J.L.; Wayner, P.C. Jr.

    1993-01-01

    The long-term objective of this research program is to determine the stability and heat transfer characteristics of evaporating thin films. The current objective is to develop and use a microscopic image-processing system (IPS) which has two parts: an image analyzing interferometer (IAI) and an image scanning ellipsometer (ISE). The primary purpose of this paper is to present the basic concept of ISE, which is a novel technique to measure the two dimensional thickness profile of a non-uniform, thin film, from several nm up to several μm, in a steady state as well as in a transient state. It is a full-field imaging technique which can study every point on the surface simultaneously with high spatial resolution and thickness sensitivity, i.e., it can measure and map the 2-D film thickness profile. The ISE was tested by measuring the thickness profile and the refractive index of a nonuniform solid film

  5. ADASAGE, ADA Application Development System

    International Nuclear Information System (INIS)

    Taylor, M.; Russell, K.; Stewart, H.

    2001-01-01

    1 - Description of program or function: ADASAGE is an application development system designed to facilitate rapid and professional construction of applications written in Ada on microcomputers. ADASAGE applications may vary in size from small to large multi-program systems. ADASAGE consists of a collection of re-usable libraries for database management and form and report processing utilities having the following capabilities: basic universal type and function definitions; sequential file input/output; terminal and file input/output; DOS system command execution; data movement and fill; string manipulation; math libraries; bit manipulation; a relational database utility; data validation; menu form and window procedures; report generation; sort/merge, time, and date functions; sound production; editing; and index rebuilding. Each of the capabilities is integrated to allow the development of an efficient system. As an application is designed and developed, the desired ADASAGE capabilities are chosen and included along with any requirements unique to that application. 2 - Method of solution: All ADASAGE applications which use the database, forms (windows, menus, etc.), or reporting functions require a file with a suffix of .DFL. This file contains the database schema, the various forms and windows, and report definitions. The THOR editor is used to create and maintain the .DFL file. This editor operates on a file with the suffix .SRC and creates and edits schemes, forms, and report formats and compile the .SRC file into the .DFL file used by the application. The application will have unique requirements not satisfied by the selected utilities of ADASAGE. The code for these along with the code necessary to import and use the selected ADASAGE utilities constitutes the p rogrammed application . The completed application system will contain the .DFL file produced by the THOR editor, the required ADASAGE utilities, and the programmed application. During the course of

  6. Quantum Annealing and Quantum Fluctuation Effect in Frustrated Ising Systems

    OpenAIRE

    Tanaka, Shu; Tamura, Ryo

    2012-01-01

    Quantum annealing method has been widely attracted attention in statistical physics and information science since it is expected to be a powerful method to obtain the best solution of optimization problem as well as simulated annealing. The quantum annealing method was incubated in quantum statistical physics. This is an alternative method of the simulated annealing which is well-adopted for many optimization problems. In the simulated annealing, we obtain a solution of optimization problem b...

  7. Simple method to calculate percolation, Ising and Potts clusters

    International Nuclear Information System (INIS)

    Tsallis, C.

    1981-01-01

    A procedure ('break-collapse method') is introduced which considerably simplifies the calculation of two - or multirooted clusters like those commonly appearing in real space renormalization group (RG) treatments of bond-percolation, and pure and random Ising and Potts problems. The method is illustrated through two applications for the q-state Potts ferromagnet. The first of them concerns a RG calculation of the critical exponent ν for the isotropic square lattice: numerical consistence is obtained (particularly for q→0) with den Nijs conjecture. The second application is a compact reformulation of the standard star-triangle and duality transformations which provide the exact critical temperature for the anisotropic triangular and honeycomb lattices. (Author) [pt

  8. String effects in the 3d gauge Ising model

    International Nuclear Information System (INIS)

    Caselle, Michele; Panero, Marco; Hasenbusch, Martin

    2003-01-01

    We compare the predictions of the effective string description of confinement with a set of Monte Carlo data for the 3d gauge Ising model at finite temperature. Thanks to a new algorithm which makes use of the dual symmetry of the model we can reach very high precisions even for large quark-antiquark distances. We are thus able to explore the large R regime of the effective string. We find that for large enough distances and low enough temperature the data are well described by a pure bosonic string. As the temperature increases higher order corrections become important and cannot be neglected even at large distances. These higher order corrections seem to be well described by the Nambu-Goto action truncated at the first perturbative order. (author)

  9. Effective-field theory on the kinetic Ising model

    International Nuclear Information System (INIS)

    Shi Xiaoling; Wei Guozhu; Li Lin

    2008-01-01

    As an analytical method, the effective-field theory (EFT) is used to study the dynamical response of the kinetic Ising model in the presence of a sinusoidal oscillating field. The effective-field equations of motion of the average magnetization are given for the square lattice (Z=4) and the simple cubic lattice (Z=6), respectively. The dynamic order parameter, the hysteresis loop area and the dynamic correlation are calculated. In the field amplitude h 0 /ZJ-temperature T/ZJ plane, the phase boundary separating the dynamic ordered and the disordered phase has been drawn, and the dynamical tricritical point has been observed. We also make the compare results of EFT with that given by using the mean field theory (MFT)

  10. Large-scale Ising-machines composed of magnetic neurons

    Science.gov (United States)

    Mizushima, Koichi; Goto, Hayato; Sato, Rie

    2017-10-01

    We propose Ising-machines composed of magnetic neurons, that is, magnetic bits in a recording track. In large-scale machines, the sizes of both neurons and synapses need to be reduced, and neat and smart connections among neurons are also required to achieve all-to-all connectivity among them. These requirements can be fulfilled by adopting magnetic recording technologies such as race-track memories and skyrmion tracks because the area of a magnetic bit is almost two orders of magnitude smaller than that of static random access memory, which has normally been used as a semiconductor neuron, and the smart connections among neurons are realized by using the read and write methods of these technologies.

  11. On the phase transition nature in compressible Ising models

    International Nuclear Information System (INIS)

    Ota, A.T.

    1985-01-01

    The phase transition phenomenon is analysed in a compressible ferromagnetic Ising model at null field, through the mean-field approximation. The model studied is d-dimensional under the magnetic point of view and one-dimensional under the elastic point of view. This is achieved keeping the compressive interactions among the ions and rejecting annealing forces completely. The exchange parameter J is linear and the elastic potential quadratic in relation to the microscopic shifts of the lattice. In the one-dimensional case, this model shows no phase transition. In the two-dimensional case, the role of the S i spin of the i-the ion is crucial: a) for spin 1/2 the transitions are of second order; b) for spin 1, desides the second order transitions there is a three-critical point and a first-order transitions line. (L.C.) [pt

  12. Thermal contact through a two-temperature kinetic Ising chain

    Science.gov (United States)

    Bauer, M.; Cornu, F.

    2018-05-01

    We consider a model for thermal contact through a diathermal interface between two macroscopic bodies at different temperatures: an Ising spin chain with nearest neighbor interactions is endowed with a Glauber dynamics with different temperatures and kinetic parameters on alternating sites. The inhomogeneity of the kinetic parameter is a novelty with respect to the model of Racz and Zia (1994 Phys. Rev. E 49 139), and we exhibit its influence upon the stationary non equilibrium values of the two-spin correlations at any distance. By mapping to the dynamics of spin domain walls and using free fermion techniques, we determine the scaled generating function for the cumulants of the exchanged heat amounts per unit of time in the long time limit.

  13. Random field Ising chain and neutral networks with synchronous dynamics

    International Nuclear Information System (INIS)

    Skantzos, N.S.; Coolen, A.C.C.

    2001-01-01

    We first present an exact solution of the one-dimensional random-field Ising model in which spin-updates are made fully synchronously, i.e. in parallel (in contrast to the more conventional Glauber-type sequential rules). We find transitions where the support of local observables turns from a continuous interval into a Cantor set and we show that synchronous and sequential random-field models lead asymptotically to the same physical states. We then proceed to an application of these techniques to recurrent neural networks where 1D short-range interactions are combined with infinite-range ones. Due to the competing interactions these models exhibit phase diagrams with first-order transitions and regions with multiple locally stable solutions for the macroscopic order parameters

  14. Ising formulation of associative memory models and quantum annealing recall

    Science.gov (United States)

    Santra, Siddhartha; Shehab, Omar; Balu, Radhakrishnan

    2017-12-01

    Associative memory models, in theoretical neuro- and computer sciences, can generally store at most a linear number of memories. Recalling memories in these models can be understood as retrieval of the energy minimizing configuration of classical Ising spins, closest in Hamming distance to an imperfect input memory, where the energy landscape is determined by the set of stored memories. We present an Ising formulation for associative memory models and consider the problem of memory recall using quantum annealing. We show that allowing for input-dependent energy landscapes allows storage of up to an exponential number of memories (in terms of the number of neurons). Further, we show how quantum annealing may naturally be used for recall tasks in such input-dependent energy landscapes, although the recall time may increase with the number of stored memories. Theoretically, we obtain the radius of attractor basins R (N ) and the capacity C (N ) of such a scheme and their tradeoffs. Our calculations establish that for randomly chosen memories the capacity of our model using the Hebbian learning rule as a function of problem size can be expressed as C (N ) =O (eC1N) , C1≥0 , and succeeds on randomly chosen memory sets with a probability of (1 -e-C2N) , C2≥0 with C1+C2=(0.5-f ) 2/(1 -f ) , where f =R (N )/N , 0 ≤f ≤0.5 , is the radius of attraction in terms of the Hamming distance of an input probe from a stored memory as a fraction of the problem size. We demonstrate the application of this scheme on a programmable quantum annealing device, the D-wave processor.

  15. Space Launch System Development Status

    Science.gov (United States)

    Lyles, Garry

    2014-01-01

    Development of NASA's Space Launch System (SLS) heavy lift rocket is shifting from the formulation phase into the implementation phase in 2014, a little more than three years after formal program approval. Current development is focused on delivering a vehicle capable of launching 70 metric tons (t) into low Earth orbit. This "Block 1" configuration will launch the Orion Multi-Purpose Crew Vehicle (MPCV) on its first autonomous flight beyond the Moon and back in December 2017, followed by its first crewed flight in 2021. SLS can evolve to a130-t lift capability and serve as a baseline for numerous robotic and human missions ranging from a Mars sample return to delivering the first astronauts to explore another planet. Benefits associated with its unprecedented mass and volume include reduced trip times and simplified payload design. Every SLS element achieved significant, tangible progress over the past year. Among the Program's many accomplishments are: manufacture of Core Stage test panels; testing of Solid Rocket Booster development hardware including thrust vector controls and avionics; planning for testing the RS-25 Core Stage engine; and more than 4,000 wind tunnel runs to refine vehicle configuration, trajectory, and guidance. The Program shipped its first flight hardware - the Multi-Purpose Crew Vehicle Stage Adapter (MSA) - to the United Launch Alliance for integration with the Delta IV heavy rocket that will launch an Orion test article in 2014 from NASA's Kennedy Space Center. Objectives of this Earth-orbit flight include validating the performance of Orion's heat shield and the MSA design, which will be manufactured again for SLS missions to deep space. The Program successfully completed Preliminary Design Review in 2013 and Key Decision Point C in early 2014. NASA has authorized the Program to move forward to Critical Design Review, scheduled for 2015 and a December 2017 first launch. The Program's success to date is due to prudent use of proven

  16. Effective-field theory of the Ising model with three alternative layers on the honeycomb and square lattices

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-09-15

    The Ising model with three alternative layers on the honeycomb and square lattices is studied by using the effective-field theory with correlations. We consider that the nearest-neighbor spins of each layer are coupled ferromagnetically and the adjacent spins of the nearest-neighbor layers are coupled either ferromagnetically or anti-ferromagnetically depending on the sign of the bilinear exchange interactions. We investigate the thermal variations of the magnetizations and present the phase diagrams. The phase diagrams contain the paramagnetic, ferromagnetic and anti-ferromagnetic phases, and the system also exhibits a tricritical behavior.

  17. Effective-field theory of the Ising model with three alternative layers on the honeycomb and square lattices

    International Nuclear Information System (INIS)

    Deviren, Bayram; Canko, Osman; Keskin, Mustafa

    2008-01-01

    The Ising model with three alternative layers on the honeycomb and square lattices is studied by using the effective-field theory with correlations. We consider that the nearest-neighbor spins of each layer are coupled ferromagnetically and the adjacent spins of the nearest-neighbor layers are coupled either ferromagnetically or anti-ferromagnetically depending on the sign of the bilinear exchange interactions. We investigate the thermal variations of the magnetizations and present the phase diagrams. The phase diagrams contain the paramagnetic, ferromagnetic and anti-ferromagnetic phases, and the system also exhibits a tricritical behavior

  18. The Ising model on a random planar lattice: The structure of the phase transition and the exact critical exponents

    International Nuclear Information System (INIS)

    Boulatov, D.V.; Kazakov, V.A.

    1987-01-01

    We investigate the critical properties of a recently proposed exactly soluble Ising model on a planar random dynamical lattice representing a regularization of the zero-dimensional string with internal fermions. The sum over all lattices gives rise to a new quantum degree of freedom - fluctuation of the metric. The whole system of critical exponents is found: α = -1, β = 1/2, γ = 2, δ = 5, v . D = 3. To test the universality we have used the planar graphs with the coordination number equal to 4 (Φ 4 theory graphs) as well as with the equal to 3 (Φ 3 theory graphs or triangulations). The critical exponents coincide for both cases. (orig.)

  19. Study of the time evolution of correlation functions of the transverse Ising chain with ring frustration by perturbative theory

    Science.gov (United States)

    Zheng, Zhen-Yu; Li, Peng

    2018-04-01

    We consider the time evolution of two-point correlation function in the transverse-field Ising chain (TFIC) with ring frustration. The time-evolution procedure we investigated is equivalent to a quench process in which the system is initially prepared in a classical kink state and evolves according to the time-dependent Schrödinger equation. Within a framework of perturbative theory (PT) in the strong kink phase, the evolution of the correlation function is disclosed to demonstrate a qualitatively new behavior in contrast to the traditional case without ring frustration.

  20. Size effects in spin-crossover nanoparticles in framework of 2D and 3D Ising-like breathing crystal field model

    International Nuclear Information System (INIS)

    Gudyma, Iu.; Maksymov, A.; Spinu, L.

    2015-01-01

    Highlights: • We study the thermal hysteresis in spin-crossover nanoparticles with stochastic perturbation. • The dependence of system behavior on its dimensionality and size were examined. • The spin-crossover compounds where described by breathing crystal field Ising-like model. • The fluctuations may enlarge the hysteresis width which is dependent on the system size. - Abstract: The spin-crossover nanoparticles of different sizes and stochastic perturbations in external field taking into account the influence of the dimensionality of the lattice was studied. The analytical tools used for the investigation of spin-crossover system are based on an Ising-like model described using of the breathing crystal field concept. The changes of transition temperatures characterizing the systems’ bistable properties for 2D and 3D lattices, and their dependence on its size and fluctuations strength were obtained. The state diagrams with hysteretic and non-hysteretic behavior regions have also been determined.

  1. Size effects in spin-crossover nanoparticles in framework of 2D and 3D Ising-like breathing crystal field model

    Energy Technology Data Exchange (ETDEWEB)

    Gudyma, Iu. [Department of General Physics, Chernivtsi National University, Chernivtsi 58012 (Ukraine); Maksymov, A., E-mail: maxyartur@gmail.com [Department of General Physics, Chernivtsi National University, Chernivtsi 58012 (Ukraine); Advanced Material Research Institute (AMRI), University of New Orleans, New Orleans, LA 70148 (United States); Spinu, L. [Advanced Material Research Institute (AMRI), University of New Orleans, New Orleans, LA 70148 (United States); Department of Physics, University of New Orleans, New Orleans, LA 70148 (United States)

    2015-10-15

    Highlights: • We study the thermal hysteresis in spin-crossover nanoparticles with stochastic perturbation. • The dependence of system behavior on its dimensionality and size were examined. • The spin-crossover compounds where described by breathing crystal field Ising-like model. • The fluctuations may enlarge the hysteresis width which is dependent on the system size. - Abstract: The spin-crossover nanoparticles of different sizes and stochastic perturbations in external field taking into account the influence of the dimensionality of the lattice was studied. The analytical tools used for the investigation of spin-crossover system are based on an Ising-like model described using of the breathing crystal field concept. The changes of transition temperatures characterizing the systems’ bistable properties for 2D and 3D lattices, and their dependence on its size and fluctuations strength were obtained. The state diagrams with hysteretic and non-hysteretic behavior regions have also been determined.

  2. Strong coupling expansion for scattering phases in hamiltonian lattice field theories. Pt. 1. The (d+1)-dimensional Ising model

    International Nuclear Information System (INIS)

    Dahmen, Bernd

    1994-01-01

    A systematic method to obtain strong coupling expansions for scattering quantities in hamiltonian lattice field theories is presented. I develop the conceptual ideas for the case of the hamiltonian field theory analogue of the Ising model, in d space and one time dimension. The main result is a convergent series representation for the scattering states and the transition matrix. To be explicit, the special cases of d=1 and d=3 spatial dimensions are discussed in detail. I compute the next-to-leading order approximation for the phase shifts. The application of the method to investigate low-energy scattering phenomena in lattice gauge theory and QCD is proposed. ((orig.))

  3. Frustrated spin systems

    CERN Document Server

    2013-01-01

    This book covers all principal aspects of currently investigated frustrated systems, from exactly solved frustrated models to real experimental frustrated systems, going through renormalization group treatment, Monte Carlo investigation of frustrated classical Ising and vector spin models, low-dimensional systems, spin ice and quantum spin glass. The reader can - within a single book - obtain a global view of the current research development in the field of frustrated systems.This new edition is updated with recent theoretical, numerical and experimental developments in the field of frustrated

  4. Systems of Systems: Scaling Up the Development Process

    National Research Council Canada - National Science Library

    Humphrey, Watts

    2006-01-01

    ... of massive systems into system-of-systems structures Section 3 points out how large-scale systems development efforts have typically failed because of project-management and not technical problems...

  5. Efficient generation of series expansions for ±J Ising spin glasses in a classical or a quantum field

    Science.gov (United States)

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

    2017-12-01

    We discuss generation of series expansions for Ising spin glasses with a symmetric ±J (i.e., bimodal) distribution on d -dimensional hypercubic lattices using linked-cluster methods. Simplifications for the bimodal distribution allow us to go to higher order than for a general distribution. We discuss two types of problems, one classical and one quantum. The classical problem is that of the Ising spin glass in a longitudinal magnetic field h , for which we obtain high temperature series expansions in variables tanh(J /T ) and tanh(h /T ) . The quantum problem is a T =0 study of the Ising spin glass in a transverse magnetic field hT for which we obtain a perturbation theory in powers of J /hT . These methods require (i) enumeration and counting of all connected clusters that can be embedded in the lattice up to some order n , and (ii) an evaluation of the contribution of each cluster for the quantity being calculated, known as the weight. We discuss a general method that takes the much smaller list (and count) of all no free-end (NFE) clusters on a lattice up to some order n and automatically generates all other clusters and their counts up to the same order. The weights for finite clusters in both cases have a simple graphical interpretation that allows us to proceed efficiently for a general configuration of the ±J bonds and at the end perform suitable disorder averaging. The order of our computations is limited by the weight calculations for the high-temperature expansions of the classical model, while they are limited by graph counting for the T =0 quantum system. Details of the calculational methods are presented.

  6. Size dependent thermal hysteresis in spin crossover nanoparticles reflected within a Monte Carlo based Ising-like model

    International Nuclear Information System (INIS)

    Atitoaie, Alexandru; Tanasa, Radu; Enachescu, Cristian

    2012-01-01

    Spin crossover compounds are photo-magnetic bistable molecular magnets with two states in thermodynamic competition: the diamagnetic low-spin state and paramagnetic high-spin state. The thermal transition between the two states is often accompanied by a wide hysteresis, premise for possible application of these materials as recording media. In this paper we study the influence of the system's size on the thermal hysteresis loops using Monte Carlo simulations based on an Arrhenius dynamics applied for an Ising like model with long- and short-range interactions. We show that using appropriate boundary conditions it is possible to reproduce both the drop of hysteresis width with decreasing particle size, the hysteresis shift towards lower temperatures and the incomplete transition, as in the available experimental data. The case of larger systems composed by several sublattices is equally treated reproducing the shrinkage of the hysteresis loop's width experimentally observed. - Highlights: ► A study concerning size effects in spin crossover nanoparticles hysteresis is presented. ► An Ising like model with short- and long-range interactions and Arrhenius dynamics is employed. ► In open boundary system the hysteresis width decreases with particle size. ► With appropriate environment, hysteresis loop is shifted towards lower temperature and transition is incomplete.

  7. Thermal and magnetic properties of ternary mixed Ising nanoparticles with core–shell structure: Effective-field theory approach

    International Nuclear Information System (INIS)

    Kantar, Ersin; Keskin, Mustafa

    2014-01-01

    We propose a ternary Ising spins (1/2, 1, 3/2) model to investigate the thermal and magnetic properties of magnetic nanoparticles with core–shell structure within the framework of the effective-field theory with correlations. The center site of the core is occupied by σ=±1/2 spin, while those surrounding the center site are occupied by S=±1, 0 spins and the shell sites are occupied by m=±1/2,±3/2 spins. Thermal behaviors of the core and shell magnetizations, susceptibilities and internal energies as well as total magnetization are examined. In order to confirm the stability of the solutions we also investigate the free energy of the system. According to the values of Hamiltonian parameters, the system undergoes first- and second-order phase transitions. Phase diagrams are calculated and discussed in detail. We find that the system exhibits a tricritical point, reentrant and five different type (Q, P, R, S and W) of compensation behaviors that strongly depend on interaction parameters. The results are in good agreement with some experimental and theoretical results. - Highlights: • Thermal and magnetic properties of ternary Ising nanoparticles are studied. • Phase diagrams within the EFT with correlations are calculated and discussed. • The effects of the exchange interactions and crystal field have been studied. • Reentrant phenomena and compensation behaviors have been found

  8. Thermal and magnetic properties of ternary mixed Ising nanoparticles with core–shell structure: Effective-field theory approach

    Energy Technology Data Exchange (ETDEWEB)

    Kantar, Ersin [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Institute of Science, Erciyes University, 38039 Kayseri (Turkey); Keskin, Mustafa, E-mail: keskin@erciyes.edu.tr [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

    2014-01-15

    We propose a ternary Ising spins (1/2, 1, 3/2) model to investigate the thermal and magnetic properties of magnetic nanoparticles with core–shell structure within the framework of the effective-field theory with correlations. The center site of the core is occupied by σ=±1/2 spin, while those surrounding the center site are occupied by S=±1, 0 spins and the shell sites are occupied by m=±1/2,±3/2 spins. Thermal behaviors of the core and shell magnetizations, susceptibilities and internal energies as well as total magnetization are examined. In order to confirm the stability of the solutions we also investigate the free energy of the system. According to the values of Hamiltonian parameters, the system undergoes first- and second-order phase transitions. Phase diagrams are calculated and discussed in detail. We find that the system exhibits a tricritical point, reentrant and five different type (Q, P, R, S and W) of compensation behaviors that strongly depend on interaction parameters. The results are in good agreement with some experimental and theoretical results. - Highlights: • Thermal and magnetic properties of ternary Ising nanoparticles are studied. • Phase diagrams within the EFT with correlations are calculated and discussed. • The effects of the exchange interactions and crystal field have been studied. • Reentrant phenomena and compensation behaviors have been found.

  9. Kuum IT-trend 2007 - see oled sina ise! / Andrus Hiiepuu, Ants Sild

    Index Scriptorium Estoniae

    Hiiepuu, Andrus, 1966-

    2007-01-01

    Ajakiri Time kuulutas aasta inimeseks tavalise arvutikasutaja, autorid arutlevad, mida see sina ise IT-vallas võiks tähendada. Infotainment - infotehnoloogia -ja kommunikatsioonivahendite ning meelelahutuse sulandumine

  10. Stability and replica symmetry in the ising spin glass: a toy model

    International Nuclear Information System (INIS)

    De Dominicis, C.; Mottishaw, P.

    1986-01-01

    Searching for possible replica symmetric solutions in an Ising spin glass (in the tree approximation) we investigate a toy model whose bond distribution has two non vanishing cumulants (instead of one only as in a gaussian distribution)

  11. The Influence of Participation in Sustainability Index (ISE in the Financial Performance of Business

    Directory of Open Access Journals (Sweden)

    Juliana Tatiane Vital

    2009-12-01

    Full Text Available This article aims to compare the performance, through certain financial indicators, including companies in the guide of the 500 biggest and best companies of Exame Magazine, forming part of the Corporate Sustainability Index (ISE and companies who do not. The primary purpose of ISE is to see the return of a portfolio composed of shares of companies committed to social responsibility and corporate sustainability. This research is classified as being descriptive and largely qualitative. The financial indicators examined in this study were: sales (value and growth, Net Income, Profitability, Net Working Capital, Liquidity, General Debt, Long Term Debt, EBITA and Indicators of export. After the analysis we can conclude that the companies participating in the ISE have greater potential for sales and exports. Companies that are not part of the ISE have better financial performance.

  12. Ising model of a randomly triangulated random surface as a definition of fermionic string theory

    International Nuclear Information System (INIS)

    Bershadsky, M.A.; Migdal, A.A.

    1986-01-01

    Fermionic degrees of freedom are added to randomly triangulated planar random surfaces. It is shown that the Ising model on a fixed graph is equivalent to a certain Majorana fermion theory on the dual graph. (orig.)

  13. Cluster-cluster aggregation of Ising dipolar particles under thermal noise

    KAUST Repository

    Suzuki, Masaru; Kun, Ferenc; Ito, Nobuyasu

    2009-01-01

    The cluster-cluster aggregation processes of Ising dipolar particles under thermal noise are investigated in the dilute condition. As the temperature increases, changes in the typical structures of clusters are observed from chainlike (D1

  14. Development of autonomous operation system

    International Nuclear Information System (INIS)

    Endou, Akira; Watanabe, Kenshiu; Miki, Tetsushi

    1992-01-01

    To enhance operation reliability of nuclear plants by removing human factors, study on an autonomous operation system has been carried out to substitute artificial intelligence (AI) for plant operators and, in addition, traditional controllers used in existing plants. For construction of the AI system, structurization of knowledge on the basis of the principles such as physical laws, function and structure of relevant objects and generalization of problem solving process are intended. A hierarchical distributed cooperative system configuration in employed because it is superior from the viewpoint of dynamical reorganization of system functions. This configuration is realized by an object-oriented multi-agent system. Construction of a prototype system was planned and the conceptual design was made for FBR plant in order to evaluate applicability of AI to the autonomous operation and to have a prospect for the realization of the system. The prototype system executes diagnosis, state evaluation, operation and control for the main plant subsystems. (author)

  15. Developing a Webfires Training System

    Science.gov (United States)

    2017-06-01

    8  Figure 2.  Waterfall Process Model. ...........................................................................11  Figure 3.  Spiral ...training system (WFTS). The third chapter in this section provides an overview of the purpose and methodology of the future training system. Chapter...Waterfall Process Model. b. Spiral Model The second systems engineering process model is the spiral process model. According to Blanchard and Fabrycky

  16. Test of quantum thermalization in the two-dimensional transverse-field Ising model.

    Science.gov (United States)

    Blaß, Benjamin; Rieger, Heiko

    2016-12-01

    We study the quantum relaxation of the two-dimensional transverse-field Ising model after global quenches with a real-time variational Monte Carlo method and address the question whether this non-integrable, two-dimensional system thermalizes or not. We consider both interaction quenches in the paramagnetic phase and field quenches in the ferromagnetic phase and compare the time-averaged probability distributions of non-conserved quantities like magnetization and correlation functions to the thermal distributions according to the canonical Gibbs ensemble obtained with quantum Monte Carlo simulations at temperatures defined by the excess energy in the system. We find that the occurrence of thermalization crucially depends on the quench parameters: While after the interaction quenches in the paramagnetic phase thermalization can be observed, our results for the field quenches in the ferromagnetic phase show clear deviations from the thermal system. These deviations increase with the quench strength and become especially clear comparing the shape of the thermal and the time-averaged distributions, the latter ones indicating that the system does not completely lose the memory of its initial state even for strong quenches. We discuss our results with respect to a recently formulated theorem on generalized thermalization in quantum systems.

  17. Test of quantum thermalization in the two-dimensional transverse-field Ising model

    Science.gov (United States)

    Blaß, Benjamin; Rieger, Heiko

    2016-01-01

    We study the quantum relaxation of the two-dimensional transverse-field Ising model after global quenches with a real-time variational Monte Carlo method and address the question whether this non-integrable, two-dimensional system thermalizes or not. We consider both interaction quenches in the paramagnetic phase and field quenches in the ferromagnetic phase and compare the time-averaged probability distributions of non-conserved quantities like magnetization and correlation functions to the thermal distributions according to the canonical Gibbs ensemble obtained with quantum Monte Carlo simulations at temperatures defined by the excess energy in the system. We find that the occurrence of thermalization crucially depends on the quench parameters: While after the interaction quenches in the paramagnetic phase thermalization can be observed, our results for the field quenches in the ferromagnetic phase show clear deviations from the thermal system. These deviations increase with the quench strength and become especially clear comparing the shape of the thermal and the time-averaged distributions, the latter ones indicating that the system does not completely lose the memory of its initial state even for strong quenches. We discuss our results with respect to a recently formulated theorem on generalized thermalization in quantum systems. PMID:27905523

  18. Effective field treatment of the annealed bond-dilute transverse Ising model

    International Nuclear Information System (INIS)

    Silva, P.R.; Sa Barreto, F.C. de

    1983-01-01

    The dilution of the spin-1/2 transverse Ising Model is studied by means of an effective field type treatment based on an extension of Callen's relation to the present model. The thermodynamics of the diluted model is obtained and the results are shown to be an improvement over the standard mean field treatment. The results are also compared with the Monte Carlo calculation for the spin-infinite transverse Ising Model. (Author) [pt

  19. A Comparison of Conditional Volatility Estimators for the ISE National 100 Index Returns

    OpenAIRE

    Köksal, Bülent

    2009-01-01

    We compare more than 1000 different volatility models in terms of their fit to the historical ISE-100 Index data and their forecasting performance of the conditional variance in an out-of-sample setting. Exponential GARCH model of Nelson (1991) with “constant mean, t-distribution, one lag moving average term” specification achieves the best overall performance for modeling the ISE-100 return volatility. The t-distribution seems to characterize the distribution of the heavy tailed returns bett...

  20. Visualization tool for three-dimensional plasma velocity distributions (ISEE_3D) as a plug-in for SPEDAS

    Science.gov (United States)

    Keika, Kunihiro; Miyoshi, Yoshizumi; Machida, Shinobu; Ieda, Akimasa; Seki, Kanako; Hori, Tomoaki; Miyashita, Yukinaga; Shoji, Masafumi; Shinohara, Iku; Angelopoulos, Vassilis; Lewis, Jim W.; Flores, Aaron

    2017-12-01

    This paper introduces ISEE_3D, an interactive visualization tool for three-dimensional plasma velocity distribution functions, developed by the Institute for Space-Earth Environmental Research, Nagoya University, Japan. The tool provides a variety of methods to visualize the distribution function of space plasma: scatter, volume, and isosurface modes. The tool also has a wide range of functions, such as displaying magnetic field vectors and two-dimensional slices of distributions to facilitate extensive analysis. The coordinate transformation to the magnetic field coordinates is also implemented in the tool. The source codes of the tool are written as scripts of a widely used data analysis software language, Interactive Data Language, which has been widespread in the field of space physics and solar physics. The current version of the tool can be used for data files of the plasma distribution function from the Geotail satellite mission, which are publicly accessible through the Data Archives and Transmission System of the Institute of Space and Astronautical Science (ISAS)/Japan Aerospace Exploration Agency (JAXA). The tool is also available in the Space Physics Environment Data Analysis Software to visualize plasma data from the Magnetospheric Multiscale and the Time History of Events and Macroscale Interactions during Substorms missions. The tool is planned to be applied to data from other missions, such as Arase (ERG) and Van Allen Probes after replacing or adding data loading plug-ins. This visualization tool helps scientists understand the dynamics of space plasma better, particularly in the regions where the magnetohydrodynamic approximation is not valid, for example, the Earth's inner magnetosphere, magnetopause, bow shock, and plasma sheet.

  1. Non-degenerated Ground States and Low-degenerated Excited States in the Antiferromagnetic Ising Model on Triangulations

    Science.gov (United States)

    Jiménez, Andrea

    2014-02-01

    We study the unexpected asymptotic behavior of the degeneracy of the first few energy levels in the antiferromagnetic Ising model on triangulations of closed Riemann surfaces. There are strong mathematical and physical reasons to expect that the number of ground states (i.e., degeneracy) of the antiferromagnetic Ising model on the triangulations of a fixed closed Riemann surface is exponential in the number of vertices. In the set of plane triangulations, the degeneracy equals the number of perfect matchings of the geometric duals, and thus it is exponential by a recent result of Chudnovsky and Seymour. From the physics point of view, antiferromagnetic triangulations are geometrically frustrated systems, and in such systems exponential degeneracy is predicted. We present results that contradict these predictions. We prove that for each closed Riemann surface S of positive genus, there are sequences of triangulations of S with exactly one ground state. One possible explanation of this phenomenon is that exponential degeneracy would be found in the excited states with energy close to the ground state energy. However, as our second result, we show the existence of a sequence of triangulations of a closed Riemann surface of genus 10 with exactly one ground state such that the degeneracy of each of the 1st, 2nd, 3rd and 4th excited energy levels belongs to O( n), O( n 2), O( n 3) and O( n 4), respectively.

  2. Dynamic phase transition properties for the mixed spin-(1/2, 1) Ising model in an oscillating magnetic field

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-08-15

    Herein we study the dynamic phase transition properties for the mixed spin-(1/2, 1) Ising model on a square lattice under a time-dependent magnetic field by means of the effective-field theory (EFT) with correlations based on Glauber dynamics. We present the dynamic phase diagrams in the reduced magnetic field amplitude and reduced temperature plane and find that the phase diagrams exhibit dynamic tricitical behavior, multicritical and zero-temperature critical points as well as reentrant behavior. We also investigate the influence of frequency (ω) and observe that for small values of ω the mixed phase disappears, but for high values it appears and the system displays reentrant behavior as well as a critical end point. - Highlights: • Dynamic behaviors of a ferrimagnetic mixed spin (1/2, 1) Ising system are studied. • We examined the effects of the Hamiltonian parameters on the dynamic behaviors. • The phase diagrams are obtained in (T-h) plane. • The dynamic phase diagrams exhibit the dynamic tricritical and reentrant behaviors.

  3. Dynamic phase transition properties for the mixed spin-(1/2, 1) Ising model in an oscillating magnetic field

    International Nuclear Information System (INIS)

    Ertaş, Mehmet; Keskin, Mustafa

    2015-01-01

    Herein we study the dynamic phase transition properties for the mixed spin-(1/2, 1) Ising model on a square lattice under a time-dependent magnetic field by means of the effective-field theory (EFT) with correlations based on Glauber dynamics. We present the dynamic phase diagrams in the reduced magnetic field amplitude and reduced temperature plane and find that the phase diagrams exhibit dynamic tricitical behavior, multicritical and zero-temperature critical points as well as reentrant behavior. We also investigate the influence of frequency (ω) and observe that for small values of ω the mixed phase disappears, but for high values it appears and the system displays reentrant behavior as well as a critical end point. - Highlights: • Dynamic behaviors of a ferrimagnetic mixed spin (1/2, 1) Ising system are studied. • We examined the effects of the Hamiltonian parameters on the dynamic behaviors. • The phase diagrams are obtained in (T-h) plane. • The dynamic phase diagrams exhibit the dynamic tricritical and reentrant behaviors

  4. Quantum correlated cluster mean-field theory applied to the transverse Ising model.

    Science.gov (United States)

    Zimmer, F M; Schmidt, M; Maziero, Jonas

    2016-06-01

    Mean-field theory (MFT) is one of the main available tools for analytical calculations entailed in investigations regarding many-body systems. Recently, there has been a surge of interest in ameliorating this kind of method, mainly with the aim of incorporating geometric and correlation properties of these systems. The correlated cluster MFT (CCMFT) is an improvement that succeeded quite well in doing that for classical spin systems. Nevertheless, even the CCMFT presents some deficiencies when applied to quantum systems. In this article, we address this issue by proposing the quantum CCMFT (QCCMFT), which, in contrast to its former approach, uses general quantum states in its self-consistent mean-field equations. We apply the introduced QCCMFT to the transverse Ising model in honeycomb, square, and simple cubic lattices and obtain fairly good results both for the Curie temperature of thermal phase transition and for the critical field of quantum phase transition. Actually, our results match those obtained via exact solutions, series expansions or Monte Carlo simulations.

  5. The Ising model in the scaling limit as model for the description of elementary particles

    International Nuclear Information System (INIS)

    Weinzierl, W.

    1981-01-01

    In this thesis a possible way is stepped over which starts from the derivation of a quantum field theory from simplest statistical degrees of freedom, as for instance in a two-level system. On a model theory, the Ising model in (1+1) dimensions the idea is explained. In this model theory two particle-interpretable quantum fields arise which can be constructed by a basic field which parametrizes the local dynamics in a simplest way. This so called proliferation is further examined. For the proliferation of the basic field a conserved quantity, a kind of parity is necessary. The stability of both particle fields is a consequence of this conservation law. For the identification of the ''particle-interpretable'' fields the propagators of the order and disorder parameter field are calculated and discussed. An effective Hamiltonian in this particle fields is calculated. As further aspect of this transition from the statistical system to quantum field theory the dimensional transmutation and the closely to this connected mass renormalization is examined. The relation between spin systems in the critical region and fermionic field theories is explained. Thereby it results that certain fermionic degrees of freedom of the spin system vanish in the scaling limit. The ''macroscopically'' relevant degrees of freedom constitute a relativistic Majorana field. (orig./HSI) [de

  6. Developing Information Systems for Competitive Intelligence Support.

    Science.gov (United States)

    Hohhof, Bonnie

    1994-01-01

    Discusses issues connected with developing information systems for competitive intelligence support; defines the elements of an effective competitive information system; and summarizes issues affecting system design and implementation. Highlights include intelligence information; information needs; information sources; decision making; and…

  7. IoT System Development Methods

    NARCIS (Netherlands)

    Giray, G.; Tekinerdogan, B.; Tüzün, E.

    2018-01-01

    It is generally believed that the application of methods plays an important role in developing quality systems. A development method is mainly necessary for structuring the process in producing largescale and complex systems that involve high costs. Similar to the development of other systems, it is

  8. Restructure Staff Development for Systemic Change

    Science.gov (United States)

    Kelly, Thomas F.

    2012-01-01

    This paper presents a systems approach based on the work of W. Edwards Deming to system wide, high impact staff development. Deming has pointed out the significance of structure in systems. By restructuring the process of staff development we can bring about cost effective improvement of the whole system. We can improve student achievement while…

  9. Dimensional expansion for the Ising limit of quantum field theory

    International Nuclear Information System (INIS)

    Bender, C.M.; Boettcher, S.

    1993-01-01

    A recently proposed technique, called dimensional expansion, uses the space-time dimension D as an expansion parameter to extract nonperturbative results in quantum field theory. Here we apply dimensional-expansion methods to examine the Ising limit of a self-interacting scalar field theory. We compute the first few coefficients in the dimensional expansion of γ 2n , the renormalized 2n-point Green's function at zero momentum, for n=2, 3, 4, and 5. Because the exact results for γ 2n are known at D=1 we can compare the predictions of the dimensional expansion at this value of D. We find typical accuracies of less than 5%. The radius of convergence of the dimensional expansion for γ 2n appears to be 2n/(n-1). As a function of the space-time dimension D, γ 2n appears to rise monotonically with increasing D and we conjecture that it becomes infinite at D=2n/(n-1). We presume that for values of D greater than this critical value γ 2n vanishes identically because the corresponding φ 2n scalar quantum field theory is free for D>2n/(n-1)

  10. Ising model on tangled chain - 2: Magnetization and susceptibility

    International Nuclear Information System (INIS)

    Mejdani, R.

    1993-05-01

    In the preceding paper we have considered an Ising model defined on tangled chain to study the behaviour of the free energy and entropy, particularly in the zero-field and zero-temperature limit. In this paper, following the main line and basing on some results of the previous work, we shall study in the ''language'' of state configurations the behaviour of the magnetization and the susceptibility for different conditions of the model, to understand better the competition between the ferromagnetic bonds along the chain and the antiferromagnetic additional bonds across the chain. Particularly interesting is the behaviour of the susceptibility in the zero-field and zero-temperature limit. Exact solutions for the magnetization and susceptibility, generated by analytical calculations and iterative algorithms, are described. The additional bonds, introduced as a form of perfectly disorder, indicate a particular effect on the spin correlation. We found that the condition J=-J' between the ferromagnetic interaction J along the chain and the antiferromagnetic interaction J' across the chain is somewhat as a ''transition-region'' condition for this behaviour. (author). 16 refs, 14 figs

  11. Systems of Systems: Scaling up the Development Program

    National Research Council Canada - National Science Library

    Humphrey, Watts

    2006-01-01

    ... into system-of-systems structures. Section 3 points out how large-scale systems development efforts have typically failed because of project-management and not technical problems, and that the solutions to these problems...

  12. Steady-state properties of coupled hot and cold Ising chains

    International Nuclear Information System (INIS)

    Lavrentovich, Maxim O

    2012-01-01

    Recently, the present author and Zia (2011 Europhys. Lett. 91 50003) reported on exact results for a far-from-equilibrium system in which two coupled semi-infinite Ising chains at temperatures T h and T c , with T h > T c , establish a flux of energy across their junction. This paper provides a complete derivation of those results, more explicit expressions for the energy flux, and a more detailed characterization of the system at arbitrary T c and T h . We consider the two-point correlation functions and the energy flux F(x) between each spin, located at integer position x, and its associated heat bath. In the T h → ∞ limit, the flux F(x) decays exponentially into the cold bath (spins with x = 1, 2, …) for all T c > 0 and transitions into a power-law decay as T c → 0. We find an asymptotic expansion for large x in terms of modified Bessel functions that captures both of these behaviors. We perform Monte Carlo simulations that give excellent agreement with both the exact and asymptotic results for F(x). The simulations are also used to study the system at arbitrary T h and T c . (paper)

  13. Quantum Quench Dynamics in the Transverse Field Ising Model at Non-zero Temperatures

    Science.gov (United States)

    Abeling, Nils; Kehrein, Stefan

    The recently discovered Dynamical Phase Transition denotes non-analytic behavior in the real time evolution of quantum systems in the thermodynamic limit and has been shown to occur in different systems at zero temperature [Heyl et al., Phys. Rev. Lett. 110, 135704 (2013)]. In this talk we present the extension of the analysis to non-zero temperature by studying a generalized form of the Loschmidt echo, the work distribution function, of a quantum quench in the transverse field Ising model. Although the quantitative behavior at non-zero temperatures still displays features derived from the zero temperature non-analyticities, it is shown that in this model dynamical phase transitions do not exist if T > 0 . This is a consequence of the system being initialized in a thermal state. Moreover, we elucidate how the Tasaki-Crooks-Jarzynski relation can be exploited as a symmetry relation for a global quench or to obtain the change of the equilibrium free energy density. This work was supported through CRC SFB 1073 (Project B03) of the Deutsche Forschungsgemeinschaft (DFG).

  14. Ferrimagnetism and compensation points in a decorated 3D Ising model

    International Nuclear Information System (INIS)

    Oitmaa, J.; Zheng, W.

    2003-01-01

    Full text: Ferrimagnets are materials where ions on different sublattices have opposing magnetic moments which do not exactly cancel even at zero temperature. An intriguing possibility then is the existence of a compensation point, below the Curie temperature, where the net moment changes sign. This has obvious technological significance. Most theoretical studies of such systems have used mean-field approaches, making it difficult to distinguish real properties of the model from artefacts of the approximation. For this reason a number of simpler models have been proposed, where treatments beyond mean-field theory are possible. Of particular interest are decorated systems, which can be mapped exactly onto simpler models and, in this way, either solved exactly or to a high degree of numerical precision. We use this approach to study a ferrimagnetic Ising system with spins 1/2 at the sites of a simple cubic lattice and spins S=1 or 3/2 located on the bonds. Our results, which are exact to high numerical precision, show a number of surprising and interesting features: for S=1 the possibility of zero, one or two compensation points, re-entrant behaviour, and up to three critical points; for S=3/2 always a simple critical point and zero or one compensation point

  15. Dynamic magnetizations and dynamic phase transitions in a transverse cylindrical Ising nanowire

    International Nuclear Information System (INIS)

    Deviren, Bayram; Ertaş, Mehmet; Keskin, Mustafa

    2012-01-01

    In this paper, we extend the paper of Kaneyoshi (2010 J. Magn. Magn. Mater. 322 3410-5) to investigate the dynamic magnetizations and dynamic phase transitions of a transverse cylindrical Ising nanowire system by using the effective field theory with correlations and the Glauber-type stochastic dynamics under a time-dependent oscillating external magnetic field. The dynamic effective field equations for the average longitudinal and transverse magnetizations on the surface shell and core are derived by using the Glauber transition rates. Temperature dependences of the dynamic longitudinal magnetizations, the transverse magnetizations and the total magnetizations are investigated in order to characterize the nature (first- or second-order) of the dynamic transitions as well as the dynamic phase transition temperatures and the compensation behaviors. The system is strongly affected by the surface situations. Some characteristic phenomena are found depending on the ratio of the physical parameters in the surface shell and the core. According to the values of Hamiltonian parameters, four different types of compensation behaviors in the Néel classification nomenclature exist in the system. The results are compared with some theoretical works and good overall agreement is observed. (paper)

  16. Fluctuation relations in non-equilibrium stationary states of Ising models

    Energy Technology Data Exchange (ETDEWEB)

    Piscitelli, A; Gonnella, G [Dipartimento di Fisica, Universita di Bari and Istituto Nazionale di Fisica Nucleare, Sezione di Bari, via Amendola 173, 70126 Bari (Italy); Corberi, F [Dipartimento di Matematica ed Informatica, via Ponte don Melillo, Universita di Salerno, 84084 Fisciano (Italy); Pelizzola, A [Dipartimento di Fisica and Istituto Nazionale di Fisica Nucleare, Sezione di Torino, and CNISM, Politecnico di Torino, c. Duca degli Abruzzi 24, 10129 Torino (Italy)

    2009-01-15

    Fluctuation relations for the entropy production in non-equilibrium stationary states of Ising models are investigated by means of Monte Carlo simulations. Systems in contact with heat baths at two different temperatures or subject to external driving will be studied. In the first case, considering different kinetic rules and couplings with the baths, the behaviors of the probability distributions of the heat exchanged in time {tau} with the thermostats, both in the disordered phase and in the low temperature phase, are discussed. The fluctuation relation is always followed in the large {tau} limit and deviations from linear response theory are observed. Finite {tau} corrections are shown to obey a scaling behavior. In the other case the system is in contact with a single heat bath, but work is done by shearing it. Also for this system, using the statistics collected for the mechanical work we show the validity of the fluctuation relation and the preasymptotic corrections behave analogously to those for the case with two baths.

  17. Autonomous Operations System: Development and Application

    Science.gov (United States)

    Toro Medina, Jaime A.; Wilkins, Kim N.; Walker, Mark; Stahl, Gerald M.

    2016-01-01

    Autonomous control systems provides the ability of self-governance beyond the conventional control system. As the complexity of mechanical and electrical systems increases, there develops a natural drive for developing robust control systems to manage complicated operations. By closing the bridge between conventional automated systems to knowledge based self-awareness systems, nominal control of operations can evolve into relying on safe critical mitigation processes to support any off-nominal behavior. Current research and development efforts lead by the Autonomous Propellant Loading (APL) group at NASA Kennedy Space Center aims to improve cryogenic propellant transfer operations by developing an automated control and health monitoring system. As an integrated systems, the center aims to produce an Autonomous Operations System (AOS) capable of integrating health management operations with automated control to produce a fully autonomous system.

  18. Entangled state teleportation through a couple of quantum channels composed of XXZ dimers in an Ising- XXZ diamond chain

    Science.gov (United States)

    Rojas, M.; de Souza, S. M.; Rojas, Onofre

    2017-02-01

    The quantum teleportation plays an important role in quantum information process, in this sense, the quantum entanglement properties involving an infinite chain structure is quite remarkable because real materials could be well represented by an infinite chain. We study the teleportation of an entangled state through a couple of quantum channels, composed by Heisenberg dimers in an infinite Ising-Heisenberg diamond chain, the couple of chains are considered sufficiently far away from each other to be ignored the any interaction between them. To teleporting a couple of qubits through the quantum channel, we need to find the average density operator for Heisenberg spin dimers, which will be used as quantum channels. Assuming the input state as a pure state, we can apply the concept of fidelity as a useful measurement of teleportation performance of a quantum channel. Using the standard teleportation protocol, we have derived an analytical expression for the output concurrence, fidelity, and average fidelity. We study in detail the effects of coupling parameters, external magnetic field and temperature dependence of quantum teleportation. Finally, we explore the relations between entanglement of the quantum channel, the output entanglement and the average fidelity of the system. Through a kind of phase diagram as a function of Ising-Heisenberg diamond chain model parameters, we illustrate where the quantum teleportation will succeed and a region where the quantum teleportation could fail.

  19. Quantum Criticality of an Ising-like Spin-1 /2 Antiferromagnetic Chain in a Transverse Magnetic Field

    Science.gov (United States)

    Wang, Zhe; Lorenz, T.; Gorbunov, D. I.; Cong, P. T.; Kohama, Y.; Niesen, S.; Breunig, O.; Engelmayer, J.; Herman, A.; Wu, Jianda; Kindo, K.; Wosnitza, J.; Zherlitsyn, S.; Loidl, A.

    2018-05-01

    We report on magnetization, sound-velocity, and magnetocaloric-effect measurements of the Ising-like spin-1 /2 antiferromagnetic chain system BaCo2V2O8 as a function of temperature down to 1.3 K and an applied transverse magnetic field up to 60 T. While across the Néel temperature of TN˜5 K anomalies in magnetization and sound velocity confirm the antiferromagnetic ordering transition, at the lowest temperature the field-dependent measurements reveal a sharp softening of sound velocity v (B ) and a clear minimum of temperature T (B ) at B⊥c,3 D=21.4 T , indicating the suppression of the antiferromagnetic order. At higher fields, the T (B ) curve shows a broad minimum at B⊥c=40 T , accompanied by a broad minimum in the sound velocity and a saturationlike magnetization. These features signal a quantum phase transition, which is further characterized by the divergent behavior of the Grüneisen parameter ΓB∝(B -B⊥c)-1. By contrast, around the critical field, the Grüneisen parameter converges as temperature decreases, pointing to a quantum critical point of the one-dimensional transverse-field Ising model.

  20. Study of intrinsic energy dependence of α-alanine and dose intercomparison with ESR and ISE techniques

    International Nuclear Information System (INIS)

    Laere, K. van; Bartolotta, A.; Callens, F.

    1993-01-01

    The intrinsic energy behavior of the radiation chemical yields G(R ·) and G(NH 3 ) which determine the dose response for the alanine/ESR and alanine/Ion-Selective Electrode (ISE) system, is an important characteristic for the consistent use in different radiation environments. Therefore, the response of ISS and Gent α-alanine dosimeters in the dose range 0.1 to 700 kGy was examined with 60 Co, bremsstrahlung and electron beam radiation. Bremsstrahlung beams with end point energy between 5 and 12 MeV and electron beams with mean energy at the effective point of measurement between 4 and 25 MeV were used. Analysis of the 60 Co calibration results shows that there are no significant differences in dose determination between the two laboratories. The statistical evaluation of 41 sets of independent series of measurements has shown no significant variation with beam energy. The results also confirm good consistency between ISE and ESR measurements. (author)

  1. Preparing Greenberger-Horne-Zeilinger and W states on a long-range Ising spin model by global controls

    Science.gov (United States)

    Chen, Jiahui; Zhou, Hui; Duan, Changkui; Peng, Xinhua

    2017-03-01

    Entanglement, a unique quantum resource with no classical counterpart, remains at the heart of quantum information. The Greenberger-Horne-Zeilinger (GHZ) and W states are two inequivalent classes of multipartite entangled states which cannot be transformed into each other by means of local operations and classic communication. In this paper, we present the methods to prepare the GHZ and W states via global controls on a long-range Ising spin model. For the GHZ state, general solutions are analytically obtained for an arbitrary-size spin system, while for the W state, we find a standard way to prepare the W state that is analytically illustrated in three- and four-spin systems and numerically demonstrated for larger-size systems. The number of parameters required in the numerical search increases only linearly with the size of the system.

  2. Development of similarity theory for control systems

    Science.gov (United States)

    Myshlyaev, L. P.; Evtushenko, V. F.; Ivushkin, K. A.; Makarov, G. V.

    2018-05-01

    The area of effective application of the traditional similarity theory and the need necessity of its development for systems are discussed. The main statements underlying the similarity theory of control systems are given. The conditions for the similarity of control systems and the need for similarity control control are formulated. Methods and algorithms for estimating and similarity control of control systems and the results of research of control systems based on their similarity are presented. The similarity control of systems includes the current evaluation of the degree of similarity of control systems and the development of actions controlling similarity, and the corresponding targeted change in the state of any element of control systems.

  3. Security alarm communication and display systems development

    International Nuclear Information System (INIS)

    Waddoups, I.G.

    1990-01-01

    Sandia National Laboratories (SNL) has, as lead Department of Energy (DOE) physical security laboratory, developed a variety of alarm communication and display systems for DOE and Department of Defense (DOD) facilities. This paper briefly describes some of the systems developed and concludes with a discussion of technology relevant to those currently designing, developing, implementing, or procuring such a system. Development activities and the rapid evolution of computers over the last decade have resulted in a broad variety of capabilities to support most security system communication and display needs. The major task in selecting a system is becoming familiar with these capabilities and finding the best match to a specific need

  4. Monte Carlo study of dynamic phase transition in Ising metamagnet driven by oscillating magnetic field

    International Nuclear Information System (INIS)

    Acharyya, Muktish

    2011-01-01

    The dynamical responses of Ising metamagnet (layered antiferromagnet) in the presence of a sinusoidally oscillating magnetic field are studied by Monte Carlo simulation. The time average staggered magnetisation plays the role of dynamic order parameter. A dynamical phase transition was observed and a phase diagram was plotted in the plane formed by field amplitude and temperature. The dynamical phase boundary is observed to shrink inward as the relative antiferromagnetic strength decreases. The results are compared with that obtained from pure ferromagnetic system. The shape of dynamic phase boundary observed to be qualitatively similar to that obtained from previous meanfield calculations. - Highlights: → The time average staggered magnetisation plays the role of dynamic order parameter. → A dynamical phase transition was observed and a phase diagram was plotted in the plane formed by field amplitude and temperature. → The dynamical phase boundary is observed to shrink inward as the relative antiferromagnetic strength decreases. → The results are compared with that obtained from pure ferromagnetic system. → The shape of dynamic phase boundary observed to be qualitatively similar to that obtained from previous meanfield calculation.

  5. Elementary excitations and the phase transition in the bimodal Ising spin glass model

    International Nuclear Information System (INIS)

    Jinuntuya, N; Poulter, J

    2012-01-01

    We show how the nature of the phase transition in the two-dimensional bimodal Ising spin glass model can be understood in terms of elementary excitations. Although the energy gap with the ground state is expected to be 4J in the ferromagnetic phase, a gap 2J is in fact found if the finite lattice is wound around a cylinder of odd circumference L. This 2J gap is really a finite size effect that should not occur in the thermodynamic limit of the ferromagnet. The spatial influence of the frustration must be limited and not wrap around the system if L is large enough. In essence, the absence of 2J excitations defines the ferromagnetic phase without recourse to calculating the magnetization or investigating the system response to domain wall defects. This study directly investigates the response to temperature. We also estimate the defect concentration where the phase transition to the spin glass state occurs. The value p c = 0.1045(11) is in reasonable agreement with the literature

  6. Development of Baby-EBM Interface System

    International Nuclear Information System (INIS)

    Mukhlis Mokhtar; Abu Bakar Ghazali; Muhammad Zahidee Taat

    2010-01-01

    This paper explains the works being done to develop an interface system for Baby-Electron Beam Machine (EBM). The function of the system is for the safety, controlling and monitoring the Baby-EBM. The integration for the system is using data acquisition (DAQ) hardware and LabVIEW to develop the software. (author)

  7. Development of Baby-EBM Interface System

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtar, Mukhlis; Ghazali, Abu Bakar; Taat, Muhammad Zahidee [Accelerator Development Center, Malaysian Nuclear Agency, Bangi, Kajang, Selangor (Malaysia), Technical Support Div.

    2010-07-01

    This paper explains the works being done to develop an interface system for Baby-Electron Beam Machine (EBM). The function of the system is for the safety, controlling and monitoring the Baby-EBM. The integration for the system is using data acquisition (DAQ) hardware and LabVIEW to develop the software. (author)

  8. Holonomic functions of several complex variables and singularities of anisotropic Ising n-fold integrals

    Science.gov (United States)

    Boukraa, S.; Hassani, S.; Maillard, J.-M.

    2012-12-01

    Focusing on examples associated with holonomic functions, we try to bring new ideas on how to look at phase transitions, for which the critical manifolds are not points but curves depending on a spectral variable, or even fill higher dimensional submanifolds. Lattice statistical mechanics often provides a natural (holonomic) framework to perform singularity analysis with several complex variables that would, in the most general mathematical framework, be too complex, or simply could not be defined. In a learn-by-example approach, considering several Picard-Fuchs systems of two-variables ‘above’ Calabi-Yau ODEs, associated with double hypergeometric series, we show that D-finite (holonomic) functions are actually a good framework for finding properly the singular manifolds. The singular manifolds are found to be genus-zero curves. We then analyze the singular algebraic varieties of quite important holonomic functions of lattice statistical mechanics, the n-fold integrals χ(n), corresponding to the n-particle decomposition of the magnetic susceptibility of the anisotropic square Ising model. In this anisotropic case, we revisit a set of so-called Nickelian singularities that turns out to be a two-parameter family of elliptic curves. We then find the first set of non-Nickelian singularities for χ(3) and χ(4), that also turns out to be rational or elliptic curves. We underline the fact that these singular curves depend on the anisotropy of the Ising model, or, equivalently, that they depend on the spectral parameter of the model. This has important consequences on the physical nature of the anisotropic χ(n)s which appear to be highly composite objects. We address, from a birational viewpoint, the emergence of families of elliptic curves, and that of Calabi-Yau manifolds on such problems. We also address the question of singularities of non-holonomic functions with a discussion on the accumulation of these singular curves for the non-holonomic anisotropic full

  9. Holonomic functions of several complex variables and singularities of anisotropic Ising n-fold integrals

    International Nuclear Information System (INIS)

    Boukraa, S; Hassani, S; Maillard, J-M

    2012-01-01

    Focusing on examples associated with holonomic functions, we try to bring new ideas on how to look at phase transitions, for which the critical manifolds are not points but curves depending on a spectral variable, or even fill higher dimensional submanifolds. Lattice statistical mechanics often provides a natural (holonomic) framework to perform singularity analysis with several complex variables that would, in the most general mathematical framework, be too complex, or simply could not be defined. In a learn-by-example approach, considering several Picard–Fuchs systems of two-variables ‘above’ Calabi–Yau ODEs, associated with double hypergeometric series, we show that D-finite (holonomic) functions are actually a good framework for finding properly the singular manifolds. The singular manifolds are found to be genus-zero curves. We then analyze the singular algebraic varieties of quite important holonomic functions of lattice statistical mechanics, the n-fold integrals χ (n) , corresponding to the n-particle decomposition of the magnetic susceptibility of the anisotropic square Ising model. In this anisotropic case, we revisit a set of so-called Nickelian singularities that turns out to be a two-parameter family of elliptic curves. We then find the first set of non-Nickelian singularities for χ (3) and χ (4) , that also turns out to be rational or elliptic curves. We underline the fact that these singular curves depend on the anisotropy of the Ising model, or, equivalently, that they depend on the spectral parameter of the model. This has important consequences on the physical nature of the anisotropic χ (n) s which appear to be highly composite objects. We address, from a birational viewpoint, the emergence of families of elliptic curves, and that of Calabi–Yau manifolds on such problems. We also address the question of singularities of non-holonomic functions with a discussion on the accumulation of these singular curves for the non

  10. INNOVATIVE DEVELOPMENT OF EDUCATIONAL SYSTEMS: CATEGORICAL MEANING

    Directory of Open Access Journals (Sweden)

    Natalia Tretyak

    2017-06-01

    Full Text Available This article discusses the concept of «development», «innovation» and «innovation development» in relation to the educational systems, as to create a new conceptual framework for quality education. Peculiarities of development of educational systems. Correlation concepts «organization development» and «innovation», defined birth of innovation as syncope in music. On the basis of the study given to the notion of innovation development of educational systems and identified conditions for their successful innovation development.

  11. Canadian accelerator breeder system development

    International Nuclear Information System (INIS)

    Schriber, S.O.

    1982-11-01

    A shortage of fissile material at a reasonable price is expected to occur in the early part of the twenty-first century. Converting fertile material to fissile material by electronuclar methods is an option that can extend th world's resources of fissionable material, supplying fuel for nuclear power stations. This paper presents the rationale for electronuclear breeders and describes the Canadian development program for an accelerator breeder facility that could produce 1 Mg of fissile material per year

  12. The spin-3/2 Ising model AFM/AFM two-layer lattice with crystal field

    International Nuclear Information System (INIS)

    Yigit, A.; Albayrak, E.

    2010-01-01

    The spin-3/2 Ising model is investigated for the case of antiferromagnetic (AFM/AFM) interactions on the two-layer Bethe lattice by using the exact recursion relations in a pairwise approach for given coordination numbers q=3, 4 and 6 when the layers are under the influences of equal external magnetic and equal crystal fields. The ground state (GS) phase diagrams are obtained on the different planes in detail and then the temperature dependent phase diagrams of the system are calculated accordingly. It is observed that the system presents both second- and first-order phase transitions for all q, therefore, tricritical points. It was also found that the system exhibits double-critical end points and isolated points. The model also presents two Neel temperatures, TN, and the existence of which leads to the reentrant behavior.

  13. Senior Systems Analyst | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... Systems Analyst will play a critical role as part of the Information Technology ... data analysis, and system design); the delivery of professional IM/IT advisory and ... with the current development activities ensuring resolution of those issues.

  14. Development of geophysical data management system

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Tai-Sup; Lee, Sang-Kyu; Gu, Sung-Bon [Korea Institute of Geology Mining and Materials, Taejon (KR)] (and others)

    1999-12-01

    (1) Development of a complete geophysical database system under C/S environment for data management. (2) Development of database system for the general user, who has not special knowledge of database, under the Internet environment. (3) Operation of the Web service for the general user. (4) Development of the stand-alone database system for a small-scale research group such as college and engineering consultant firms. (author). 15 refs.

  15. Model Driven Development of Data Sensitive Systems

    DEFF Research Database (Denmark)

    Olsen, Petur

    2014-01-01

    storage systems, where the actual values of the data is not relevant for the behavior of the system. For many systems the values are important. For instance the control flow of the system can be dependent on the input values. We call this type of system data sensitive, as the execution is sensitive...... to the values of variables. This theses strives to improve model-driven development of such data-sensitive systems. This is done by addressing three research questions. In the first we combine state-based modeling and abstract interpretation, in order to ease modeling of data-sensitive systems, while allowing...... efficient model-checking and model-based testing. In the second we develop automatic abstraction learning used together with model learning, in order to allow fully automatic learning of data-sensitive systems to allow learning of larger systems. In the third we develop an approach for modeling and model-based...

  16. Aviation Information Systems Development Laboratory (AISDL)

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose:The Aviation Information Systems Development Laboratory (AISDL) provides the tools, reconfigurability and support to ensure the quality and integrity of new...

  17. Development of the heavy manipulator vehicle system

    International Nuclear Information System (INIS)

    Herbst, C.; Paustian, P.; Kruger, W.

    1993-01-01

    After the severe reactor accident of Tschernobyl in 1986 MaK System started to develop a Heavy Manipulator Vehicle System under contract from German nuclear technology assistance company ''KHG'' (Kerntechnische Hilfsdienst GmbH). The system comprises a remote controlled manipulator vehicle, a mobile mission control stand as well as a transport/service unit. In order to fulfill the high demands of this complex system a couple of new developments had to be started. The paper describes some of these developments and gives an overview about the main features of the Heavy Manipulator Vehicle System (HMV). (author)

  18. Emergent Ising degrees of freedom above a double-stripe magnetic ground state

    Science.gov (United States)

    Zhang, Guanghua; Flint, Rebecca

    2017-12-01

    Double-stripe magnetism [Q =(π /2 ,π /2 )] has been proposed as the magnetic ground state for both the iron-telluride and BaTi2Sb2O families of superconductors. Double-stripe order is captured within a J1-J2-J3 Heisenberg model in the regime J3≫J2≫J1 . Intriguingly, besides breaking spin-rotational symmetry, the ground-state manifold has three additional Ising degrees of freedom associated with bond ordering. Via their coupling to the lattice, they give rise to an orthorhombic distortion and to two nonuniform lattice distortions with wave vector (π ,π ) . Because the ground state is fourfold degenerate, modulo rotations in spin space, only two of these Ising bond order parameters are independent. Here, we introduce an effective field theory to treat all Ising order parameters, as well as magnetic order, and solve it within a large-N limit. All three transitions, corresponding to the condensations of two Ising bond order parameters and one magnetic order parameter are simultaneous and first order in three dimensions, but lower dimensionality, or equivalently weaker interlayer coupling, and weaker magnetoelastic coupling can split the three transitions, and in some cases allows for two separate Ising phase transitions above the magnetic one.

  19. Kinetic Ising model in a time-dependent oscillating external magnetic field: effective-field theory

    International Nuclear Information System (INIS)

    Deviren, Bayram; Canko, Osman; Keskin, Mustafa

    2010-01-01

    Recently, Shi et al. [2008 Phys. Lett. A 372 5922] have studied the dynamical response of the kinetic Ising model in the presence of a sinusoidal oscillating field and presented the dynamic phase diagrams by using an effective-field theory (EFT) and a mean-field theory (MFT). The MFT results are in conflict with those of the earlier work of Tomé and de Oliveira, [1990 Phys. Rev. A 41 4251]. We calculate the dynamic phase diagrams and find that our results are similar to those of the earlier work of Tomé and de Oliveira; hence the dynamic phase diagrams calculated by Shi et al. are incomplete within both theories, except the low values of frequencies for the MFT calculation. We also investigate the influence of external field frequency (ω) and static external field amplitude (h 0 ) for both MFT and EFT calculations. We find that the behaviour of the system strongly depends on the values of ω and h 0 . (general)

  20. Effective field approach to the Ising film in a transverse field

    International Nuclear Information System (INIS)

    Peliti, L.; Saber, M.

    1998-05-01

    Within the framework of the effective field theory, we examine the phase transitions of the spin -1/2 Ising film in a transverse field. We study the critical temperature of the film as a function of the exchange interactions, the transverse field and the film thickness. We find that, if the ratio of the surface exchange interactions to the bulk ones R=J s /J is smaller that a critical value R c , the critical temperature T c /J of the film is smaller that the bulk critical temperature T B c /J and as R is increased further, T c /J approaches T B c /J. On the other hand, if R>R c ,T c /J is larger than the bulk T B c /J and the surface T S c /J critical temperatures of the corresponding semi-infinite system and as R is increased further, T c /J approaches the surface critical temperature T S c /J. (author)

  1. Development of JT-60 diagnostics system

    International Nuclear Information System (INIS)

    Suzuki, Yasuo

    1988-01-01

    The various kinds of plasma diagnostics have been developed and utilized in the JT-60 experiments. The features of JT-60 diagnostics system and the historical proceeding of the development are described in this paper. Taking account of the design consideration, JT-60 diagnostics system is sorted out into eight groups, which include six diagnostics systems, the data processing system and diagnostics supporting system. The all devices in the JT-60 diagnostics system were instrumented on schedule in the end of the fiscal year of 1985 and have contributed to JT-60 experiments. (author)

  2. Global control methods for Greenberger-Horne-Zeilinger-state generation on a one-dimensional Ising chain

    International Nuclear Information System (INIS)

    Wang Xiaoting; Schirmer, Sophie G.; Bayat, Abolfazl; Bose, Sougato

    2010-01-01

    We discuss how to prepare an Ising chain in a GHZ state using a single global control field only. This model does not require the spins to be individually addressable and is applicable to quantum systems such as cold atoms in optical lattices, some liquid- or solid-state NMR experiments, and many nanoscale quantum structures. We show that GHZ states can always be reached asymptotically from certain easy-to-prepare initial states using adiabatic passage, and under certain conditions finite-time reachability can be ensured. To provide a reference useful for future experimental implementations, three different control strategies to achieve the objective--adiabatic passage, Lyapunov control, and optimal control--are compared, and their advantages and disadvantages discussed, in particular in the presence of realistic imperfections such as imperfect initial state preparation, system inhomogeneity, and dephasing.

  3. The quantum transverse spin-2 Ising model with a bimodal random-field in the pair approximation

    International Nuclear Information System (INIS)

    Canko, O.; Albayrak, E.; Keskin, M.

    2005-01-01

    In this paper, we have investigated the bimodal random-field spin-2 Ising system in a transverse field by combining the pair approximation with the discretized path-integral representation. The exact equations for the second-order phase transition lines and tricritical points are obtained in terms of the random field H, the transverse field G and the coordination number z. It is found that there are some critical values for H and G where the tricritical points disappear for given z. We have also observed that the system presents reentrant behavior which may be caused by the quantum effects and randomness. The phase diagram with respect to the random field and the second-order phase transition temperature are studied extensively for given values of the transverse field and the coordination number

  4. Dynamic phase diagrams of the Ising metamagnet in an oscillating magnetic field within the effective-field theory

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-12

    Dynamic aspects of a two-sublattice Ising metamagnet on honeycomb, square and hexagonal lattices under the presence of a time-dependent oscillating external magnetic field are studied by using the effective-field theory with correlations. The set of effective-field dynamic equations is derived by employing Glauber transition rates. The phases in the system are obtained by solving these dynamic equations. The thermal behavior of the dynamic staggered 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. The phase diagrams are constructed in two different planes, and exhibit dynamic tricritical behavior, which strongly depends on interaction parameters. In order to investigate the spin correlation effect on the dynamic phase diagrams of the system, the results are also given within the framework of the dynamic mean-field approximation.

  5. Dynamic phase diagrams of the Ising metamagnet in an oscillating magnetic field within the effective-field theory

    International Nuclear Information System (INIS)

    Deviren, Bayram; Keskin, Mustafa

    2010-01-01

    Dynamic aspects of a two-sublattice Ising metamagnet on honeycomb, square and hexagonal lattices under the presence of a time-dependent oscillating external magnetic field are studied by using the effective-field theory with correlations. The set of effective-field dynamic equations is derived by employing Glauber transition rates. The phases in the system are obtained by solving these dynamic equations. The thermal behavior of the dynamic staggered 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. The phase diagrams are constructed in two different planes, and exhibit dynamic tricritical behavior, which strongly depends on interaction parameters. In order to investigate the spin correlation effect on the dynamic phase diagrams of the system, the results are also given within the framework of the dynamic mean-field approximation.

  6. Notes on innovation systems and economic development

    DEFF Research Database (Denmark)

    Lundvall, Bengt-Åke

    2011-01-01

    This paper gives a brief history and background for the concept 'national innovation system' and discusses its usefulness for understanding and managing economic development.......This paper gives a brief history and background for the concept 'national innovation system' and discusses its usefulness for understanding and managing economic development....

  7. Development of a School Leadership Evaluation System

    Science.gov (United States)

    Orlando, Nik

    2014-01-01

    This action research study examined the effectiveness of the process implemented by Partnerships to Uplift Communities (PUC) Schools Charter Management Organization to develop their school leader evaluation system in collaboration with current PUC school leaders. The development of the leadership evaluation system included the collective voices of…

  8. ISEE observations of radiation at twice the solar wind plasma frequency

    International Nuclear Information System (INIS)

    Lacombe, C.; Harvey, C.C.; Hoang, S.

    1988-01-01

    Radiation produced in the vicinity of the Earth's bow shock at twice the solar wind electron plasma frequency f p is seen by both ISEE-1 and ISEE-3, respectively at about 20 and about 200 R E from the Earth. This electromagnetic radiation is due to the presence, in the electron foreshock, of electrons reflected and accelerated at the Earth's bow shock. We show that the source is near the upstream boundary of the foreshock, the surface where the magnetic field lines are tangent to the bow shock. A typical diameter of the source is 120-150 R E . Emissivity is given. The angular size of the source, seen by ISEE-3, is increased by scattering of the 2f p radio waves on the solar wind density fluctuations. We examine whether the bandwidth and directivity predicted by current source models are consistent with our observations

  9. Triangular and honeycomb lattices bond-diluted Ising ferromagnet: critical frontier

    International Nuclear Information System (INIS)

    Magalhaes, A.C.N. de; Schwaccheim, G.; Tsallis, C.

    1982-01-01

    Within a real space renormalization group framework (12 different procedures, all of them using star-triangle and duality-type transformations) accurate approximations for the critical frontiers associated with the quenched bond-diluted first-neighbour spin- 1 / 2 Ising ferromagnet on triangular and honeycomb lattices are calculated. All of them provide, in both pure bond percolation and pure Ising limits, the exact critical points and exact or almost exact derivatives in the p-t space (p is the bond independent occupancy probability and t tanh J/k(sub B)T). The best numerical proposals lead to the exact derivative in the pure percolation limit (p = p(sub c)) and, in what concerns the pure Ising limit (p = 1) derivative, to a 0.15% error for the triangular lattice and to a 0.96% error for the honeycomb one; in the intermediate region (p(sub c) [pt

  10. Long-range transverse Ising model built with dipolar condensates in two-well arrays

    International Nuclear Information System (INIS)

    Li, Yongyao; Pang, Wei; Xu, Jun; Lee, Chaohong; Malomed, Boris A; Santos, Luis

    2017-01-01

    Dipolar Bose–Einstein condensates in an array of double-well potentials realize an effective transverse Ising model with peculiar inter-layer interactions, that may result under proper conditions in an anomalous first-order ferromagnetic–antiferromagnetic phase transition, and non-trivial phases due to frustration. The considered setup allows as well for the study of Kibble–Zurek defect formation, whose kink statistics follows that expected from the universality class of the mean-field one-dimensional transverse Ising model. Furthermore, random occupation of each layer of the stack leads to random effective Ising interactions and local transverse fields, that may lead to the Anderson-like localization of imbalance perturbations. (paper)

  11. Automotive mechatronic systems. General developments and examples

    Energy Technology Data Exchange (ETDEWEB)

    Isermann, R. [Technische Univ. Darmstadt (Germany). Inst. fuer Automatisierungstechnik, FG Regelungstechnik und Prozessautomatisierung

    2006-08-15

    Automobiles are showing an increasing integration of mechanics with digital electronics and information processing. This integration is between the components (hardware) and by the information-driven functions (software), resulting in integrated systems called mechatronic systems. Their development involves finding an optimal balance between the basic mechanical structure, sensor and actuator implementation, communication, automatic information processing and overall control. This contribution summarizes some ongoing developments for mechatronic systems in automobiles, shows design approaches and examples and considers the various embedded control functions and systems integrity. Some examples of automotive mechatronic systems are shown in more detail. Great progress can be observed in braking systems (ABS, ESP), the first brake-by-wire electro-hydraulic brake system (EHB), steering systems (electrical power steering, active front steering) and active suspension systems. (orig.)

  12. Development of sorting system control using LABVIEW

    International Nuclear Information System (INIS)

    Azraf Azman; Mohd Arif Hamzah; Noriah Mod Ali; John Konsoh; Mohd Idris Taib; Maslina Mohd Ibrahim; Nor Arymaswati Abdullah; Abu Bakar Mhd Ghazali

    2005-01-01

    The development of the Personnel Dosimeter Sorting System, proposed by the Secondary Standard Dosimetry Laboratory (SSDL) is to enhance the system or work flow in preparing the personnel dosimeter. The main objective of the system is to reduce stamping error, time and cost. The Personnel Dosimeter Sorting System is a semi-automatic system with an interfacing method using the Advantec 32 bit PCI interface card of 64 digital input and output. The system is integrated with the Labview version 7.1 programming language to control the sorting system and operation. (Author)

  13. Development of Residential SOFC Cogeneration System

    Science.gov (United States)

    Ono, Takashi; Miyachi, Itaru; Suzuki, Minoru; Higaki, Katsuki

    2011-06-01

    Since 2001 Kyocera has been developing 1kW class Solid Oxide Fuel Cell (SOFC) for power generation system. We have developed a cell, stack, module and system. Since 2004, Kyocera and Osaka Gas Co., Ltd. have been developed SOFC residential co-generation system. From 2007, we took part in the "Demonstrative Research on Solid Oxide Fuel Cells" Project conducted by New Energy Foundation (NEF). Total 57 units of 0.7kW class SOFC cogeneration systems had been installed at residential houses. In spite of residential small power demand, the actual electric efficiency was about 40%(netAC,LHV), and high CO2 reduction performance was achieved by these systems. Hereafter, new joint development, Osaka Gas, Toyota Motors, Kyocera and Aisin Seiki, aims early commercialization of residential SOFC CHP system.

  14. Testing Infrastructure for Operating System Kernel Development

    DEFF Research Database (Denmark)

    Walter, Maxwell; Karlsson, Sven

    2014-01-01

    Testing is an important part of system development, and to test effectively we require knowledge of the internal state of the system under test. Testing an operating system kernel is a challenge as it is the operating system that typically provides access to this internal state information. Multi......-core kernels pose an even greater challenge due to concurrency and their shared kernel state. In this paper, we present a testing framework that addresses these challenges by running the operating system in a virtual machine, and using virtual machine introspection to both communicate with the kernel...... and obtain information about the system. We have also developed an in-kernel testing API that we can use to develop a suite of unit tests in the kernel. We are using our framework for for the development of our own multi-core research kernel....

  15. Development of Residential SOFC Cogeneration System

    International Nuclear Information System (INIS)

    Ono, Takashi; Miyachi, Itaru; Suzuki, Minoru; Higaki, Katsuki

    2011-01-01

    Since 2001 Kyocera has been developing 1kW class Solid Oxide Fuel Cell (SOFC) for power generation system. We have developed a cell, stack, module and system. Since 2004, Kyocera and Osaka Gas Co., Ltd. have been developed SOFC residential co-generation system. From 2007, we took part in the 'Demonstrative Research on Solid Oxide Fuel Cells' Project conducted by New Energy Foundation (NEF). Total 57 units of 0.7kW class SOFC cogeneration systems had been installed at residential houses. In spite of residential small power demand, the actual electric efficiency was about 40%(netAC,LHV), and high CO2 reduction performance was achieved by these systems. Hereafter, new joint development, Osaka Gas, Toyota Motors, Kyocera and Aisin Seiki, aims early commercialization of residential SOFC CHP system.

  16. Development of a new national innovation system

    Directory of Open Access Journals (Sweden)

    Domazet Dragan S.

    2003-01-01

    Full Text Available The paper describes a reference model of the national innovation system of Serbia planned to be gradually developed. The model presented is not complete, but is sufficient to illustrate its usage. The development of a national innovation system may be achieved by implementing a phased and segmented approach. This means that parts of the innovation system that are related to specific industrial sectors may be developed separately according to national priorities. Also, the system may be improved and expanded in later phases of its development. The approach suggested is demonstrated in the case of the innovation system of the software industry. The necessary programs and measures for supporting the development of the software industry are listed. Once these programs and measures are implemented, the software industry in Serbia may be able to reach global competitiveness.

  17. Toward the Development of Expert Assessment Systems.

    Science.gov (United States)

    Hasselbring, Ted S.

    1986-01-01

    The potential application of "expert systems" to the diagnosis and assessment of special-needs children is examined and existing prototype systems are reviewed. The future of this artificial intelligence technology is discussed in relation to emerging development tools designed for the creation of expert systems by the lay public. (Author)

  18. [Development of operation patient security detection system].

    Science.gov (United States)

    Geng, Shu-Qin; Tao, Ren-Hai; Zhao, Chao; Wei, Qun

    2008-11-01

    This paper describes a patient security detection system developed with two dimensional bar codes, wireless communication and removal storage technique. Based on the system, nurses and correlative personnel check code wait operation patient to prevent the defaults. The tests show the system is effective. Its objectivity and currency are more scientific and sophisticated than current traditional method in domestic hospital.

  19. Hera : Development of semantic web information systems

    NARCIS (Netherlands)

    Houben, G.J.P.M.; Barna, P.; Frasincar, F.; Vdovják, R.; Cuella Lovelle, J.M.; et al., xx

    2003-01-01

    As a consequence of the success of the Web, methodologies for information system development need to consider systems that use the Web paradigm. These Web Information Systems (WIS) use Web technologies to retrieve information from the Web and to deliver information in a Web presentation to the

  20. Development of steering system in network environment

    International Nuclear Information System (INIS)

    Kanagawa, Fumihiro; Noguchi, So; Yamashita, Hideo

    2002-01-01

    We have been developing the steering system, which can successively observe the-data obtained during the numerical computation and change the parameters in the analysis. Moreover, this system is also extended to link the network. By using this system, a user can easily detect errors immediately and achieve the rapid and accurate analysis with lower computation cost. (Author)

  1. Development of the affiliate system based on modern development methodologies

    OpenAIRE

    Fajmut, Aljaž

    2016-01-01

    Affiliate partnership is a popular and effective method of online marketing through affiliate partners. The thesis describes the development of a product, which allows us to easily integrate affiliate system into an existing platform (e-commerce or service). This kind of functionality opens up growth opportunities for the business. The system is designed in a way that it requires minimal amount of changes for the implementation into an existing application. The development of the product is ...

  2. Ecosocial System: Structure, Development Laws and Functioning

    Directory of Open Access Journals (Sweden)

    E. I. Alekseev

    2004-01-01

    Full Text Available The paper substantiates necessity to develop a unified system of socio-ecological knowledge. Ecosophy being a forming component of dialectic-materialistic philosophy has been proposed as such system. Structure, development laws and functioning of eco-social system are considered as a part of ecosophy theory. Standard laws and ecological principles being widely recognized by ecologically orientated theorists are stated in the paper.

  3. An Integrated Glucose Sensor with an All-Solid-State Sodium Ion-Selective Electrode for a Minimally Invasive Glucose Monitoring System

    Directory of Open Access Journals (Sweden)

    Junko Kojima

    2015-06-01

    Full Text Available We developed a minimally invasive glucose monitoring system that uses a microneedle to permeate the skin surface and a small hydrogel to accumulate interstitial fluid glucose. The measurement of glucose and sodium ion levels in the hydrogel is required for estimating glucose levels in blood; therefore, we developed a small, enzyme-fixed glucose sensor with a high-selectivity, all-solid-state, sodium ion-selective electrode (ISE integrated into its design. The glucose sensor immobilized glucose oxidase showed a good correlation between the glucose levels in the hydrogels and the reference glucose levels (r > 0.99, and exhibited a good precision (coefficient of variation = 2.9%, 0.6 mg/dL. In the design of the sodium ISEs, we used the insertion material Na0.33MnO2 as the inner contact layer and DD16C5 exhibiting high Na+/K+ selectivity as the ionophore. The developed sodium ISE exhibited high selectivity (\\( \\log \\,k^{pot}_{Na,K} = -2.8\\ and good potential stability. The sodium ISE could measure 0.4 mM (10−3.4 M sodium ion levels in the hydrogels containing 268 mM (10−0.57 M KCl. The small integrated sensor (ϕ < 10 mm detected glucose and sodium ions in hydrogels simultaneously within 1 min, and it exhibited sufficient performance for use as a minimally invasive glucose monitoring system.

  4. Cross functional organisational embedded system development

    OpenAIRE

    Lennon, Sophie

    2015-01-01

    peer-reviewed Embedded system development is continuing to grow. Medical, automotive and Internet of Things are just some of the market segments. There is a tight coupling between hardware and software when developing an embedded system, often needing to meet strict performance targets, standards requirements and aggressive schedules. Embedded software developers need to consider hardware requirements in far greater detail as they can have a significant impact on the quality and value of t...

  5. Developing Sustainable Life Support System Concepts

    Science.gov (United States)

    Thomas, Evan A.

    2010-01-01

    Sustainable spacecraft life support concepts may allow the development of more reliable technologies for long duration space missions. Currently, life support technologies at different levels of development are not well evaluated against each other, and evaluation methods do not account for long term reliability and sustainability of the hardware. This paper presents point-of-departure sustainability evaluation criteria for life support systems, that may allow more robust technology development, testing and comparison. An example sustainable water recovery system concept is presented.

  6. Tribes of Users and System Developers

    Directory of Open Access Journals (Sweden)

    Sharon Dingley

    2000-05-01

    Full Text Available Effective communication is essential for information systems development crossing functional, organisational and national boundaries. As organisations attempt to overcome cultural barriers to communication across the world, communication with colleagues across the corridor remains problematic; cultural barriers between departments remain unchallenged. This paper introduces the concepts of 'culture' and 'tribe' into the discussion of the relationship between business users and information systems developers. Previous research has focused on identifying specific barriers to user-systems developer communication and on ways of eliminating these barriers. In contrast, this paper suggests that much can be learnt through the recognition of cultural differences inherent to the differing roles of user and systems developer. Maintenance of cultural identity is essential to the individual if he/she is to function effectively as a member of his/her tribe, whether it is the 'tribe' of developers or the 'tribe' of users. Communication problems within the systems development process may be addressed by a mutual understanding of cultural differences between the 'tribes' of users and systems developers. This degree of understanding cannot be achieved by attempting to change, persuade or convert the other tribe. The problems of user-systems developer communication need to be addressed through effective communication which acknowledges the differing cultures.

  7. Social networks and mortality based on the Komo-Ise cohort study in Japan.

    Science.gov (United States)

    Iwasaki, Motoki; Otani, Tetsuya; Sunaga, Rumiko; Miyazaki, Hiroko; Xiao, Liu; Wang, Naren; Yosiaki, Sasazawa; Suzuki, Shosuke

    2002-12-01

    No prospective studies have examined the association between social networks and all-cause and cause-specific mortality among middle-aged Japanese. The study of varied populations may contribute to clarifying the robustness of the observed effects of social networks and extend their generalizability. To clarify the association between social networks and mortality among middle-aged and elderly Japanese, a community-based prospective study, the Komo-Ise Study, was conducted in two areas of Gunma Prefecture, Japan. A total of 11 565 subjects aged 40-69 years at baseline in 1993 completed a self-administered questionnaire. During the 7-year follow-up period, 335 men and 155 women died and the relative risk (RR) of each social network item was estimated by the Cox proportional hazard model. Single women had significantly increased risks of all-cause (multivariate RR = 2.2), and all circulatory system disease (age-area adjusted RR = 2.6) mortality. Men who did not participate in hobbies, club activities, or community groups had significantly higher multivariate RR for all-cause (RR = 1.5), all circulatory system disease (RR = 1.6) and non-cancer and non-circulatory system disease (RR = 2.3) mortality. Urban women who rarely or never met close relatives had significantly elevated risks of all-cause (RR = 2.4), all cancer (RR = 2.6), and non-cancer and non-circulatory system disease (RR = 2.7) mortality after adjustment for established risk factors. This study provides evidence that social networks are an important predictor of mortality risk for middle-aged and elderly Japanese men and women. Lack of participation, for men, and being single and lack of meeting close relatives, for women, were independent risk factors for mortality.

  8. Multi spin-flip dynamics: a solution of the one-dimensional Ising model

    International Nuclear Information System (INIS)

    Novak, I.

    1990-01-01

    The Glauber dynamics of interacting Ising spins (the single spin-flip dynamics) is generalized to p spin-flip dynamics with a simultaneous flip of up to p spins in a single configuration move. The p spin-flip dynamics is studied of the one-dimensional Ising model with uniform nearest-neighbour interaction. For this case, an exact relation is given for the time dependence of magnetization. It was found that the critical slowing down in this model could be avoided when p spin-flip dynamics with p>2 was considered. (author). 17 refs

  9. Probabilistic image processing by means of the Bethe approximation for the Q-Ising model

    International Nuclear Information System (INIS)

    Tanaka, Kazuyuki; Inoue, Jun-ichi; Titterington, D M

    2003-01-01

    The framework of Bayesian image restoration for multi-valued images by means of the Q-Ising model with nearest-neighbour interactions is presented. Hyperparameters in the probabilistic model are determined so as to maximize the marginal likelihood. A practical algorithm is described for multi-valued image restoration based on the Bethe approximation. The algorithm corresponds to loopy belief propagation in artificial intelligence. We conclude that, in real world grey-level images, the Q-Ising model can give us good results

  10. Canonical vs. micro-canonical sampling methods in a 2D Ising model

    International Nuclear Information System (INIS)

    Kepner, J.

    1990-12-01

    Canonical and micro-canonical Monte Carlo algorithms were implemented on a 2D Ising model. Expressions for the internal energy, U, inverse temperature, Z, and specific heat, C, are given. These quantities were calculated over a range of temperature, lattice sizes, and time steps. Both algorithms accurately simulate the Ising model. To obtain greater than three decimal accuracy from the micro-canonical method requires that the more complicated expression for Z be used. The overall difference between the algorithms is small. The physics of the problem under study should be the deciding factor in determining which algorithm to use. 13 refs., 6 figs., 2 tabs

  11. Phase transitions in the random field Ising model in the presence of a transverse field

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, A.; Chakrabarti, B.K. [Saha Institute of Nuclear Physics, Bidhannagar, Calcutta (India); Stinchcombe, R.B. [Saha Institute of Nuclear Physics, Bidhannagar, Calcutta (India); Department of Physics, Oxford (United Kingdom)

    1996-09-07

    We have studied the phase transition behaviour of the random field Ising model in the presence of a transverse (or tunnelling) field. The mean field phase diagram has been studied in detail, and in particular the nature of the transition induced by the tunnelling (transverse) field at zero temperature. Modified hyper-scaling relation for the zero-temperature transition has been derived using the Suzuki-Trotter formalism and a modified 'Harris criterion'. Mapping of the model to a randomly diluted antiferromagnetic Ising model in uniform longitudinal and transverse field is also given. (author)

  12. Ground-state candidate for the classical dipolar kagome Ising antiferromagnet

    Science.gov (United States)

    Chioar, I. A.; Rougemaille, N.; Canals, B.

    2016-06-01

    We have investigated the low-temperature thermodynamic properties of the classical dipolar kagome Ising antiferromagnet using Monte Carlo simulations, in the quest for the ground-state manifold. In spite of the limitations of a single-spin-flip approach, we managed to identify certain ordering patterns in the low-temperature regime and we propose a candidate for this unknown state. This configuration presents some intriguing features and is fully compatible with the extrapolations of the at-equilibrium thermodynamic behavior sampled so far, making it a very likely choice for the dipolar long-range ordered state of the classical kagome Ising antiferromagnet.

  13. Systems Engineering Leadership Development: Advancing Systems Engineering Excellence

    Science.gov (United States)

    Hall, Phil; Whitfield, Susan

    2011-01-01

    This slide presentation reviews the Systems Engineering Leadership Development Program, with particular emphasis on the work being done in the development of systems engineers at Marshall Space Flight Center. There exists a lack of individuals with systems engineering expertise, in particular those with strong leadership capabilities, to meet the needs of the Agency's exploration agenda. Therefore there is a emphasis on developing these programs to identify and train systems engineers. The presentation reviews the proposed MSFC program that includes course work, and developmental assignments. The formal developmental programs at the other centers are briefly reviewed, including the Point of Contact (POC)

  14. Dynamical Systems Approaches to Emotional Development

    Science.gov (United States)

    Camras, Linda A.; Witherington, David C.

    2005-01-01

    Within the last 20 years, transitions in the conceptualization of emotion and its development have given rise to calls for an explanatory framework that captures emotional development in all its organizational complexity and variability. Recent attempts have been made to couch emotional development in terms of a dynamical systems approach through…

  15. Development of an autonomous power system testbed

    International Nuclear Information System (INIS)

    Barton, J.R.; Adams, T.; Liffring, M.E.

    1985-01-01

    A power system testbed has been assembled to advance the development of large autonomous electrical power systems required for the space station, spacecraft, and aircraft. The power system for this effort was designed to simulate single- or dual-bus autonomous power systems, or autonomous systems that reconfigure from a single bus to a dual bus following a severe fault. The approach taken was to provide a flexible power system design with two computer systems for control and management. One computer operates as the control system and performs basic control functions, data and command processing, charge control, and provides status to the second computer. The second computer contains expert system software for mission planning, load management, fault identification and recovery, and sends load and configuration commands to the control system

  16. INTEGRATED HSEQ MANAGEMENT SYSTEMS: DEVELOPMENTS AND TRENDS

    OpenAIRE

    Osmo Kauppila; Janne Härkönen; Seppo Väyrynen

    2015-01-01

    The integration of health and safety, environmental and quality (HSEQ) management systems has become a current topic in the 21st century, as the need for systems thinking has grown along with the number of management system standards. This study aims to map current developments and trends in integrated HSEQ management. Three viewpoints are taken: the current state of the main HSEQ management standards, research literature on integrated management systems (IMS), and a case study of an industry...

  17. About development of automation control systems

    Science.gov (United States)

    Myshlyaev, L. P.; Wenger, K. G.; Ivushkin, K. A.; Makarov, V. N.

    2018-05-01

    The shortcomings of approaches to the development of modern control automation systems and ways of their improvement are given: the correct formation of objects for study and optimization; a joint synthesis of control objects and control systems, an increase in the structural diversity of the elements of control systems. Diagrams of control systems with purposefully variable structure of their elements are presented. Structures of control algorithms for an object with a purposefully variable structure are given.

  18. System model development for nuclear thermal propulsion

    International Nuclear Information System (INIS)

    Walton, J.T.; Perkins, K.R.; Buksa, J.J.; Worley, B.A.; Dobranich, D.

    1992-01-01

    A critical enabling technology in the evolutionary development of nuclear thermal propulsion (NTP) is the ability to predict the system performance under a variety of operating conditions. Since October 1991, US (DOE), (DOD) and NASA have initiated critical technology development efforts for NTP systems to be used on Space Exploration Initiative (SEI) missions to the Moon and Mars. This paper presents the strategy and progress of an interagency NASA/DOE/DOD team for NTP system modeling. It is the intent of the interagency team to develop several levels of computer programs to simulate various NTP systems. An interagency team was formed for this task to use the best capabilities available and to assure appropriate peer review. The vision and strategy of the interagency team for developing NTP system models will be discussed in this paper. A review of the progress on the Level 1 interagency model is also presented

  19. Gas tagging system development in Japan

    International Nuclear Information System (INIS)

    Sekiguchi, N.; Rindo, H.; Akiyama, T.; Miyazawa, T.; Heki, H.

    1981-05-01

    The Gas tagging method has been considered to be most desirable for a failed fuel location system for the fast breeder reactor, regarding the component reduction in the reactor vessel and rapid location during reactor operation. The gas tagging system has been designed by referring to R and D results obtained in Japan and other countries. The designed system is comprised of tag gas filling pins, cover gas sampling system, tag gas recovery and enrichment system, tag gas analyzer and system control and data handling computers. The main specifications for this system have been decided as follows; 1) Main function is location of failed fuels in core and a part of blanket region, 2) Identification capability is each subassembly, 3) Time for identification is within a few days, 4) Continuous operation with automatic start at fuel failure, 5) Detection sensitivity must cover both gas leak and pin burst. In designing the gas tagging system, the following R and D items were selected; 1) System design study, 2) Tag gas capsule development, 3) Modeling the tag gas behavior in reactor primary cooling system, 4) Tag gas recovery and enrichment system, 5) Computer code development for tag gas isotope ratio change estimation. Details of the Japanese gas tagging system development appear in this paper. (author)

  20. A Software Development Platform for Mechatronic Systems

    DEFF Research Database (Denmark)

    Guan, Wei

    Software has become increasingly determinative for development of mechatronic systems, which underscores the importance of demands for shortened time-to-market, increased productivity, higher quality, and improved dependability. As the complexity of systems is dramatically increasing, these demands...... present a challenge to the practitioners who adopt conventional software development approach. An effective approach towards industrial production of software for mechatronic systems is needed. This approach requires a disciplined engineering process that encompasses model-driven engineering and component......-based software engineering, whereby we enable incremental software development using component models to address the essential design issues of real-time embedded systems. To this end, this dissertation presents a software development platform that provides an incremental model-driven development process based...

  1. Development of the Digital Reactor Safety System

    International Nuclear Information System (INIS)

    Lee, Dong Young; Lee, C. K.; Hwang, I. K.

    2008-04-01

    Objectives of Project - Development of Digital Safety Grade PLC and Licensing - Development of Safety System(RPS) and Licensing - Development of Safety System(ESF-CCS) and Licensing Content and Result of Project - POSAFE-Q PLC : Development of PLC platform for Shin-UCN unit 1 and 2 ·Development Scope : Processor module, Power module, 3 kinds of Communication module, Bus extension module(Master and Slave), 16 kinds of Input and Output module ·PLC application software development tool(pSET) - IDiPS RPS and IDiPS ESF-CCS : Development of PPS for Sin-UCN 1 and 2 ·Development Scope - 4-channels RPS with the KNICS inherent architecture - A part of 1-channels ESF-CCS with the KNICS inherent architecture - Licensing ·optical Report Submitted and Expected to finish the licensing process until Aug. 2008

  2. Development of environment radiation database management system

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Jong Gyu; Chung, Chang Hwa; Ryu, Chan Ho; Lee, Jin Yeong; Kim, Dong Hui; Lee, Hun Sun [Daeduk College, Taejon (Korea, Republic of)

    1999-03-15

    In this development, we constructed a database for efficient data processing and operating of radiation-environment related data. Se developed the source documents retrieval system and the current status printing system that supports a radiation environment dta collection, pre-processing and analysis. And, we designed and implemented the user interfaces and DB access routines based on WWW service policies on KINS Intranet. It is expected that the developed system, which organizes the information related to environmental radiation data systematically can be utilize for the accurate interpretation, analysis and evaluation.

  3. On Using Materiality in Information Systems Development

    DEFF Research Database (Denmark)

    Carugati, Andrea

    This research brief presents a discussion on the use of the concept of materiality and material knowing in information systems development (ISD). The discussion addresses some of the practical problems still plaguing ISD, augmenting existing ISD methodologies with contributions from systems theory...... as scaffold of knowledge. Through the example taken from a case study of a complex and innovative systems development we outline two design principles to be embedded in modular fashion in ISD processes: (1) whenever possible start ISD efforts by developing a graphical simulator of the material environment...

  4. Development of environment radiation database management system

    International Nuclear Information System (INIS)

    Kang, Jong Gyu; Chung, Chang Hwa; Ryu, Chan Ho; Lee, Jin Yeong; Kim, Dong Hui; Lee, Hun Sun

    1999-03-01

    In this development, we constructed a database for efficient data processing and operating of radiation-environment related data. Se developed the source documents retrieval system and the current status printing system that supports a radiation environment dta collection, pre-processing and analysis. And, we designed and implemented the user interfaces and DB access routines based on WWW service policies on KINS Intranet. It is expected that the developed system, which organizes the information related to environmental radiation data systematically can be utilize for the accurate interpretation, analysis and evaluation

  5. d = 2 transverse-field Ising model under the screw-boundary condition: an optimization of the screw pitch

    International Nuclear Information System (INIS)

    Nishiyama, Yoshihiro

    2011-01-01

    A length-N spin chain with the √N(=v)th neighbor interaction is identical to a two-dimensional (d = 2) model under the screw-boundary (SB) condition. The SB condition provides a flexible scheme to construct a d ≥ 2 cluster from an arbitrary number of spins; the numerical diagonalization combined with the SB condition admits a potential applicability to a class of systems intractable with the quantum Monte Carlo method due to the negative-sign problem. However, the simulation results suffer from characteristic finite-size corrections inherent in SB. In order to suppress these corrections, we adjust the screw pitch v(N) so as to minimize the excitation gap for each N. This idea is adapted to the transverse-field Ising model on the triangular lattice with N ≤ 32 spins. As a demonstration, the correlation-length critical exponent ν is analyzed in some detail

  6. Concurrence of dynamical phase transitions at finite temperature in the fully connected transverse-field Ising model

    Science.gov (United States)

    Lang, Johannes; Frank, Bernhard; Halimeh, Jad C.

    2018-05-01

    We construct the finite-temperature dynamical phase diagram of the fully connected transverse-field Ising model from the vantage point of two disparate concepts of dynamical criticality. An analytical derivation of the classical dynamics and exact diagonalization simulations are used to study the dynamics after a quantum quench in the system prepared in a thermal equilibrium state. The different dynamical phases characterized by the type of nonanalyticities that emerge in an appropriately defined Loschmidt-echo return rate directly correspond to the dynamical phases determined by the spontaneous breaking of Z2 symmetry in the long-time steady state. The dynamical phase diagram is qualitatively different depending on whether the initial thermal state is ferromagnetic or paramagnetic. Whereas the former leads to a dynamical phase diagram that can be directly related to its equilibrium counterpart, the latter gives rise to a divergent dynamical critical temperature at vanishing final transverse-field strength.

  7. Prognostication of regional energy system development

    Directory of Open Access Journals (Sweden)

    Grigoriy Borisovich Korovin

    2011-06-01

    Full Text Available This paper analyzes practice and development of new methodological approaches to forecasting the development of regional energy systems. It is shown that the energy complex is involved in a variety of forward and backward linkages as an element of socio-economic systems, and the quality and availability of energy resources largely determines the structure and pace of economic, social and environmental development of the region. Analysis of existing current practice of territorial and sectoral forecasting implemented in Russia and abroad, suggests that such practice is inadequate in its theoretical and methodological elaboration. This is confirmed by the frequent discrepancy between actual results and plans, as well as their regular revision. The methods are mostly based on extrapolation of existing tendencies and not taking into account many factors and emerging trends related to the complexity and openness of the social and economic systems. Post-industrial level of civilization is characterized by fast development of technology; knowledge, information, technological and institutional innovation become the main resources. The greatest importance is attached to such development properties as instability, various orderliness, nonlinearity, interactions etc. Current approaches to forecasting the future are described by a number of theories that are generally called self-organization theory, taking into account these singularities. These concepts should be included in the theoretical basis for the development and implementation of regional development forecasts. Using the synergetic approach assumes that, along with organizational processes, processes of self-organization and self-development are very important in the system, they are characterized by spontaneous, unexpected formations and emerging structures. The development of such systems can generate stable and efficient new structure. The presence of crisis is an integral feature of complex

  8. System theoretic approach to sustainable development problems

    Directory of Open Access Journals (Sweden)

    Batanović Vladan

    2011-01-01

    Full Text Available This paper shows that the concepts and methodology contained in the system theory and operations research are suitable for application in the planning and control of the sustainable development. The sustainable development problems can be represented using the state space concepts, such as the transition of system, from the given initial state to the final state. It is shown that sustainable development represents a specific control problem. The peculiarity of the sustainable development is that the target is to keep the system in the prescribed feasible region of the state space. The analysis of planning and control problems of sustainable development has also shown that methods developed in the operations research area, such as multicriteria optimization, dynamic processes simulation, non-conventional treatment of uncertainty etc. are adequate, exact base, suitable for resolution of these problems.

  9. Development of vitrified waste storage system

    International Nuclear Information System (INIS)

    Namiki, S.; Tani, Y.

    1993-01-01

    The authors have developed the radioactive waste vitrification technology and the vitrified waste storage technology. Regarding the vitrified waste storage system development, the authors have completed the design of two types of storage systems. One is a forced convection air cooling system, and the other is a natural convection air cooling system. They have carried out experiments and heat transfer analysis, seismic analysis, vitrified waste dropping and radiation shielding, etc. In this paper, the following three subjects, are discussed: the cooling air flow experiment, the wind effect experiment on the cooling air flow pattern, using a wind tunnel apparatus and the structural integrity evaluation on the dropping vitrified waste

  10. Effect of the Hamiltonian parameters on the hysteresis properties of the kinetic mixed spin (1/2, 1) Ising ferrimagnetic model on a hexagonal lattice

    Energy Technology Data Exchange (ETDEWEB)

    Batı, Mehmet, E-mail: mehmet.bati@erdogan.edu.tr [Department of Physics, Recep Tayyip Erdoğan University, 53100 Rize (Turkey); Ertaş, Mehmet [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

    2017-05-15

    The hysteresis properties of a kinetic mixed spin (1/2, 1) Ising ferrimagnetic system on a hexagonal lattice are studied by means of the dynamic mean field theory. In the present study, the effects of the nearest-neighbor interaction, temperature, frequency of oscillating magnetic field and the exchange anisotropy on the hysteresis properties of the kinetic system are discussed in detail. A number of interesting phenomena such as the shape of hysteresis loops with one, two, three and inverted-hysteresis/proteresis (butterfly shape hysteresis) have been obtained. Finally, the obtained results are compared with some experimental and theoretical results and a qualitatively good agreement is found.

  11. Training Systems Modelers through the Development of a Multi-scale Chagas Disease Risk Model

    Science.gov (United States)

    Hanley, J.; Stevens-Goodnight, S.; Kulkarni, S.; Bustamante, D.; Fytilis, N.; Goff, P.; Monroy, C.; Morrissey, L. A.; Orantes, L.; Stevens, L.; Dorn, P.; Lucero, D.; Rios, J.; Rizzo, D. M.

    2012-12-01

    The goal of our NSF-sponsored Division of Behavioral and Cognitive Sciences grant is to create a multidisciplinary approach to develop spatially explicit models of vector-borne disease risk using Chagas disease as our model. Chagas disease is a parasitic disease endemic to Latin America that afflicts an estimated 10 million people. The causative agent (Trypanosoma cruzi) is most commonly transmitted to humans by blood feeding triatomine insect vectors. Our objectives are: (1) advance knowledge on the multiple interacting factors affecting the transmission of Chagas disease, and (2) provide next generation genomic and spatial analysis tools applicable to the study of other vector-borne diseases worldwide. This funding is a collaborative effort between the RSENR (UVM), the School of Engineering (UVM), the Department of Biology (UVM), the Department of Biological Sciences (Loyola (New Orleans)) and the Laboratory of Applied Entomology and Parasitology (Universidad de San Carlos). Throughout this five-year study, multi-educational groups (i.e., high school, undergraduate, graduate, and postdoctoral) will be trained in systems modeling. This systems approach challenges students to incorporate environmental, social, and economic as well as technical aspects and enables modelers to simulate and visualize topics that would either be too expensive, complex or difficult to study directly (Yasar and Landau 2003). We launch this research by developing a set of multi-scale, epidemiological models of Chagas disease risk using STELLA® software v.9.1.3 (isee systems, inc., Lebanon, NH). We use this particular system dynamics software as a starting point because of its simple graphical user interface (e.g., behavior-over-time graphs, stock/flow diagrams, and causal loops). To date, high school and undergraduate students have created a set of multi-scale (i.e., homestead, village, and regional) disease models. Modeling the system at multiple spatial scales forces recognition that

  12. Automated Operations Development for Advanced Exploration Systems

    Science.gov (United States)

    Haddock, Angie T.; Stetson, Howard

    2012-01-01

    Automated space operations command and control software development and its implementation must be an integral part of the vehicle design effort. The software design must encompass autonomous fault detection, isolation, recovery capabilities and also provide "single button" intelligent functions for the crew. Development, operations and safety approval experience with the Timeliner system onboard the International Space Station (ISS), which provided autonomous monitoring with response and single command functionality of payload systems, can be built upon for future automated operations as the ISS Payload effort was the first and only autonomous command and control system to be in continuous execution (6 years), 24 hours a day, 7 days a week within a crewed spacecraft environment. Utilizing proven capabilities from the ISS Higher Active Logic (HAL) System, along with the execution component design from within the HAL 9000 Space Operating System, this design paper will detail the initial HAL System software architecture and interfaces as applied to NASA's Habitat Demonstration Unit (HDU) in support of the Advanced Exploration Systems, Autonomous Mission Operations project. The development and implementation of integrated simulators within this development effort will also be detailed and is the first step in verifying the HAL 9000 Integrated Test-Bed Component [2] designs effectiveness. This design paper will conclude with a summary of the current development status and future development goals as it pertains to automated command and control for the HDU.

  13. Trajectory of Sewerage System Development Optimization

    Science.gov (United States)

    Chupin, R. V.; Mayzel, I. V.; Chupin, V. R.

    2017-11-01

    The transition to market relations has determined a new technology for our country to manage the development of urban engineering systems. This technology has shifted to the municipal level and it can, in large, be presented in two stages. The first is the development of a scheme for the development of the water supply and sanitation system, the second is the implementation of this scheme on the basis of investment programs of utilities. In the investment programs, financial support is provided for the development and reconstruction of water disposal systems due to the investment component in the tariff, connection fees for newly commissioned capital construction projects and targeted financing for selected state and municipal programs, loans and credits. Financial provision with the development of sewerage systems becomes limited and the problem arises in their rational distribution between the construction of new water disposal facilities and the reconstruction of existing ones. The paper suggests a methodology for developing options for the development of sewerage systems, selecting the best of them by the life cycle cost criterion, taking into account the limited investments in their construction, models and methods of analysis, optimizing their reconstruction and development, taking into account reliability and seismic resistance.

  14. Core Flight System (CFS) Integrated Development Environment

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of this project is to create an Integrated Development Environment (IDE) for the Core Flight System (CFS) software to reduce the time it takes to...

  15. Developing a knowledge system for information operations

    CSIR Research Space (South Africa)

    Leenen, L

    2011-03-01

    Full Text Available In this paper we describe a research project to develop an optimal information retrieval system in an Information Operations domain. Information Operations is the application and management of information to gain an advantage over an opponent...

  16. Intermediate Systems Analyst | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... bring to the System Development Group the necessary skills to understand in depth ... Participates in collaborative technical discussions with IDRC management, ... Responsible to monitor and oversee private sector consultant and part-time ...

  17. Research and Development Information System (RDIS)

    Data.gov (United States)

    Department of Veterans Affairs — The Research and Development Information System (RDIS) is the Veterans Affairs Central Office budgetary and project data repository for managing the VA Research and...

  18. Systems strategies for developing industrial microbial strains

    DEFF Research Database (Denmark)

    Lee, Sang Yup; Kim, Hyun Uk

    2015-01-01

    Industrial strain development requires system-wide engineering and optimization of cellular metabolism while considering industrially relevant fermentation and recovery processes. It can be conceptualized as several strategies, which may be implemented in an iterative fashion and in different...

  19. Exemplar PV system for test and development

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    This report describes the construction of Reference Photovoltaic System for Test and Development at University of Southampton between April 1995 and June 2000, which subsequently became known as the STaR Facility. (author)

  20. System Administrator for LCS Development Sets

    Science.gov (United States)

    Garcia, Aaron

    2013-01-01

    The Spaceport Command and Control System Project is creating a Checkout and Control System that will eventually launch the next generation of vehicles from Kennedy Space Center. KSC has a large set of Development and Operational equipment already deployed in several facilities, including the Launch Control Center, which requires support. The position of System Administrator will complete tasks across multiple platforms (Linux/Windows), many of them virtual. The Hardware Branch of the Control and Data Systems Division at the Kennedy Space Center uses system administrators for a variety of tasks. The position of system administrator comes with many responsibilities which include maintaining computer systems, repair or set up hardware, install software, create backups and recover drive images are a sample of jobs which one must complete. Other duties may include working with clients in person or over the phone and resolving their computer system needs. Training is a major part of learning how an organization functions and operates. Taking that into consideration, NASA is no exception. Training on how to better protect the NASA computer infrastructure will be a topic to learn, followed by NASA work polices. Attending meetings and discussing progress will be expected. A system administrator will have an account with root access. Root access gives a user full access to a computer system and or network. System admins can remove critical system files and recover files using a tape backup. Problem solving will be an important skill to develop in order to complete the many tasks.