4,923 research outputs found

    "Exact" Algorithm for Random-Bond Ising Models in 2D

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    We present an efficient algorithm for calculating the properties of Ising models in two dimensions, directly in the spin basis, without the need for mapping to fermion or dimer models. The algorithm gives numerically exact results for the partition function and correlation functions at a single temperature on any planar network of N Ising spins in O(N^{3/2}) time or less. The method can handle continuous or discrete bond disorder and is especially efficient in the case of bond or site dilution, where it executes in O(L^2 ln L) time near the percolation threshold. We demonstrate its feasibility on the ferromagnetic Ising model and the +/- J random-bond Ising model (RBIM) and discuss the regime of applicability in cases of full frustration such as the Ising antiferromagnet on a triangular lattice.Comment: 4.2 pages, 5 figures, accepted for publication in Phys. Rev. Let

    Noise Predictions for STM in Systems with Local Electron Nematic Order

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    We propose that thermal noise in local stripe orientation should be readily detectable via STM on systems in which local stripe orientations are strongly affected by quenched disorder. Stripes, a unidirectional, nanoscale modulation of electronic charge, are strongly affected by quenched disorder in two-dimensional and quasi-two-dimensional systems. While stripe orientations tend to lock to major lattice directions, dopant disorder locally breaks rotational symmetry. In a host crystal with otherwise C4C_4 rotational symmetry, stripe orientations in the presence of quenched disorder map to the random field Ising model. While the low temperature state of such a system is generally a stripe glass in two dimensional or strongly layered systems, as the temperature is raised, stripe orientational fluctuations become more prevalent. We propose that these thermally excited fluctuations should be readily detectable in scanning tunneling spectroscopy as {\em telegraph noise} in the high voltage part of the local I(V)I(V) curves. We predict the spatial, temporal, and thermal evolution of such noise, including the circumstances under which such noise is most likely to be observed. In addition, we propose an in-situ test, amenable to any local scanning probe, for assessing whether such noise is due to correlated fluctuations rather than independent switchers.Comment: 8 pages, 8 figure

    Analisis Pengaruh Pertumbuhan Perusahaan, Kebijakan Utang, Collateralizable Assets, dan Ukuran Perusahaan terhadap Kebijakan Dividen pada Perusahaan Manufaktur yang Terdaftar di Bursa Efek Indonesia Periode 2012-2014

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    Companies that issued shares to raise funds, must set aside some of the profits to be distributed as dividends. Dividend policy is a policy of how large distributions to the company's shareholders in proportion to the number of shares owned. Companies should establish a policy of dividend because the distribution of dividend will have an impact on corporate value as reflected in stock prices. This study uses multiple linear regression analysis which were processed using SPSS version 22. This study aimed to examine the effect on firm growth, debt policy, collateralizable assets, and firm size to dividend policy of the company. The sample used in this study were 105 companies listed in Indonesia Stock Exchange from the period 2012-2014. Empirically, it was found that the firm growth and firm size were affected to the dividend policy of the company, while the debt policy and collateralizable assets were not affected to the dividend policy of the company

    Analisis Pengaruh Perjanjian Utang, Kepemilikan Institusional, dan Ukuran Perusahaan terhadap Manajemen Laba Riil pada Perusahaan Manufaktur yang Terdaftar di Bursa Efek Indonesia

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    Real Earnings Management is the real operating management activities undertaken by  manager for a particular purpose.  Real earnings management directly affect the cash flows of current and future, also the amount of accrual accounting, making it difficult to be monitored and detected by the board, auditors, regulators, and other stakeholders, as well as difficult for investors to be understood.  Therefore, companies management prefer to do real earnings management, compared to rely on accrual earnings manipulation. This research aims to determine the effect of the debt covenant, institutional ownership, and firm size to real earnings management. This research uses the method of multiple linear regression analysis, using data from the Indonesia Stock Exchange with samples of 156 companies for the period 2012 - 2014. Empirically, it was found that the debt covenant was not affected to the real earnings management, while institutional ownership and firm size were affected to the real earnings management

    Coulomb blockade and quantum tunnelling in the low-conductivity phase of granular metals

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    We study the effects of Coulomb interaction and inter-grain quantum tunnelling in an array of metallic grains using the phase-functional approach for temperatures TT well below the charging energy EcE_{c} of individual grains yet large compared to the level spacing in the grains. When the inter-grain tunnelling conductance g1g\gg1, the conductivity σ\sigma in dd dimensions decreases logarithmically with temperature (σ/σ0112πgdln(gEc/T)\sigma/\sigma_{0}\sim1-\frac{1}{2\pi gd}\ln(gE_{c}/T)), while for g0g\to0, the conductivity shows simple activated behaviour (σexp(Ec/T)\sigma \sim \exp(-E_c/T)). We show, for bare tunnelling conductance g1g \gtrsim 1, that the parameter γg(12/(gπ)ln(gEc/T))\gamma \equiv g(1-2/(g\pi)\ln(gE_{c}/T)) determines the competition between charging and tunnelling effects. At low enough temperatures in the regime 1γ1/βEc1\gtrsim \gamma \gg 1/\sqrt{\beta E_{c}}, a charge is shared among a finite number N=(Ec/T)/ln(π/2γz)N=\sqrt{(E_{c}/T)/\ln(\pi/2\gamma z)} of grains, and we find a soft activation behaviour of the conductivity, σz1exp(2(Ec/T)ln(π/2γz))\sigma\sim z^{-1}\exp(-2\sqrt{(E_{c}/T)\ln(\pi/2\gamma z)}), where zz is the effective coordination number of a grain.Comment: 11 pages REVTeX, 3 Figures. Appendix added, replaced with published versio

    Vlasov Description Of Dense Quark Matter

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    We discuss properties of quark matter at finite baryon densities and zero temperature in a Vlasov approach. We use a screened interquark Richardson's potential consistent with the indications of Lattice QCD calculations. We analyze the choices of the quark masses and the parameters entering the potential which reproduce the binding energy (B.E.) of infinite nuclear matter. There is a transition from nuclear to quark matter at densities 5 times above normal nuclear matter density. The transition could be revealed from the determination of the position of the shifted meson masses in dense baryonic matter. A scaling form of the meson masses in dense matter is given.Comment: 15 pages 4 figure

    Microminiaturized, biopotential conditioning system (MBCS)

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    Multichannel, medical monitoring system allows almost complete freedom of movement for subject during monitoring periods. System comprises monitoring unit (biobelt), transmission line, and data acquisition unit. Belt, made of polybenzimidizole fabric, is wrapped around individual's waist and held in place by overlapping sections of Velcro closure material

    Mystery of Excess Low Energy States in a Disordered Superconductor in a Zeeman Field

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    Tunneling density of states measurements of disordered superconducting (SC) Al films in high Zeeman fields reveal a significant population of subgap states which cannot be explained by standard BCS theory. We provide a natural explanation of these excess states in terms of a novel disordered Larkin-Ovchinnikov (dLO) phase that occurs near the spin-paramagnetic transition at the Chandrasekhar-Clogston critical field. The dLO superconductor is characterized by a pairing amplitude that changes sign at domain walls. These domain walls carry magnetization and support Andreev bound states, which lead to distinct spectral signatures at low energy.Comment: 5 pages, 4 figures, plus supplementary section describing methods (2 pages

    Measurement of ozone transmissivity at low temperatures

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    Low temperature medium resolution measurements of the transmissivity of the ozone band have been made in the laboratory. The range of conditions under which the measurements were made are: -48 to -22 C, .0029 U .71 atmo.cm., 680 P 742 mmHg. The apparatus used is described briefly, measurement conditions are summarized and the resulting spectra are shown
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