1,649,491 research outputs found

    A new type of solution of the Schr\"odinger equation on a self-similar fractal potential

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    Scattering a quantum particle by a self-similar fractal potential on a Cantor set is investigated. We present a new type of solution of the functional equation for the transfer matrix of this potential, which was derived earlier from the Schr\"odinger equation.Comment: Latex, 4 pages, 7 eps-figures; the old figures are renewed and new ones are adde

    Spectral variability of planetary nebulae and related objects

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    The results of long-term spectral observations were used to search for changes in planetary nebulae and emission-line stars. Significant increase of excitation degree is found in two objects: M1-6 and M1-11

    Magnetic Properties and Thermal Entanglement on a Triangulated Kagome Lattice

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    The magnetic and entanglement thermal (equilibrium) properties in spin-1/2 Ising-Heisenberg model on a triangulated Kagome lattice are analyzed by means of variational mean-field like treatment based on Gibbs-Bogoliubov inequality. Because of the separable character of Ising-type exchange interactions between the Heisenberg trimers the calculation of quantum entanglement in a self-consistent field can be performed for each of the trimers individually. The concurrence in terms of three qubit isotropic Heisenberg model in effective Ising field is non-zero even in the absence of a magnetic field. The magnetic and entanglement properties exhibit common (plateau and peak) features observable via (antferromagnetic) coupling constant and external magnetic field. The critical temperature for the phase transition and threshold temperature for concurrence coincide in the case of antiferromagnetic coupling between qubits. The existence of entangled and disentangled phases in saturated and frustrated phases is established.Comment: 21 pages, 13 figure

    Entanglement Generation in the Scattering of One-Dimensional Particles

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    This article provides a convenient framework for quantitative evaluation of the entanglement generated when two structureless, distinguishable particles scatter non-relativistically in one dimension. It explores how three factors determine the amount of entanglement generated: the momentum distributions of the incoming particles, their masses, and the interaction potential. Two important scales emerge, one set by the kinematics and one set by the dynamics. This method also provides two approximate analytic formulas useful for numerical evaluation of entanglement and reveals an interesting connection between purity, linear coordinate transformations, and momentum uncertainties.Comment: 11 pages, submitted to PR

    Production of scalar KKˉK\bar K molecules in ϕ\phi radiative decays

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    The potentialities of the production of the scalar KKˉK\bar K molecules in the ϕ\phi radiative decays are considered beyond the narrow resonance width approximation. It is shown that $BR(\phi\rightarrow\gamma f_0(a_0)\rightarrow\gamma\pi\pi(\pi\eta))\approx (1\div 2)\times 10^{-5}\ ,\BR(\phi\rightarrow\gamma (f_0+a_0)\rightarrow\gamma K^+K^-)\alt 10^{-6}and and BR(\phi\rightarrow\gamma (f_0+a_0) \to \gamma K^0\bar K^0)\alt 10^{-8}.Themassspectrainthe. The mass spectra in the \pi\pi\ ,\ \pi\eta\ ,\ K^+K^-\ ,\ K^0\bar K^0channelsarecalculated.Theimaginarypartoftheamplitude channels are calculated. The imaginary part of the amplitude \phi\rightarrow\gamma f_0(a_0)iscalculatedanalytically.Itisobtainedthephaseofthescalarresonanceproductionamplitudethatcausestheinterferencepatternsinthereaction is calculated analytically. It is obtained the phase of the scalar resonance production amplitude that causes the interference patterns in the reaction e^+e^-\rightarrow\gamma \pi^+\pi^-inthe in the \phi$ meson mass region.Comment: 19 pages, revtex, 4 eps files of figure

    Arnold Tongues and Feigenbaum Exponents of the Rational Mapping for Q-state Potts Model on Recursive Lattice: Q<2

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    We considered Q-state Potts model on Bethe lattice in presence of external magnetic field for Q<2 by means of recursion relation technique. This allows to study the phase transition mechanism in terms of the obtained one dimensional rational mapping. The convergence of Feigenabaum α\alpha and δ\delta exponents for the aforementioned mapping is investigated for the period doubling and three cyclic window. We regarded the Lyapunov exponent as an order parameter for the characterization of the model and discussed its dependence on temperature and magnetic field. Arnold tongues analogs with winding numbers w=1/2, w=2/4 and w=1/3 (in the three cyclic window) are constructed for Q<2. The critical temperatures of the model are discussed and their dependence on Q is investigated. We also proposed an approximate method for constructing Arnold tongues via Feigenbaum δ\delta exponent.Comment: 15 pages, 12 figure

    Improved bounds on the number of ternary square-free words

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    Improved upper and lower bounds on the number of square-free ternary words are obtained. The upper bound is based on the enumeration of square-free ternary words up to length 110. The lower bound is derived by constructing generalised Brinkhuis triples. The problem of finding such triples can essentially be reduced to a combinatorial problem, which can efficiently be treated by computer. In particular, it is shown that the number of square-free ternary words of length n grows at least as 65^(n/40), replacing the previous best lower bound of 2^(n/17).Comment: 17 pages, AMS LaTeX. Paper has been completely rewritten and comprises new results on both lower and upper bounds. The Mathematica program mentioned in the article can be downloaded at http://mcs.open.ac.uk/ugg2/wordcomb/brinkhuistriples.
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