386,078 research outputs found

    Efficient quantum circuits for Toeplitz and Hankel matrices

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    Toeplitz and Hankel matrices have been a subject of intense interest in a wide range of science and engineering related applications. In this paper, we show that quantum circuits can efficiently implement sparse or Fourier-sparse Toeplitz and Hankel matrices. This provides an essential ingredient for solving many physical problems with Toeplitz or Hankel symmetry in the quantum setting with deterministic queries

    Rank-frequency relation for Chinese characters

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    We show that the Zipf's law for Chinese characters perfectly holds for sufficiently short texts (few thousand different characters). The scenario of its validity is similar to the Zipf's law for words in short English texts. For long Chinese texts (or for mixtures of short Chinese texts), rank-frequency relations for Chinese characters display a two-layer, hierarchic structure that combines a Zipfian power-law regime for frequent characters (first layer) with an exponential-like regime for less frequent characters (second layer). For these two layers we provide different (though related) theoretical descriptions that include the range of low-frequency characters (hapax legomena). The comparative analysis of rank-frequency relations for Chinese characters versus English words illustrates the extent to which the characters play for Chinese writers the same role as the words for those writing within alphabetical systems.Comment: To appear in European Physical Journal B (EPJ B), 2014 (22 pages, 7 figures

    Invariant graphical method for electron-atom scattering coupled-channel equations

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    We present application examples of a graphical method for the efficient construction of potential matrix elements in quantum physics or quantum chemistry. The simplicity and power of this method are illustrated through several examples. In particular, a complete set of potential matrix elements for electron-Lithium scattering are derived for the first time using this method, which removes the frozen core approximation adopted by previous studies. This method can be readily adapted to study other many-body quantum systems

    Experimental investigation of the properties of electrospun nanofibers for potential medical application

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    Copyright © 2015 Anhui Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Polymer based nanofibers using ethylene-co-vinyl alcohol (EVOH) were fabricated by electrospinning technology. The nanofibers were studied for potential use as dressing materials for skin wounds treatment. Properties closely related to the clinical requirements for wound dressing were investigated, including the fluid uptake ability (FUA), the water vapour transmission rate (WVTR), the bacteria control ability of nanofibers encapsulated with different antibacterial drugs, and Ag of various concentrations. Nanofibre degradation under different environmental conditions was also studied for the prospect of long term usage. The finding confirms the potential of EVOH nanofibers for wound dressing application, including the superior performance compared to cotton gauze and the strong germ killing capacity when Ag particles are present in the nanofibers

    Geometry and topology of two kinds of extreme Reissner-Nordstro¨\ddot{o}m-anti-de Sitter black holes

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    Different geometrical and topological properties have been shown for two kinds of extreme Reissner-Nordstro¨\ddot{o}m-anti-de Sitter black holes. The relationship between the geometrical properties and the intrinsic thermodynamical properties has been made explicit.Comment: Latex, 12 pages, 4 figure

    Statistical variability and reliability in nanoscale FinFETs

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    A comprehensive full-scale 3D simulation study of statistical variability and reliability in emerging, scaled FinFETs on SOI substrate with gate-lengths of 20nm, 14nm and 10nm and low channel doping is presented. Excellent electrostatic integrity and resulting tolerance to low channel doping are perceived as the main FinFET advantages, resulting in a dramatic reduction of statistical variability due to random discrete dopants (RDD). It is found that line edge roughness (LER), metal gate granularity (MGG) and interface trapped charges (ITC) dominate the parameter fluctuations with different distribution features, while RDD may result in relatively rare but significant changes in the device characteristics

    Magnetic field twist driven by remote convective motions: Characteristics and twist rates

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    It is generally believed that convective motions below the solar photosphere induce a twist in the coronal magnetic field as a result of frozen-in physics. A question of interest is how much twist can one expect from a persistent convective motion, given the fact that dissipative effects will eventually figure. This question is examined by considering a model problem: two conducting plates, with finite resistivity, are set in sheared motion and forced at constant relative speed. A resistive plasma is between the plates and an initially vertical magnetic field connects the plates. The time rate of tilt experienced by the field is obtained as a function of Hartmann number and the resistivity ratio. Both analytical and numerical approaches are considered

    Thermodynamics, phase transitions and Ruppeiner geometry for Einstein-dilaton Lifshitz black holes in the presence of Maxwell and Born-Infeld electrodynamics

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    In this paper, we first obtain the (n+1n+1)-dimensional dilaton-Lifshitz black hole (BH) solutions in the presence of Born-Infeld (BI) electrodynamics. We find that there are two different solutions for z=n+1z=n+1 and zn+1z\neq n+1 cases (zz is dynamical critical exponent). We show that the thermodynamics first law is satisfied for both cases. Then, we turn to study different phase transitions (PTs) for our BHs. We start with study of Hawking-Page PT for both linearly and BI charged BHs. After that, we discuss the PTs inside the BHs. We present the improved Davies quantities and prove that the PT points shown by them coincide with Ruppeiner ones. We show that the zero temperature PTs are transitions on radiance properties of BHs by using Landau-Lifshitz theory. Next, we turn to study Ruppeiner geometry of linearly and BI charged BHs. For linearly charged case, we show that there are no PT at finite temperature for the case z2z\geq 2. For z<2z<2, it is found that the number of finite temperature PT points depends on the value of BH charge and is not more than two. When we have two finite temperature PT points, there are no thermally stable BH between these two points and we have discontinues small/large BH PTs. As expected, for small BHs, we observe finite magnitude for Ruppeiner invariant which shows the finite correlation between possible BH molecules while for large BHs, the correlation is very small. Finally, we study the Ruppeiner geometry and thermal stability of BI charged Lifshtiz BHs for different values of zz. We observe that small BHs are thermally unstable in some situations. Also, the behavior of correlation between possible BH molecules for large BHs is the same as linearly charged case. In both linearly and BI charged cases, for some choices of parameters, the BH systems behave like a Van der Waals gas near transition point.Comment: V2: 23 pages (revtex format), 13 figures (except one, all include subfigures), some references adde
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