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December 2006 arXiv papers — page 20

Showing 1,9012,000 of 4,461 papers

  1. Eduardo D. Sontag

    This paper (parts I and II) provides an expository introduction to monotone and near-monotone dynamical systems associated to biochemical networks, those whose graphs are consistent or near-consistent. Many conclusions can be drawn from signed network structure, associated to purely stoichiometric information and ignoring fluxes. In particular, monotone syst

  2. Maksim Kouza, Chi-Fon Chang, Shura Hayryan, Tsan-hung Yu

    The folding of the alpha-helice domain hbSBD of the mammalian mitochondrial branched-chain alpha-ketoacid dehydrogenase (BCKD) complex is studied by the circular dichroism technique in absence of urea. Thermal denaturation is used to evaluate various thermodynamic parameters defining the equilibrium unfolding, which is well described by the two-state model w

  3. A. Di Mauro, B. Lund-Jensen, P. Martinengro, E. Napri

    We have developed and tested several prototypes of GEM-like detectors with electrodes coated with resistive layers: CuO or CrO. These detectors can operate stably at gains close to 10E5 and they are very robust. We discovered that the cathodes of these detectors could be coated by CsI layers and in such a way the detectors gain high efficiency for the UV pho

  4. Pratim Kumar Chattaraj, Debesh Ranjan Roy

    The aromaticity in the polyacene analogues of several inorganic ring compounds (BN-acenes, CN-acenes, BO-acenes and Na6-acenes) is reported here for the first time. Conceptual density functional theory based reactivity descriptors and the nucleus independent chemical shift (NICS) values are used in this analysis.

  5. D. Baye, E. M. Tursunov, P. Descouvemont

    The beta decay process of the 11Li halo nucleus into 9Li and d is studied in a three-body model. The 11Li nucleus is described as a 9Li+n+n system in hyperspherical coordinates on a Lagrange mesh. Various 9Li+d potentials are compared involving a forbidden state, a physical bound state, and a resonance near 0.25 MeV in the s-wave. With an added surface absor

  6. Woo-Sik Son, Jung-Wan Ryu, Dong-Uk Hwang, Soo-Young Lee

    We study the control of transport properties in a deterministic inertia ratchet system via the extended delay feedback method. A chaotic current of a deterministic inertia ratchet system is controlled to a regular current by stabilizing unstable periodic orbits embedded in a chaotic attractor of the unperturbed system. By selecting an unstable periodic orbit

  7. W. A. Berger, H. G. Miller

    The iterative algorithm recently proposed by Waxman for solving eigenvalue problems, which relies on the method of moments, has been modified to improve its convergence considerably without sacrificing its benefits or elegance. The suggested modification is based on methods to calculate low-lying eigenpairs of large bounded hermitian operators or matrices.

  8. S. Attal, A. Joye

    We compute the quantum Langevin equation (or quantum stochastic differential equation) representing the action of a quantum heat bath at thermal equilibrium on a simple quantum system. These equations are obtained by taking the continuous limit of the Hamiltonian description for repeated quantum interactions with a sequence of photons at a given density matr

  9. Jeff Viaclovsky, Gang Tian

    We make some improvements to our previous results. First, we prove a version of our volume growth theorem which does not require any assumption on the first Betti number. Second, we show that our local regularity theorem only requires a lower volume growth assumption, not a full Sobolev constant bound. These results allow us to weaken the assumptions of our

  10. Jeffrey S. Geronimo, Plamen Iliev

    We construct one and two parameter deformations of the two dimensional Chebyshev polynomials with simple recurrence coefficients, following the algorithm in [3]. Using inverse scattering techniques, we compute the corresponding orthogonality measures.

  11. Benoit Perthame, Anne-Laure Dalibard

    We are concerned with the hyperbolic Keller-Segel model with quorum sensing, a model describing the collective cell movement due to chemical signalling with a flux limitation for high cell densities. This is a first order quasilinear equation, its flux depends on space and time via the solution to an elliptic PDE in which the right hand side is the solution

  12. J. Yermolova-Magnusson, M. Samsonov, A. Stolin

    We propose a method of quantization of certain Lie bialgebra structures on the polynomial Lie algebras related to quasi-trigonometric solutions of the classical Yang-Baxter equation. The method is based on so-called affinization of certain seaweed algebras and their quantum analogues.

  13. Paolo Lipparini

    We provide more characterizations of varieties having a term Mal'cev modulo two functions $F$ and $G$. We characterize varieties neutral in the sense of $F$, that is varieties satisfying $R \subseteq F(R)$. We present examples of global operators satisfying the homomorphism property, in particular we show that many known commutators satisfy the homomorph

  14. Pierre-Emmanuel Caprace

    Let $\mathfrak{g}$ be a Kac-Moody algebra and $\mathfrak{b}_1, \mathfrak{b}_2$ be Borel subalgebras of opposite signs. The intersection $\mathfrak{b} = \mathfrak{b}_1 \cap \mathfrak{b}_2$ is a finite-dimensional solvable subalgebra of $\mathfrak{g}$. We show that the nilpotency degree of $[\mathfrak{b}, \mathfrak{b}]$ is bounded from above by a constant depe

  15. A. A. Bogush, V. S. Otchik, V. M. Red'kov

    By analogy with the Lobachevsky space H_{3}, generalized parabolic coordinates (t_{1},t_{2},ϕ) are introduced in Riemannian space model of positive constant curvature S_{3}. In this case parabolic coordinates turn out to be complex valued and obey additional restrictions involving the complex conjugation. In that complex coordinate system, the quantum-mechan

  16. Mingxing Luo, Sibo Zheng

    Analytic form has been obtained for four-dimensional black holes with a minimal Hawking temperature in a theory with cosmological constant, dilaton and gauge fields. In general dimensions, black hole solutions are shown to exist and their asymptotic behaviors are obtained. In theories of ten dimension, N coincident D3-branes as the boundary of an $AdS_5$ spa

  17. V. Barger, Jing Jiang, Paul Langacker, Tianjun Li

    We use a new approach to study string scale gauge coupling unification systematically, allowing both the possibility of non-canonical U(1)_Y normalization and the existence of vector-like particles whose quantum numbers are the same as those of the Standard Model (SM) fermions and their Hermitian conjugates and the SM adjoint particles. We first give all the

  18. O. V. Teryaev

    The manifestation of equivalence principle (EP) in spin-gravity interactions, resulting in the nullification of the corresponding analog of Anomalous Magnetic moment is explored. Its tests in the experiments with atoms and cold neutrons are discussed. The validity of EP separately for quarks and gluons in the nucleon resulting in exact equipartition of momen

  19. L. Selbuz, Z. Z. Aydin

    We investigate the fermionic decays of top squarks tilde t_{1,2} and bottom squarks tilde b_{1,2}$ in the Minimal Supersymmetric Standard Model with complex parameters M_1, mu, A_t and A_b . In the analysis we particularly take into account the cosmological bounds imposed by WMAP data. We plot the CP phase dependences of stop and sbottom decay widths.

  20. Yu. V. Chugreev, M. A. Mestvirishvili, K. A. Modestov

    The variant of the quintessence theory is proposed in order to get an accelerated expansion of the Friedmannian Universe in the frameworks of relativistic theory of gravitation. The substance of quintessence is built up the scalar field of dark energy. It is shown, that function V(Phi), which factorising scalar field Lagrangian (Phi is a scalar field) has no

  21. Jacob Binia

    Several proofs of the monotonicity of the non-Gaussianness (divergence with respect to a Gaussian random variable with identical second order statistics) of the sum of n independent and identically distributed (i.i.d.) random variables were published. We give an upper bound on the decrease rate of the non-Gaussianness which is proportional to the inverse of

  22. Xinjie Wang, David Vanderbilt

    We present a perturbative treatment of the response properties of insulating crystals under a dc bias field, and use this to study the effects of such bias fields on the Born effective charge tensor and dielectric tensor of insulators. We start out by expanding a variational field-dependent total-energy functional with respect to the electric field within th

  23. T. Domanski A. Donabidowicz, K. I. Wysokinski

    We analyze the charge transport through a single level quantum dot coupled to a normal (N) and superconducting (S) leads where the electron pairs exist either as the coherent (for temperatures below T_c) or incoherent objects (in a region T_c < T < T*). This situation can be achieved in practice if one uses the high T_c superconducting material where various

  24. S. Hümpfner, M. Sawicki, K. Pappert, J. Wenisch

    The focus of studies on ferromagnetic semiconductors is moving from material issues to device functionalities based on novel phenomena often associated with the anisotropy properties of these materials. This is driving a need for a method to locally control the anisotropy in order to allow the elaboration of devices. Here we present a method which provides p

  25. Ewa Gudowska-Nowak, Romuald J. Janik, Jerzy Jurkiewicz, Maciej A. Nowak

    We briefly review the random matrix theory for large N by N matrices viewed as free random variables in a context of stochastic diffusion. We establish a surprising link between the spectral properties of matrix-valued multiplicative diffusion processes for hermitian and unitary ensembles.

  26. Y. J. Uemura, T. Goko, I. M. Gat-Malureanu, J. P. Carlo

    Quantum phase transitions (QPTs) have been studied extensively in correlated electron systems. Characterization of magnetism at QPTs has, however, been limited by the volume-integrated feature of neutron and magnetization measurements and by pressure uncertainties in NMR studies using powderized specimens. Overcoming these limitations, we performed muon spin

  27. Ayan Khan, Rajneesh Atre, Prasanta K. Panigrahi

    We elaborate on a general method to find complex envelope solitons in a cigar shaped Bose-Einstein condensate in a trap. The procedure incorporates time dependent scattering length, oscillator frequency and loss/gain. A variety of time dependencies of the above parameters, akin to the ones occurring in the experiments can be tackled.

  28. L. K. Alexander, N. Buettgen, R. Nath, A. V. Mahajan

    We report 7Li NMR, magnetic susceptibility, and heat capacity measurements on the triangular lattice Heisenberg antiferromagnet compound LiCrO2. We find that in contrast to NaCrO2, magnetic properties of LiCrO2 have a more pronounced three dimensional character with sharp anomalies in the temperature variation of the 7Li NMR intensity and the NMR spin-lattic

  29. J. A. Quilliam, C. G. A. Mugford, A. Gomez, S. W. Kycia

    We present specific heat data on three samples of the dilute Ising magnet $\HoYLF$ with $x = 0.018$, 0.045 and 0.080. Previous measurements of the ac susceptibility of an $x = 0.045$ sample showed the Ho$^{3+}$ moments to remain dynamic down to very low temperatures and the specific heat was found to have unusually sharp features. In contrast, our measuremen

  30. S. R. Park, Y. S. Roh, Y. K. Yoon, C. S. Leem

    Angle resolved photoemission (ARPES) data from the electron doped cuprate superconductor Sm$_{1.86}$Ce$_{0.14}$CuO$_4$ shows a much stronger pseudo-gap or &#34;hot-spot&#34; effect than that observed in other optimally doped $n$-type cuprates. Importantly, these effects are strong enough to drive the zone-diagonal states below the chemical potential, implyin

  31. J. J. Eldridge

    Binary stars are important for a full understanding of stellar evolution. We present a summary of how predictions of the relative supernova rates varies between single and binary stars. We also show how the parameter space of different supernova types differs between single and binary stars. We then consider an important question of how to infer a supernova

  32. J. Jackiewicz, L. Gizon, A. C. Birch

    We compute f-mode sensitivity kernels for flows. Using a two-dimensional model, the scattered wavefield is calculated in the first Born approximation. We test the correctness of the kernels by comparing an exact solution (constant flow), a solution linearized in the flow, and the total integral of the kernel. In practice, the linear approximation is acceptab

  33. C. Martin Gaskell

    A model of wavelength-dependent lags in optical continuum variability of AGNs is proposed which avoids the problems of the popular ``lamp-post&#39;&#39; model. Rather than being due to reprocessing of high-energy radiation from a hypothetical source above the accretion disk, the wavelength-dependent delays observed from the B to I bands are instead due to co

  34. Xiaobo Dong, Tinggui Wang, Weimin Yuan, Hongyan Zhou

    We have conducted a systematic search of AGNs with IMBHs from the SDSS DR4. As results we found 245 candidates of broad-line AGN with M_{BH}<10^6 \Msun estimated from the luminosity and width of the broad Halpha component. Compared to the pioneer Greene & Ho (2004) sample of 19 IMBH AGNs, our sample has improved in covering a larger range of the Eddington ra

  35. Weimin Yuan, Hongyan Zhou, Tinggui Wang, Xiaobo Dong

    This proceedings contribution summarizes first results obtained from a systematic study of 2011 NLS1 galaxies, as presented in Zhou et al. (2006, ApJS 166, 128). The sample was compiled by examining the spectral parameters of galaxies and QSOs derived from SDSS DR3 data. We discuss some preliminary results on the statistic properties of the sample, such as t

  36. M. C. C. Cheung, M. Schuessler, F. Moreno-Insertis

    We study the structure and reveal the physical nature of the reversed granulation pattern in the solar photosphere by means of 3-dimensional radiative hydrodynamics simulations. We used the MURaM code to obtain a realistic model of the near-surface layers of the convection zone and the photosphere. The pattern of horizontal temperature fluctuations at the ba

  37. C. E. Navia, C. R. A. Augusto, D. F. Franceschini, K. H. Tsui

    Recent observations of the luminosity-redshift in Type Ia supernovae suggest an accelerated inflation of the Universe (open Universe) as well as the observed matter density showed to be less than the critical one, suggesting that a large fraction of the energy density of the Universe is in the form of dark energy with negative pressure (to supply repulsive f

  38. Martin Kunz, Domenico Sapone

    There is now strong observational evidence that the expansion of the universe is accelerating. The standard explanation invokes an unknown &#34;dark energy&#34; component. But such scenarios are faced with serious theoretical problems, which has led to increased interest in models where instead General Relativity is modified in a way that leads to the observ

  39. Sebastien Peirani, Scott Kay, Joe Silk

    (Context) Central active galactic nuclei (AGN) are supposed to play a key role in the evolution of their host galaxies. In particular, the dynamical and physical properties of the gas core must be affected by the injected energy. (Aims) Our aim is to study the effects of an AGN on the dark matter profile and on the central stellar light distribution in massi

  40. Miodrag Cristian Iovanov

    Let $C$ be a coalgebra. We investigate the problem of when the rational part of every finitely generated $C^*$-module $M$ is a direct summand $M$. We show that such a coalgebra must have at most countable dimension, $C$ must be artinian as right $C^*$-module and injective as left $C^*$-module. Also in this case $C^*$ is a left Noetherian ring. Following the

  41. Walter J. Christensen

    The motion of a local source inducing small oscillations in the gravitational field is investigated and shown to exhibit pure rotational kinetic energy. Should the net affect of these slow, revolving oscillations cause large-scale rotations in spacetime it would certainly result in anomalous celestial accelerations. When this angular rotational frequency of

  42. Shin&#39;ichiro Ando, Eiichiro Komatsu, Takuro Narumoto, Tomonori Totani

    The origin of the cosmic gamma-ray background (CGB) is a longstanding mystery in high-energy astrophysics. Possible candidates include ordinary astrophysical objects such as unresolved blazars, as well as more exotic processes such as dark matter annihilation. While it would be difficult to distinguish them from the mean intensity data alone, one can use ani

  43. Steffen Grønneberg

    We notice a way to execute a binary file on Windows and ELF-based systems. It can be used to create software installers and other applications not exceeding 64 kilo bytes.

  44. Wei Dai, Youjian Liu, Brian Rider

    We analyze the effect of finite rate feedback on CDMA (code-division multiple access) signature optimization and MIMO (multi-input-multi-output) beamforming vector selection. In CDMA signature optimization, for a particular user, the receiver selects a signature vector from a codebook to best avoid interference from other users, and then feeds the correspond

  45. Richard G. Clegg

    This paper examines a discrete-time queuing system with applications to telecommunications traffic. The arrival process is a particular Markov modulated process which belongs to the class of discrete batched Markovian arrival processes. The server process is a single server deterministic queue. A closed form exact solution is given for the expected queue len

  46. Jae-Hyun Yang

    In this article, we discuss the relation between Kac-Moody algebras, the monstrous moonshine, Jacobi forms and infinite products. We also review Borcherds&#39; solution of the Moonshine Conjecture and his work of constructing automorphic forms on the orthogonal group which can be written as infinite products.

  47. Dirk Tasche

    Determining contributions by sub-portfolios or single exposures to portfolio-wide economic capital for credit risk is an important risk measurement task. Often economic capital is measured as Value-at-Risk (VaR) of the portfolio loss distribution. For many of the credit portfolio risk models used in practice, the VaR contributions then have to be estimated f

  48. P. Bozhilov

    We show that for each M-theory background, having subspaces with metrics of given type, there exist M2-brane configurations, which in appropriate limit lead to two-spin magnon-like energy-charge relations, established for strings on AdS_5 x S^5, its beta-deformation, and for membrane in AdS_4 x S^7.

  49. Jesus Inarrea, Gloria Platero

    We analyze theoretically the dependence of the microwave polarization sate and sense on the magnetoresistivity response of two-dimensional electron systems. Linear and circular polarization have been considered with different senses and directions. We discuss the polarization dependence of the longitudinal magnetoresistivity and propose an explanation for th

  50. J. Bernat, Z. Masáková, E. Pelantová

    In this article, we consider the factor complexity of a fixed point of a primitive substitution canonically defined by a beta-numeration system. We provide a necessary and sufficient condition on the Renyi expansion of 1 for having an affine factor complexity map C(n), that is, such that C(n)=an+b for any integer n.

  51. Alexander Premet

    We prove that all finite W-algebras associated with nilpotent elements e in a complex semisimple Lie algebra g have finite-dimensional representations. In order to obtain this result we establish a connection between primitive ideals of U(g) attached to the nilpotent orbit containing e and finite-dimensional representations of the reduced enveloping algebra

  52. S C Tiwari

    The black hole entropy formula applied to local Rindler horizon at each spacetime point has been used in the literature to derive the Einstein field equation as an equation of state of a thermodynamical system of spacetime. In the present paper we argue that due to the key role of causal structure and discrete spacetime in this approach the natural framework

  53. M. Mohammadi, M. H. Naderi, M. Soltanolkotabi

    The temporal evolution of quantum statistical properties of an interacting atom-radiation field system in the presence of a classical homogeneous gravitational field is investigated within the framework of the Jaynes-Cummings model. To analyse the dynamical evolution of the atom-radiation system a quantum treatment of the internal and external dynamics of th

  54. M. Tomaselli, T. Kuehl, D. Ursescu

    For a better understanding of the dynamics of exotic nuclei it is of crucial importance to develop a practical microscopic theory easy to be applied to a wide range of masses. Theoretically the basic task consists in formulating an easy solvable theory able to reproduce structures and transitions of known nuclei which should be then used to calculate the spa

  55. Masato Arai, Sergei M. Kuzenko, Ulf Lindstrom

    Kahler manifolds have a natural hyperkahler structure associated with (part of) their cotangent bundles. Using projective superspace, we construct four-dimensional N = 2 models on the tangent bundles of some classical Hermitian symmetric spaces (specifically, the four regular series of irreducible compact symmetric Kahler manifolds, and their non-compact ver

  56. E. Moreno Mendez, G. E. Brown, C. -H. Lee, F. M. Walter

    Recent measurements of the Kerr parameters a* for two black-hole binaries in our Galaxy (Shafee et al. 2006), GRO J1655-40 and 4U 1543-47 of a*=0.65-0.75 and a*=0.75-0.85, respectively, fitted well the predictions of Lee et al. (2002), of a*= 0.8. In this report we also note that Lee et al. (2002) predicted a* >0.5 for 80% of the Soft X-ray Transient Sources

  57. R. S. Costas-Santos

    Often in mathematics it is useful to summarize a multivariate phenomenon with a single number and in fact, the determinant -- which is represented by det -- is one of the simplest cases. In fact, this number it is defined only for square matrices and a lot of its properties are very well-known. For instance, the determinant is a multiplicative function, i.e.

  58. Stefan Kuhr, Sébastien Gleyzes, Christine Guerlin, Julien Bernu

    We have built a microwave Fabry-Perot resonator made of diamond-machined copper mirrors coated with superconducting niobium. Its damping time (Tc = 130 ms at 51 GHz and 0.8 K) corresponds to a &#64257;nesse of 4.6 x 109, the highest ever reached for a Fabry-Perot in any frequency range. This result opens novel perspectives for quantum information, decoherenc

  59. Carina Curto

    We use F. Ferrari&#39;s methods relating matrix models to Calabi-Yau spaces in order to explain much of Intriligator and Wecht&#39;s ADE classification of $\N=1$ superconformal theories which arise as RG fixed points of $\N = 1$ SQCD theories with adjoints. We find that ADE superpotentials in the Intriligator-Wecht classification exactly match matrix model s

  60. Tibra Ali, Gerald B. Cleaver

    We derive expressions for the Ricci curvature tensor and scalar in terms of intrinsic torsion classes of half-flat manifolds by exploiting the relationship between half-flat manifolds and non-compact $G_2$ holonomy manifolds. Our expressions are tested for Iwasawa and more general nilpotent manifolds. We also derive expressions, in the language of Calabi-Yau

  61. Vladimir Nikiforov

    Some recent results on graph eigenvalues are improved. In particular, among all graphs of given order with no cliques of order $(r+1)$ the $r$-partite Turan graph has maximal spectral radius.

  62. Denys Bondar

    From the point of view of the information theory, a model of the collapse phenomena at the measurement of a spin 1/2 projection is developed. This model phenomenologically includes an observer. The model allows not only to determine the state of a system after the measurement but also to compute the state of the observer. The state of the observer is equival

  63. S C Tiwari

    We associate intrinsic energy equal to $hν/2$ with the spin angular momentum of photon and propose a topological model based on orbifold in space and tifold in time as topological obstructions. The model is substantiated using vector wavefield disclinations. The physical photon is suggested to be a particle like topological photon and a propagating wave such

  64. Uygar Ozesmi, Can Ozan Tan

    Many networks in natural and human-made systems exhibit scale-free properties and are small worlds. Now we show that people&#39;s understanding of complex systems in their cognitive maps also follow a scale-free topology (P_k = k^-lambda, lambda [1.24,3.03]; r^2 <= 0.95). People focus on a few attributes, as indicated by a fat tail in the probability distrib

  65. N. Majumdar, S. Mukhopadhyay

    Micro-Electro-Mechanical Systems (MEMS) normally have fixed or moving structures (plates or array of thin beams) with cross-sections of the order of microns and lengths of the order of tens or hundreds of microns. Electrostatic forces play a very major role in maneuvering these devices, and hence, a thorough understanding of the electrostatic properties of t

  66. S. K. Tokunaga, J. O. Stack, J. J. Hudson, B. E. Sauer

    We have developed a source of cold LiH molecules for Stark deceleration and trapping experiments. Lithium metal is ablated from a solid target into a supersonically expanding carrier gas. The translational, rotational and vibrational temperatures are 0.9(0.1) K, 5.9(0.5) K and 468(17) K respectively. Although they have not reached thermal equilibrium with th

  67. Lyderic Bocquet

    We show that the baking of potato wedges constitutes a crunchy example of edge effects, which are usually demonstrated in electrostatics. A simple model of the diffusive transport of water vapor around the potato wedges shows that the water vapor flux diverges at the sharp edges in analogy with its electrostatic counterpart. This increased evaporation at the

  68. S. A. Khairallah, M. B. Sevryuk, D. M. Ceperley, J. P. Toennies

    The interplay between magic number stabilities and superfluidity of small para-hydrogen clusters with sizes $N = 5$ to 40 and temperatures $0.5 K \leq T \leq 4.5 $K is explored with classical and quantum Path Integral Monte Carlo calculations. Clusters with $N < 26$ and T $\leq 1.5 K$ have large superfluid fractions even at the stable magic numbers 13, 19, a

  69. Tiziana Marsico, Angelo Loinger

    We prove with an exact relativistic computation that the spherosymmetric gravitational collapses with a time-dependent pressure end in bodies with a small, but finite volume. Against a diffuse, wrong conviction.

  70. Rajneesh Atre, Prasanta K. Panigrahi

    In case of the nonlinear Schrödinger equation with designed group velocity dispersion, variable nonlinearity and gain/loss; we analytically demonstrate the phenomenon of chirp reversal crucial for pulse reproduction. Two different scenarios are exhibited, where the pulses experience identical dispersion profiles, but show entirely different propagation behav

  71. E. Kelbert, A. Hyder, F. Demir, Z. T. Hlousek

    The Hamiltonian of a Coulomb plus polynomial potential on the Coulomb-Sturmian basis has an infinite symmetric band-matrix structure. A band matrix can always be considered as a block-tridiagonal matrix. So, the corresponding Green&#39;s operator can be given as a matrix-valued continued fraction. As examples, we calculate the Green&#39;s operator for the Co

  72. Miodrag C. Iovanov

    Let $\Cc$ and $\Dd$ be two corings over a ring $A$ and $\Cc\stackrelλ{\longrightarrow}\Dd$ be a morphism of corings. We investigate the situation when the associated induced (&#34;corestriction of scalars&#34;) functor $\Mm^\Cc\longrightarrow \Mm^\Dd$ is a Frobenius functor, and call these morphisms Frobenius extensions of corings. The characterization theor

  73. Holger Brenner

    We relate closure operations for ideals and for submodules to non-flat Grothendieck topologies. We show how a Grothendieck topology on an affine scheme induces a closure operation in a natural way, and how to construct for a given closure operation fulfilling certain properties a Grothendieck topology which induces this operation. In this way we relate the r

  74. Binod Kumar Sahoo

    We provide a geometrical construction of the slim dense near hexagon with parameters $(s,t,t_{2})=(2,5,\{1,2\})$. Using this construction, we construct the rank 3 symplectic dual polar space $DSp(6,2)$ which is the slim dense near hexagon with parameters $(s,t,t_{2})=(2,6,2)$. Both the near hexagons are constructed from two copies of a generalized quadrangle

  75. Ruchira S. Datta

    We prove a theorem computing the number of solutions to a system of equations which is generic subject to the sparsity conditions embodied in a graph. We apply this theorem to games obeying graphical models and to extensive-form games. We define emergent-node tree structures as additional structures which normal form games may have. We apply our theorem to g

  76. Ruchira S. Datta

    The set of Nash equilibria of a finite game is the set of nonnegative solutions to a system of polynomial equations. In this survey article we describe how to construct certain special games and explain how to find all the complex roots of the corresponding polynomial systems, including all the Nash equilibria. We then explain how to find all the complex roo

  77. Kazumasa Nomura, Paul Terwilliger

    Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of linear transformations $A:V \to V$ and $A^*:V \to V$ that satisfy (i)--(iv) below: (i) Each of $A$, $A^*$ is diagonalizable. (ii) There exists an ordering $V_{0},V_{1},...,V_{d}$ of the eigenspaces of $A$ such that $A^* V_i \subseteq V_{i-1

  78. A. Kyrieleis, J. R. Forshaw, M. H. Seymour

    We reconsider the calculation of a non-global QCD observable and find the possible breakdown of QCD coherence. This breakdown arises as a result of wide angle soft gluon emission developing a sensitivity to emission at small angles and it leads to the appearance of super-leading logarithms. We use the `gaps between jets&#39; cross-section as a concrete examp

  79. Sascha Caron, Bruce Knuteson

    Distributions from high-pT HERA event data analyzed in a general search for new physics at H1 have been incorporated into Quaero, an algorithm designed to automate tests of specific hypotheses with high energy collider data. The use of Quaero@H1 to search for leptoquarks, R-parity violating supersymmetry, and excited quarks provides examples to develop intui

  80. Thomas Baumgarte, Patrick Brady, Jolien D E Creighton, Luis Lehner

    Activities in data analysis and numerical simulation of gravitational waves have to date largely proceeded independently. In this work we study how waveforms obtained from numerical simulations could be effectively used within the data analysis effort to search for gravitational waves from black hole binaries. We propose measures to quantify the accuracy of

  81. Changbong Hyeon, D. Thirumalai

    Single molecule mechanical unfolding experiments are beginning to provide profiles of the complex energy landscape of biomolecules. In order to obtain reliable estimates of the energy landscape characteristics it is necessary to combine the experimental measurements with sound theoretical models and simulations. Here, we show how by using temperature as a va

  82. G. Esen, M. S. Fuhrer, M. Ishigami, E. D. Williams

    We measure the resistance and frequency-dependent gate capacitance of carbon nanotube (CNT) thin films in ambient, vacuum, and under low-pressure (10E-6 torr) analyte environments. We model the CNT film as an RC transmission line and show that changes in the measured capacitance as a function of gate bias and analyte pressure are consistent with changes in t

  83. David Fournier, Mario Poirier, Kim Doan Truong

    Ultrasonic velocity and attenuation measurements on the quasi-two-dimensional organic conductor $κ$-[BEDT-TTF]$_2$Cu[N(CN)$_2$]Br give the first determination of the coexistence zone of the antiferromagnetic and superconducting phases which extends deep in the metallic part of the pressure-temperature phase diagram of these salts. This zone is identified fro

  84. John P. Perdew, Lucian A. Constantin

    We construct a Laplacian-level meta-generalized gradient approximation (meta-GGA) for the non-interacting (Kohn-Sham orbital) positive kinetic energy density $τ$ of an electronic ground state of density $n$. This meta-GGA is designed to recover the fourth-order gradient expansion $τ^{GE4}$ in the appropiate slowly-varying limit and the von Weizsäcker express

  85. Johan Chang, Erik Johnson

    We present an analytical solution to the two-parabola Landau model, applied to melting of metal particles with sizes in the nanoscale range. The results provide an analytical understanding of the recently observed pseudo-crystalline phase of nanoscale Sn particles. Liquid skin formation as a precursor of melting is found to occur only for particles with radi

  86. Zhongzhi Zhang, Shuigeng Zhou, Tao Zou

    In this paper, firstly, we study analytically the topological features of a family of hierarchical lattices (HLs) from the view point of complex networks. We derive some basic properties of HLs controlled by a parameter $q$. Our results show that scale-free networks are not always small-world, and support the conjecture that self-similar scale-free networks

  87. Lucia Canova, Jozef Strecka, Jan Dely

    Magnetic properties of a ternary-spin Ising model on the decorated square lattice are studied within a generalized decoration-iteration transformation. Depending on the mutual ratio between exchange interactions and the single-ion anisotropy, there appear six different phases in the ground state. The magnetic order of these phases together with the critical

  88. Anna Posazhennikova, Babak Bayani, P. Coleman

    We discuss the physics of a of a spin-1 quantum dot, coupled to two metallic leads and develop a simple model for the temperature dependence of its conductance. Such quantum dots are described by a two-channel Kondo model with asymmetric coupling constants and the spin screening of the dot by the leads is expected to proceed via a two-stage process. When the

  89. T. Zhou, Z. D. Wang

    We propose that the presence of a rotationally symmetric charge density wave (CDW) with the modulation of 4-lattice constant in high-$T_c$ superconductors is essentially responsible for an anomalous quasiparticle dispersion revealed recently by angle-resolved photoemission spectroscopy (ARPES) experiments. We elaborate clearly that the nodal quasiparticle is

  90. Arnab Saha, J. K. Bhattacharjee

    We show, both analytically and numerically, that for a nonlinear system making a transition from one equilibrium state to another under the action of an external time dependent force, the work probability distribution is in general asymmetric.

  91. H. J. Hilhorst

    By a new Monte Carlo algorithm we evaluate the sidedness probability p_n of a planar Poisson-Voronoi cell in the range 3 \leq n \leq 1600. The algorithm is developed on the basis of earlier theoretical work; it exploits, in particular, the known asymptotic behavior of p_n as n\to\infty. Our p_n values all have between four and six significant digits. Accurat

  92. Amit Dutta, R. Loganayagam

    We study the effect of long-range connections on the infinite-randomness fixed point associated with the quantum phase transitions in a transverse Ising model (TIM). The TIM resides on a long-range connected lattice where any two sites at a distance r are connected with a non-random ferromagnetic bond with a probability that falls algebraically with the dist

  93. B. Czerny

    The presence of the dust in the circumnuclear region strongly affects our view of the nucleus itself. The effect is strong in type 2 objects but weaker effect is likely to be present in type 1 objects as well. In these objects a correction to the observed optical/UV spectrum must be done in order to recover the intrinsic spectrum of a nucleus. The approach b

  94. G. Fritz Benedict, Barbara E. McArthur, Michael W. Feast, Thomas G. Barnes

    (abridged) We present new absolute trigonometric parallaxes and relative proper motions for nine Galactic Cepheid variable stars: l Car, zeta Gem, beta Dor, W Sgr, X Sgr, Y Sgr, FF Aql, T Vul, and RT Aur. We obtain these results with astrometric data from Fine Guidance Sensor 1r, a white-light interferometer on Hubble Space Telescope. We find absolute parall

  95. W. de Boer, I. Gebauer, C. Sander, M. Weber

    The diffuse galactic EGRET gamma ray data show a clear excess for energies above 1 GeV in comparison with the expectations from conventional galactic models. This excess shows all the features expected from Dark Matter WIMP Annihilation: a)it is present and has the same spectrum in all sky directions, not just in the galactic plane, as expected for WIMP anni

  96. Adam Burrows, Luc Dessart, Christian D. Ott, Eli Livne

    In this paper, we bring together various of our published and unpublished findings from our recent 2D multi-group, flux-limited radiation hydrodynamic simulations of the collapse and explosion of the cores of massive stars. Aided by 2D and 3D graphical renditions, we motivate the acoustic mechanism of core-collapse supernova explosions and explain, as best w

  97. T. Bensby, A. R. Zenn, M. S. Oey, S. Feltzing

    We have traced the Galactic thick disk to its, to date, highest metallicities. Based on high-resolution spectroscopic observations of 187 F and G dwarf stars that kinematically can be associated either with the thin disk (60 stars) or with the thick disk (127 stars), we find that the thick disk stars reach at least solar metallicities, and maybe even higher.

  98. Michael Eisermann

    This article establishes the algebraic covering theory of quandles. For every connected quandle we explicitly construct a universal covering, which in turn leads us to define the algebraic fundamental group as the automorphism group of the universal covering. We then establish the Galois correspondence between connected coverings and subgroups of the fundame

  99. Amir H. Fariborz, Renata Jora, Joseph Schechter

    We propose a systematic procedure to study a generalized linear sigma model which can give a physical picture of possible mixing between $q{\bar q}$ and $qq{\bar q}{\bar q}$ low lying spin zero states. In the limit of zero quark masses, we derive the model independent results for the properties of the Nambu Goldstone pseudoscalar particles. For getting infor

  100. J. Gemmer, R. Umble, M. Nolan

    Consider a frictionless surface S in a gravitational field that need not be uniform. Given two points A and B on S, what curve is traced out by a particle that starts at A and reaches B in the shortest time? This paper considers this problem on simple surfaces such as surfaces of revolution and solves the problem two ways: First, we use conservation of mecha