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October 2006 arXiv papers — page 42

Showing 4,1014,200 of 5,236 papers

  1. Guanyu Wang, Michael W. Deem

    Competition within the immune system may degrade immune control of viral infections. We formalize the evolution that occurs in both HIV-1 and the immune system quasispecies. Inclusion of competition in the immune system leads to a novel balance between the immune response and HIV-1, in which the eventual outcome is HIV-1 escape rather than control. The analy

  2. Wen-Rong Dai, De-Xing Kong, Kefeng Liu

    In this paper we establish the short-time existence and uniqueness theorem for hyperbolic geometric flow, and prove the nonlinear stability of hyperbolic geometric flow defined on the Euclidean space with dimension larger than 4. Wave equations satisfied by the curvatures are derived. The relation of hypergeometric flow to the Einstein equation and the Ricci

  3. Firmin J. Oliveira

    The Hubble law is extended to massive particles based on the de Broglie wavelength. Due to the expansion of the universe the wavelength of an unbound particle would increase according to its cosmological redshift. Based on the navigation anomalies of the Pioneer 10 & 11 spacecraft it is postulated that an unbound massive particle has a cosmological redshift

  4. Andrei Khrennikov, Guillaume Adenier, Theo M. Nieuwenhuizen

    This is a transcript of the round table that took place during the conference Quantum Theory: Reconsideration of Foundations - 3, June 2005, Vaxjo, Sweden. There are presented opinions of leading experts in quantum foundations on such fundamental problems as the origin of quantum fluctuations and completeness of quantum mechanics.

  5. Philip Davies

    In this paper we describe a new family of algebras which in the case of n = 2 reduces to the Fermion algebra and in the limiting case of n tends to infinity reduces to the Boson algebra. These generalized algebras describe particles which obey a generalized exclusion principle, limiting state occupation to (n-1) and obeying a generalized particle statistics.

  6. Da-Chuang Li, Zhuo-Liang Cao

    We present two schemes for teleporting an unknown two-particle entangled state from a sender (Alice) to a receiver (Bob) via a four-particle entangled cluster state. As it is shown, the unknown two-particle entangled state can be teleported perfectly, and the successful possibilities and fidelities of the two schemes both reach unit.

  7. M. W. J. Bromley, J. Mitroy

    The Configuration Interaction method is used to demonstrate that there is an electronically stable state of positronic calcium with an orbital angular momentum of L=1. This prediction relies on the use of an asymptotic series to estimate the variational limit of the energy. The best estimate of the binding energy is 37 meV. A discussion of the structure of t

  8. M. J. Leitch

    At the Relativistic Heavy Ion Collider (RHIC) collisions of heavy ions at nucleon-nucleon energies of 200 GeV appear to have created a new form of matter thought to be a deconfined state of the partons that ordinarily are bound in nucleons.We discuss the evidence that a thermalized partonic medium, usually called a Quark Gluon Plasma (QGP), has been produced

  9. Ingrid Bauer, Fabrizio Catanese, Fritz Grunewald

    We classify all the surfaces with p_g = q = 0 which admit an unramified covering which is isomorphic to a product of curves. Beyond the trivial case \PP^1 x \PP^1 we find 17 families which we explicitly describe. We reduce the problem to a combinatorial description of certain generating systems for finite groups which we solve using also MAGMA's library

  10. Carlos E. Kenig, Frank Merle

    We prove, for the energy critical, focusing NLS, that for data whose energy is smaller than that of the standing wave, and whose homogeneous Sobolev norm H^1 is smaller than that of the standing wave and which is radial, we have global well-posedness and scattering in dimensions 3, 4 and 5. This is sharp since if the data is in the inhomogeneous Sobolev spac

  11. JF. Colombeau

    It has been widely believed for half a century that there will never exist a nonlinear theory of generalized functions, in any mathematical context. The aim of this text is to show the converse is the case and invite the reader to participate in the debate and to examine the consequences at an unexpectedly elementary level. The paradox appears as another ins

  12. Nurlan S. Dairbekov, Gabriel P. Paternain

    We show that an arbitrary Anosov Gaussian thermostat close to equilibrium has positive entropy poduction unless the external field $E$ has a global potential. The configuration space is allowed to have any dimension and magnetic forces are also allowed. We also show the following non-perturbative result. Suppose a Gaussian thermostat satisfies \[K_{w}(σ)+{1/

  13. L. Sunil Chandran, Mathew C. Francis, Naveen Sivadasan

    An axis-parallel $d$--dimensional box is a Cartesian product $R_1 \times R_2 \times ... \times R_d$ where $R_i$ (for $1 \le i \le d$) is a closed interval of the form $[a_i, b_i]$ on the real line. For a graph $G$, its \emph{boxicity} $\boxi(G)$ is the minimum dimension $d$, such that $G$ is representable as the intersection graph of (axis--parallel) boxes i

  14. Mike Stillman, Damiano Testa, Mauricio Velasco

    We introduce the notion of monomial group action and study some of its consequences for Groebner basis theory. As an application we prove a conjecture of V. Batyrev and O. Popov describing the Cox rings of Del Pezzo surfaces (of degree at least 3) as quotients of a polynomial ring by an ideal generated by quadrics.

  15. Tom Leinster

    The Euler characteristic of a finite category is defined and shown to be compatible with Euler characteristics of other types of object, including orbifolds. A formula for the cardinality of the colimit of a diagram of sets is proved, generalizing the classical inclusion-exclusion formula. Both rest on a generalization of Mobius-Rota inversion from posets to

  16. Lizhou Chen

    We obtain an upper bound of the number of collisions of any billiard trajectory in a polyhedral angle in terms of the minimal eigenvalue of a positive definite matrix which characterizes the angle. Elements of the matrix are scalar products between the unit normal vectors of faces of the angle.

  17. Ole H. Hald, Panagiotis Stinis

    The "t-model" for dimensional reduction is applied to the estimation of the rate of decay of solutions of the Burgers equation and of the Euler equations in two and three space dimensions. The model was first derived in a statistical mechanics context, but here we analyze it purely as a numerical tool and prove its convergence. In the Burgers case th

  18. Alexey V. Shchepetilov

    We consider the reduced two-body problem with the Newton and the oscillator potentials on the sphere ${\bf S}^{2}$ and the hyperbolic plane ${\bf H}^{2}$. For both types of interaction we prove the nonexistence of an additional meromorphic integral for the complexified dynamic systems.

  19. Lizhou Chen

    We prove the Murphy and Cohen's conjecture that the maximum number of collisions of n + 1 elastic particles moving freely on a line is n(n+1)/2 if no interior particle has mass less than the arithmetic mean of the masses of its immediate neighbors. In fact, we prove the stronger result that, for the same conclusion, the condition no interior particle has

  20. Jayadev S. Athreya

    We prove quantitative recurrence and large deviations results for the Teichmuller geodesci flow on a connected component of a stratum of the moduli space $Q_g$ of holomorphic unit-area quadratic differentials on a compact genus $g \geq 2$ surface.

  21. P. Ara, M. A. Moreno, E. Pardo

    We compute the monoid $V(L_K(E))$ of isomorphism classes of finitely generated projective modules over certain graph algebras $L_K(E)$, and we show that this monoid satisfies the refinement property and separative cancellation. We also show that there is a natural isomorphism between the lattice of graded ideals of $L_K(E)$ and the lattice of order-ideals of

  22. D. H. Delphenich

    Some of the basic notions of nonlinear optics are summarized and then applied to the case of the Dirac vacuum, as described by the Heisenberg-Euler effective one-loop Lagrangian. The theoretical and experimental basis for the appearance of nonlinear optical phenomena, such as the Kerr effect, Cotton-Mouton effect, and four-wave mixing are discussed. Further

  23. A. Sheykhi, N. Riazi

    We construct a new class of $(n+1)$-dimensional $(n\geq3)$ black hole solutions in Einstein-Born-Infeld-dilaton gravity with Liouville-type potential for the dilaton field and investigate their properties. These solutions are neither asymptotically flat nor (anti)-de Sitter. We find that these solutions can represent black holes, with inner and outer event h

  24. A. G. Oganesian

    Some very unusual features of the hadron structure functions, obtained in the generalized QCD sum rules, like the surprisingly strong difference between longitudinally and transversally polarized $ρ$ mesons structure functions and the strong suppression of the gluon sea in longitudinally polarized $ρ$ mesons are discussed. Also the problem of exact zero cont

  25. Saeid Paktinat Mehdiabadi

    An inclusive search for low mass SUSY using the top plus missing transverse energy signature at CMS is presented. A 5$σ$ excess can be observed with $\sim$250 pb$^{-1}$ at a particular low mass SUSY point. With the same analysis selection the 5$σ$ discovery reach contours in the mSUGRA parameter space for 1 and 10 fb$^{-1}$ are obtained.

  26. M. Ablikim

    The absolute branching fraction for the decay $D^+ \to {\bar K}^0μ^+ν_μ$ is determined using $5321 \pm 149 \pm160$ singly tagged $D^-$ sample from the data collected around 3.773 GeV with the BESII detector at the BEPC collider. In the system recoiling against the singly tagged $D^-$ mesons, $28.7 \pm 6.4$ events for $D^+ \to {\bar K}^0μ^+ν_μ$ are observed.

  27. D. H. Delphenich

    It is shown that not all linear electromagnetic constitutive laws will define almost-complex structure on the bundle of 2-forms on the spacetime manifold when composed with the Poincare duality isomorphism, but only a restricted class of them that includes linear spatially isotropic and some bi-isotropic laws. Although this does not trivialize the formulatio

  28. Neil Rubens

    The quality of the ranking function is an important factor that determines the quality of the Information Retrieval system. Each document is assigned a score by the ranking function; the score indicates the likelihood of relevance of the document given a query. In the vector space model, the ranking function is defined by a mathematic expression. We propose

  29. E. A. Tolkachev, L. M. Tomilchik

    We comment on recent e-print by L. Mardoyan et al. [cond-mat/0609768]

  30. M. D. Zviadadze, A. G. Kvirikadze, R. L. Lepsveridze, G. I. Mamniashvili

    The relaxation oscillations of Zeeman and dipole magnetizaions in spin system of a solid paramagnet are theoretically analyzed under conditions of intermediate saturation of magnetic resonance and strong low-frequency modulation of the external magnetic field. Peculiarities of the relaxation oscillations in the synchronous detection regime are considered.

  31. Juan Jose Garcia-Ripoll

    In this work we develop several new simulation algorithms for 1D many-body quantum mechanical systems combining the Matrix Product State variational ansatz with Taylor, Padé and Arnoldi approximations to the evolution operator. By comparing with previous techniques based on MPS and DMRG we demonstrate that the Arnoldi method is the best one, reaching extreme

  32. A. A. Sinchenko, Yu. I. Latyshev, A. P. Orlov, P. Monceau

    A pronounced asymmetry of magnetoresistance with respect to the magnetic field direction is observed for NbSe$_3$ crystals placed in a magnetic field perpendicular to their conducting planes. It is shown that the effect persists in a wide temperature range and manifests itself starting from a certain magnetic induction value $B_0$, which at $T=4.2$ K corresp

  33. G. M. Batt, D. A. Rowlands

    A general method is proposed for calculating a fully k-dependent, continuous, and causal spectral function A(k,E) within the recently introduced nonlocal version of the coherent-potential approximation (NLCPA). The method involves the combination of both periodic and anti-periodic solutions to the associated cluster problem and also leads to correct bulk qua

  34. K. Kikoin, Y. Oreg

    We study the possibility to observe the two channel Kondo physics in multiple quantum dot heterostructures in the presence of magnetic field. We show that a fine tuning of the coupling parameters of the system and an external magnetic field may stabilize the two channel Kondo critical point. We make predictions for behavior of the scaling of the differential

  35. Bin Liu, Li-Bin Fu, Shi-Ping Yang, Jie Liu

    We investigate the tunnelling dynamics of Bose-Einstein-Condensates(BECs) in a symmetric as well as in a tilted triple-well trap within the framework of mean-field treatment. The eigenenergies as the functions of the zero-point energy difference between the tilted wells show a striking entangled star structure when the atomic interaction is large. We then ac

  36. Hagai Netzer

    Recent Chandra observations of an outflowing gas in GRO J1655-40 resulted in a suggestion by Miller et al. (2006) that the wind in this system must be powered by a magnetic process that can also drive accretion through the disk around the black hole. The alternative explanations, of radiation pressure or thermally driven flows, were considered unsatisfactory

  37. M. J. Page, F. J. Carrera, J. Ebrero, J. A. Stevens

    Unexpected in the AGN unified scheme, there exists a population of broad-line z~2 QSOs which have heavily absorbed X-ray spectra. These objects constitute 10% of the population at luminosities and redshifts characteristic of the main producers of QSO luminosity in the Universe. Our follow up observations in the submm show that these QSOs are often embedded i

  38. Yu. V. Dumin

    The effect of "dark energy" (i.e. the Lambda-term in Einstein equations) is sought for at the interplanetary scales by comparing the rates of secular increase in the lunar orbit obtained by two different ways: (1) measured immediately by the laser ranging and (2) estimated independently from the deceleration of the Earth's proper rotation. The fi

  39. M. A. Caprio, F. Iachello

    Exact solutions of the Bohr Hamiltonian with a five-dimensional square well potential, in isolation or coupled to a fermion by the five-dimensional spin-orbit interaction, are considered as examples of a new class of dynamical symmetry or Bose-Fermi dynamical symmetry. The solutions provide baselines for experimental studies of even-even [E(5)] and odd-mass

  40. Sankaran Viswanath

    We introduce a generalization of the classical Hall-Littlewood and Kostka-Foulkes polynomials to all symmetrizable Kac-Moody algebras. We prove that these Kostka-Foulkes polynomials coincide with the natural generalization of Lusztig's $t$-analog of weight multiplicities, thereby extending a theorem of Kato. For $g$ an affine Kac-Moody algebra, we define

  41. A. A. Deriglazov, Z. Kuznetsova

    For a theory with first and second class constraints, we propose a procedure for conversion of second class constraints based on deformation the structure of local symmetries of the Lagrangian formulation. It does not require extension or reduction of configuration space of the theory. We give examples in which the initial formulation implies a non linear re

  42. Nilanjana Datta, Tony Dorlas

    In this paper we consider the transmission of classical information through a class of quantum channels with long-term memory, which are given by convex combinations of product channels. Hence, the memory of such channels is given by a Markov chain which is aperiodic but not irreducible. We prove the coding theorem and weak converse for this class of channel

  43. Th. Diakonidis, G. J. Gounaris, J. Layssac

    Through the present paper, the code gamgamZZ is presented, which may be used to calculate all possible observables related to the process $γγ\to ZZ$, in either the Standard Model (SM), or the minimal sypersymmetric standard model (MSSM) with real parameters.

  44. Henry N. Chapman, Anton Barty, Michael J. Bogan, Sebastien Boutet

    Theory predicts that with an ultrashort and extremely bright coherent X-ray pulse, a single diffraction pattern may be recorded from a large macromolecule, a virus, or a cell before the sample explodes and turns into a plasma. Here we report the first experimental demonstration of this principle using the FLASH soft X-ray free-electron laser. An intense 25 f

  45. André Goldman

    We prove that the Palm measure of the Ginibre process is obtained by removing a Gaussian distributed point from the process and adding the origin. We obtain also precise formulas describing the law of the typical cell of Ginibre--Voronoi tessellation. We show that near the germs of the cells a more important part of the area is captured in the Ginibre--Voron

  46. Irina Ignatiouk-Robert

    The complete representation of the Martin compactification for reflected random walks on a half-space $\Z^d\times\N$ is obtained. It is shown that the full Martin compactification is in general not homeomorphic to the ``radial'' compactification obtained by Ney and Spitzer for the homogeneous random walks in $\Z^d$ : convergence of a sequence of poin

  47. David Petrosyan, Bernd Schmidt, James R. Anglin, Michael Fleischhauer

    Repulsively interacting particles in a periodic potential can form bound composite objects, whose dissociation is suppressed by a band gap. Nearly pure samples of such repulsively bound pairs of cold atoms -- "dimers" -- have recently been prepared by Winkler et al. [Nature 441, 853 (2006)]. We here derive an effective Hamiltonian for a lattice loade

  48. Anna Karczewska, Carlos Lizama

    In this paper, stochastic Volterra equations driven by cylindrical Wiener process in Hilbert space are investigated. Sufficient conditions for existence of strong solutions are given. The key role is played by convergence of $α$-times resolvent families.

  49. Alexei Borodin, Grigori Olshanski

    We present a solution to a problem suggested by Philippe Biane: We prove that a certain Plancherel-type probability distribution on partitions converges, as partitions get large, to a new determinantal random point process on the set {0,1,2,...} of nonnegative integers. This can be viewed as an edge limit ransition. The limit process is determined by a corre

  50. M. Leclerc

    We present a method for the Hamiltonian formulation of field theories that are based on Lagrangians containing second derivatives. The new feature of our formalism is that all four partial derivatives of the field variables are initially considered as independent fields, in contrast to the conventional Ostrogradski method, where only the velocity is turned i

  51. S. S. Singh

    The direct photon radiation from a hot and slightly strong interacting fireball system of a rich baryon quark-gluon plasma, using the Boltzmann distribution function for the incoming particles and Bose-Einstein distribution for gluon and Fermi-Dirac distribution for quark,antiquark and Boltzmann distribution for gluon are discussed subsequently. The first tw

  52. Sergei Fedotov, Alexander Iomin

    We propose a two-component reaction-transport model for the migration-proliferation dichotomy in the spreading of tumor cells. By using a continuous time random walk (CTRW) we formulate a system of the balance equations for the cancer cells of two phenotypes with random switching between cell proliferation and migration. The transport process is formulated i

  53. Daegene Song

    It is shown that the halting problem cannot be solved consistently in both the Schrodinger and Heisenberg pictures of quantum dynamics. The existence of the halting machine, which is assumed from quantum theory, leads into a contradiction when we consider the case when the observer's reference frame is the system that is to be evolved in both pictures. W

  54. Tom G. Mackay, Akhlesh Lakhtakia

    The perceived lateral position of a transmitted beam, upon propagating through a slab made of homogeneous, isotropic, dielectric material at an oblique angle, can be controlled through varying the velocity of the slab. In particular, by judiciously selecting the slab velocity, the transmitted beam can emerge from the slab with no lateral shift in position. T

  55. Y. G. Ma

    Progress on nuclear liquid gas phase transition (LGPT) or critical behavior has been simply reviewed and some signals of LGPT in heavy ion collisions, especially in NIMROD data, are focused. These signals include the power-law charge distribution, the largest fluctuation of the fragment observables, the nuclear Zipf law, caloric curve and critical exponent a

  56. Junji Jia

    Linearized complex Ginzburg-Landau equation models various physical phenomena and the stability controls of them are important. In this paper, we study the control of the LCGLE with a simultaneously space and time dependent coefficient by transforming it into a complex heat equation. It is shown that under certain conditions on the coefficient functions $a_2

  57. Junji Jia

    In this paper, we study the control of the linear heat equation with a space and time dependent coefficient function by the Dirichlet and Neumann boundary control laws. This equation models the heat diffusion and space, time dependent heat generation in a one dimensional rod. Without control, the system is unstable if the coefficient function is positive and

  58. Christoph Wockel

    In this paper we aim for a generalisation of the Steenrod Approximation Theorem from, concerning a smoothing procedure for sections in smooth locally trivial bundles. The generalisation is that we consider locally trivial smooth bundles with a possibly infinite-dimensional typical fibre. The main result states that a continuous section in a smooth locally tr

  59. Gui-Qiang Chen, Ya-Guang Wang

    Compressible vortex sheets are fundamental waves in entropy solutions to the multidimensional hyperbolic systems of conservation laws. For the Euler equations in 2-D gas dynamics, the classical linearized stability analysis on compressible vortex sheets predicts stability when the Mach number $M>\sqrt{2}$ and instability when $M<\sqrt{2}$; and Artola-Majda&#

  60. Gui-Qiang Chen, Marshall Slemrod, Dehua Wang

    A vanishing viscosity method is formulated for two-dimensional transonic steady irrotational compressible fluid flows with adiabatic constant $γ\in [1,3)$. This formulation allows a family of invariant regions in the phase plane for the corresponding viscous problem, which implies an upper bound uniformly away from cavitation for the viscous approximate velo

  61. Joachim Krieger, Wilhelm Schlag, Daniel Tataru

    We prove the existence of equivariant finite time blow up solutions for the wave map problem from 2+1 dimensions into the 2-sphere. These solutions are the sum of a dynamically rescaled ground-state harmonic map plus a radiation term. The local energy of the latter tends to zero as time approaches blow up time. This is accomplished by first &#34;renormalizin

  62. Bonnie Huggins

    We determine conditions that guarantee that a hyperelliptic or plane curve over a field of characteristic not equal to 2 can be defined over its field of moduli. We also give new examples of curves not definable over their fields of moduli.

  63. Hun Hee Lee

    Orthonormal systems in commutative $L_2$ spaces can be used to classify Banach spaces. When the system is complete and satisfies certain norm condition the unconditionality with respect to the system characterizes Hilbert spaces. As a noncommutative analogue we introduce the notion of unconditionality of operator spaces with respect to orthonormal systems in

  64. Anna Karczewska, Carlos Lizama

    In this paper stochastic Volterra equations admitting exponentially bounded resolvents are studied. After obtaining convergence of resolvents, some properties of stochastic convolutions are given. The paper provides a sufficient condition for a stochastic convolution to be a strong solution to a stochastic Volterra equation.

  65. Hehu Xie

    In this paper, we derive an asymptotic error expansion for the eigenvalue approximations by the lowest order Raviart-Thomas mixed finite element method for the general second order elliptic eigenvalue problems. Extrapolation based on such an expansion is applied to improve the accuracy of the eigenvalue approximations. Furthermore, we also prove the superclo

  66. Victor M. Villalba, Clara Rojas

    We solve the Klein-Gordon equation in the presence of a spatially one-dimensional cusp potential. The scattering solutions are obtained in terms of Whittaker functions and the condition for the existence of transmission resonances is derived. We show the dependence of the zero-reflection condition on the shape of the potential. In the low momentum limit, tra

  67. The BABAR Collaboration, B. Aubert

    We study the initial-state-radiation processes $e^+ e^- \to K^+ K^-π^+π^-γ$ and $e^+ e^- \to K^+ K^-π^0π^0γ$ using an integrated luminosity of 232 fb$^{-1}$ collected at the $Υ(4S)$ mass with the BaBar detector at SLAC. Even though these reactions are dominated by intermediate states with excited kaons, we are able to study for the first time the cross secti

  68. Alexander Unzicker, Karl Fabian

    We present a new test for a possible Mach-Sciama dependence of the Gravitational constant G. According to Ernst Mach (1838-1916), the gravitational interaction depends on the distribution of masses in the universe. A corresponding hypothesis of Sciama (1953) on the gravitational constant, $c^2/G = \sum m_i/r_i$, can be tested since the elliptic earth orbit s

  69. Hannes Hutzelmeyer

    Church&#39;s thesis claims that all effecticely calculable functions are recursive. A shortcoming of the various definitions of recursive functions lies in the fact that it is not a matter of a syntactical check to find out if an entity gives rise to a function. Eight new ideas for a precise setup of arithmetical logic and its metalanguage give the proper en

  70. Gerd Bergmann

    A strong electron-phonon interaction in a metal increases the electron density of states in the vicinity of the Fermi energy dramatically. This phenomenon is called electron-phonon mass enhancement. In this paper the question is investigated whether the mass enhancement can be manipulated in multi-layers of two metals with strong and weak electron-phonon int

  71. Kostya Shundyak, Martin van Hecke, Wim van Saarloos

    We show that in slowly generated 2d packings of frictional spheres, a significant fraction of the friction forces lies at the Coulomb threshold - for small pressure p and friction coefficient mu, about half of the contacts. Interpreting these contacts as constrained leads to a generalized concept of isostaticity, which relates the maximal fraction of fully m

  72. E. W. Bogaart, J. E. M. Haverkort, R. Noetzel

    We demonstrate electromagnetic interaction between distant quantum dots (QDs), as is observed from transient pump-probe differential reflectivity measurements. The QD-exciton lifetime is measured as a function of the probe photon energy and shows a strong resonant behavior with respect to the QD density of states. The observed exciton lifetime spectrum revea

  73. T. P. Yadav, N. K. Mukhopadhyay, R. S. Tiwari, O. N. Srivastava

    The (Co,Ni)Al2O4 is an aluminum transition metals oxide which falls into the category of aluminate spinels. The synthesis of nano-crystalline spinels has been investigated extensively due to their potential applications such as a high-density magnetic recording, microwave devices magnetic fluids, ceramic pigment as well as a heterogeneous catalytic material.

  74. T. P. Yadav, N. K. Mukhopadhyay, R. S. Tiwari, O. N. Srivastava

    In the present investigation the pure elemental powder mixture of Al (70 at%) Ni (15 at %), Cu (15 at %) was mechanically milled in an attritor ball mill for 10, 20, 40, 60, 80 and 100 hours in hexane medium at 400 rpm. The isothermal annealing of 100 h mechanically milled powder has been done at 700 0C for 20, 40 and 60 hours. The mechanically alloyed powde

  75. Luca Salasnich, Boris A. Malomed

    We derive a system of nonpolynomial Schroedinger equations (NPSEs) for one-dimensional wave functions of two components in a binary self-attractive Bose-Einstein condensate loaded in a cigar-shaped trap. The system is obtained by means of the variational approximation, starting from the coupled 3D Gross-Pitaevskii equations and assuming, as usual, the factor

  76. Evgeny N. Bulgakov, Konstantin N. Pichugin, Almas F. Sadreev, Ingrid Rotter

    Using formalism of effective Hamiltonian we consider bound states in continuum (BIC). They are those eigen states of non-hermitian effective Hamiltonian which have real eigen values. It is shown that BICs are orthogonal to open channels of the leads, i.e. disconnected from the continuum. As a result BICs can be superposed to transport solution with arbitrary

  77. Na Young Kim, Patrik Recher, William D. Oliver, Yoshihisa Yamamoto

    We study the electrical transport properties of well-contacted ballistic single-walled carbon nanotubes in a three-terminal configuration at low temperatures. We observe signatures of strong electron-electron interactions: the conductance exhibits bias-voltage-dependent amplitudes of quantum interference oscillation, and both the current noise and Fano facto

  78. Hauke Hinsch, Roger Kouyos, Erwin Frey

    Motor proteins are key players in intracellular transport processes and biological motion. Theoretical modeling of these systems has been achieved by the use of step processes on one-dimensional lattices. After a comprehensive introduction to the total asymmetric exclusion process and some analytical tools, we will give a review on different lines of researc

  79. Naoki Masuda, Norio Konno

    Infectious diseases are practically represented by models with multiple states and complex transition rules corresponding to, for example, birth, death, infection, recovery, disease progression, and quarantine. In addition, networks underlying infection events are often much more complex than described by meanfield equations or regular lattices. In models wi

  80. V. Van Elewyck

    UHE cosmic neutrino interaction with the cosmic neutrino background (CnuB) is expected to produce absorption dips in the UHE neutrino flux at energies above the threshold for Z-boson resonant production. The observation of these dips would constitute an evidence for the existence of the CnuB; they could also be used to determine the value of the relic neutri

  81. Mercedes Lopez-Morales, Jerome A. Orosz, J. Scott Shaw, Lauren Havelka

    We report the discovery of a new detached eclipsing binary known as NSVS01031772 with component masses M_1= 0.5428 +/- 0.0027Msun, M_2= 0.4982 +/- 0.0025Msun, and radii R_1= 0.5260 +/- 0.0028Rsun, R_2= 0.5088 +/- 0.0030Rsun. The system has an orbital period of 0.3681414(3) days and an apparent magnitude V ~ 12.6. The estimated effective temperatures of the s

  82. Giorgio Matt

    General Relativity effects (gravitational redshift, light bending, ...) strongly modify the characteristics of the lines emitted close to the Black Hole in Active Galactic Nuclei and Galactic Black Hole systems. These effects are reviewed and illustrated, with particular emphasis on line emission from the accretion disc. Methods, based on the iron line, to m

  83. Piet Hut

    I provide some background about recent efforts made in modeling dense stellar systems, within the context of the MODEST initiative. During the last four years, we have seen more than fifteen MODEST workshops, with an attendance between twenty and a hundred participants, and topics ranging from very specialized discussions to rather general overviews.

  84. Piet Hut

    At the frontier of most areas in science, computer simulations play a central role. The traditional division of natural science into experimental and theoretical investigations is now completely outdated. Instead, theory, simulation, and experimentation form three equally essential aspects, each with its own unique flavor and challenges. Yet, education in co

  85. Matthias Rempel

    Helioseismology has revealed many details of solar differential rotation and also its time variation, known as torsional oscillations. So far there is no generally accepted theoretical explanation for torsional oscillations, even though a close relation to the solar activity cycle is evident. On the theoretical side non-kinematic dynamo models (including the

  86. B. Harms, O. Micu

    We study a system of electrons moving on a noncommutative plane in the presence of an external magnetic field which is perpendicular to this plane. For generality we assume that the coordinates and the momenta are both noncommutative. We make a transformation from the noncommutative coordinates to a set of commuting coordinates and then we write the Hamilton

  87. Dev Sinha

    In this expository paper we give an elementary, hands-on computation of the homology of the little disks operad, showing that the homology of a $d-fold loop space is a Poisson algebra. One aim is to familiarize a greater audience with Euclidean configuration spaces, using tools accessible to second-year graduate students. We also give a brief introduction to

  88. Stefaan Vaes

    We call a subfactor trivial if it is isomorphic with the obvious inclusion of N into matrices over N. We prove the existence of type II_1 factors M without non-trivial finite index subfactors. Equivalently, every M-M-bimodule with finite coupling constant, both as a left and as a right M-module, is a multiple of L^2(M). Our results rely on the recent work of

  89. C. P. Burgess, C. de Rham, D. Hoover, D. Mason

    We analyze the axially-symmetric scalar perturbations of 6D chiral gauged supergravity compactified on the general warped geometries in the presence of two source branes. We find all of the conical geometries are marginally stable for normalizable perturbations (in disagreement with some recent calculations) and the nonconical for regular perturbations, even

  90. Araceli Bonifant, John Milnor

    We describe the way in which the sign of the Schwarzian derivative for a family of diffeomorphisms of the interval $I$ affects the dynamics of an associated many-to-one skew product map of the cylinder $(\R/\Z)\times I$.

  91. Alex Giacomini, Ricardo Troncoso, Steven Willison

    The locally supersymmetric extension of the most general gravity theory in three dimensions leading to first order field equations for the vielbein and the spin connection is constructed. Apart from the Einstein-Hilbert term with cosmological constant, the gravitational sector contains the Lorentz-Chern-Simons form and a term involving the torsion each with

  92. Bohdan Grzadkowski, Jose Wudka

    We discuss several aspects of higher dimensional models that contain bulk gauge and fermion fields only. In particular we argue that non-standard boundary conditions involving charge-conjugate fermion fields offer attractive model building possibilities. We also discuss a no-go theorem for 5-dimensional models which severely limits their phenomenological rel

  93. Zhaoming Ma

    We modify the public PM code developed by Anatoly Klypin and Jon Holtzman to simulate cosmology with arbitrary initial power spectrum and equation of state of dark energy. With this tool in hand, we perform the following studies on the matter power spectrum. With an artificial sharp peak at k~0.2 h/Mpc in the initial power spectrum, we find that the position

  94. Michel L. Lapidus, Jacques Levy Vehel, John A. Rock

    For a Borel measure on the unit interval and a sequence of scales that tend to zero, we define a one-parameter family of zeta functions called multifractal zeta functions. These functions are a first attempt to associate a zeta function to certain multifractal measures. However, we primarily show that they associate a new zeta function, the topological zeta

  95. Mark C. Neyrinck, István Szapudi

    We investigate the cosmological Fisher information in the non-linear dark-matter power spectrum in the context of the halo model. We find that there is a plateau in information content on translinear scales which is generic to all cosmological parameters we tried. There is a rise in information on smaller scales, but we find that it is quite degenerate among

  96. Youjin Deng, Timothy M. Garoni, Alan D. Sokal

    We present Monte Carlo simulations of the spanning-forest model (q \to 0 limit of the ferromagnetic Potts model) in spatial dimensions d=3,4,5. We show that, in contrast to the two-dimensional case, the model has a &#34;ferromagnetic&#34; second-order phase transition at a finite positive value w_c. We present numerical estimates of w_c and of the thermal an

  97. JLQCD Collaboration, T. Ishikawa, S. Aoki, M. Fukugita

    We present a summary of results of the joint CP-PACS and JLQCD project toward a 2+1 flavor full QCD simulation with the O(a)-improved Wilson quark formalism and the Iwasaki gauge action. Configurations were generated during 2002-2005 at three lattice spacings, a~0.076, 0.100 and 0.122 fm, keeping the physical volume constant at (2.0fm)^3. Up and down quark m

  98. David Seery, James E. Lidsey, Martin S. Sloth

    We calculate the trispectrum of the primordial curvature perturbation generated by an epoch of slow-roll inflation in the early universe, and demonstrate that the non-gaussian signature imprinted at horizon crossing is unobservably small, of order tau_NL < r/50, where r < 1 is the tensor-to-scalar ratio. Therefore any primordial non-gaussianity observed in f

  99. Soren Galatius

    Homology of the group Aut(F_n) of automorphisms of a free group on n generators is known to be independent of n in a certain stable range. Using tools from homotopy theory, we prove that in this range it agrees with homology of symmetric groups. In particular, Aut(F_n) has no stable rational homology, settling a conjecture of Hatcher and Vogtmann.

  100. W. F. Wall

    An improved formulation for the X-factor is proposed. The statement that the velocity-integrated radiation temperature of the $\COone$ line, $I(\CO)$, ``counts'' optically thick clumps is quantified using the formalism of \citet{Martin84} for line emission in a clumpy cloud. Adopting the simplifying assumptions of thermalized $\COone$ line emission and isoth