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April 2008 arXiv papers — page 25

Showing 2,4012,500 of 4,892 papers

  1. F. Jansson, S. D. Baranovskii, F. Gebhard, R. Österbacka

    For hopping transport in disordered materials, the mobility of charge carriers is strongly dependent on temperature and the electric field. Our numerical study shows that both the energy distribution and the mobility of charge carriers in systems with a Gaussian density of states, such as organic disordered semiconductors, can be described by a single parame

  2. H. Beuther, H. D. Nissen

    The enigmatic outflows of the Orion-KL region have raised discussions about their potential driving sources for several decades. Here, we present C18O(2-1) observations combined from the Submillimeter Array and the IRAM30m telescope. The molecular gas is associated on large scales with the famous northwest-southeast high-velocity outflow whereas the high-vel

  3. Emily S. C. Ching, H. Guo, W. C. Cheng

    Different scaling behavior has been reported in various shell models proposed for turbulent thermal convection. In this paper, we show that buoyancy is not always relevant to the statistical properties of these shell models even though there is an explicit coupling between velocity and temperature in the equations of motion. When buoyancy is relevant (irrele

  4. A. F. Al Alam, S. F. Matar, N. Ouaini, M. Nakhl

    The electronic and magnetic structures of $ {\rm ScFe_2} $ and of its dihydride $ {\rm ScFe_2H_2} $ are self-consistently calculated within the density functional theory (DFT) using the all electron augmented spherical wave (ASW) method with the local spin density approximation (LSDA) for treating effects of exchange and correlation. The results of the enhan

  5. Mohammad Mehrafarin, Nima Pourtolami

    Recently, by analyzing the measurement data of Nikuradze, it has been proposed (N. Goldenfeld, Phys. Rev. Lett. {\bf{96}}, 044503, 2006) that the friction factor, $f$, of rough pipe flow obeys a scaling law in the turbulent regime. Here, we provide a phenomenological scaling argument to explain this law and demonstrate how intermittency modifies the scaling

  6. Aleksander Wojdyga

    This paper presents simple, syntactic strong normalization proofs for the simply-typed lambda-calculus and the polymorphic lambda-calculus (system F) with the full set of logical connectives, and all the permutative reductions. The normalization proofs use translations of terms and types to systems, for which strong normalization property is known.

  7. Emily S. C. Ching, H. Guo, T. S. Lo

    A major challenge in turbulence research is to understand from first principles the origin of anomalous scaling of the velocity fluctuations in high-Reynolds-number turbulent flows. One important idea was proposed by Kolmogorov [J. Fluid Mech. {\bf 13}, 82 (1962)], which attributes the anomaly to the variations of the locally averaged energy dissipation rate

  8. Jiansong Deng, Falai Chen, Liangbing Jin

    This paper discusses the dimensions of the spline spaces over T-meshes with lower degree. Two new concepts are proposed: extension of T-meshes and spline spaces with homogeneous boundary conditions. In the dimension analysis, the key strategy is linear space embedding with the operator of mixed partial derivative. The dimension of the original space equals t

  9. Emily S. C. Ching, T. C. Ko

    An interesting question in turbulent convection is how the heat transport depends on the strength of thermal forcing in the limit of very large thermal forcing. Kraichnan predicted [Phys. Fluids {\bf 5}, 1374 (1962)] that the heat transport measured by the Nusselt number (Nu) would depend on the strength of thermal forcing measured by the Rayleigh number (Ra

  10. Wei Ren, Fuming Xu, Jian Wang

    We report the investigation of the dynamic conductance fluctuation of disordered mesoscopic conductors including 1D, 2D and quantum dot systems. Our numerical results show that in the quasi-ballistic regime the average emittance is negative indicating the expected inductive-like behavior. However, in the diffusive and localized regime, the average emittance

  11. J. A. Oller, L. Roca, C. Schat

    We report on a dispersion relation for the γγ\to (ππ)_I S-wave in isospin I emphasizing the low energy region. The f_0(980) signal that emerges in γγ\to ππis also discussed. Our results could be used to distinguish between different ππisoscalar S-wave parameterizations. We also calculate the width of the σresonance to γγand obtain the value Γ(σ\toγγ)=(1.68\p

  12. R. Sato, J. Kataoka, T. Takahashi, G. M. Madejski

    We observed the TeV blazar 1ES 1218+304 with the X-ray astronomy satellite Suzaku in May 2006. At the beginning of the two-day continuous observation, we detected a large flare in which the 5-10 keV flux changed by a factor of ~2 on a timescale of 5x10^4 s. During the flare, the increase in the hard X-ray flux clearly lagged behind that observed in the soft

  13. Jean-Christophe Breton, Ivan Nourdin

    Let $q\geq 2$ be a positive integer, $B$ be a fractional Brownian motion with Hurst index $H\in(0,1)$, $Z$ be an Hermite random variable of index $q$, and $H_q$ denote the Hermite polynomial having degree $q$. For any $n\geq 1$, set $V_n=\sum_{k=0}^{n-1} H_q(B_{k+1}-B_k)$. The aim of the current paper is to derive, in the case when the Hurst index verifies $

  14. Diego F. Torres, Ana Y. Rodriguez Marrero, Elsa de Cea del Pozo

    We present a theoretical model that explains the high energy phenomenology of the neighborhood of SNR IC 443, as observed with the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescope and the Energetic Gamma-Ray Experiment Telescope (EGRET). We interpret MAGIC J0616+225 as delayed TeV emission of cosmic-rays diffusing from IC 443 and interacting with

  15. Annamaria Kiss, Yoshio Kuramoto

    By phenomenological Landau analysis, it is shown that a scalar order parameter with the point-group symmetry $Γ_{1g}$ explains most properties associated with the phase transition in PrFe$_4$P$_{12}$ at 6.5 K. The scalar-order model reproduces magnetic and elastic properties in PrFe$_4$P$_{12}$ consistently such as (i) the anomaly of the magnetic susceptibil

  16. Annamaria Kiss, Yoshio Kuramoto

    Phenomenological Landau analysis shows that the properties of ordered phases in some skutterudites are consistently accounted for by a scalar order parameter which preserves the cubic symmetry, even in the ordered phase. A universal value is found for the anisotropy ratio of the transition temperature in a magnetic field, homogeneous magnetization, and induc

  17. Takehisa Fujita

    The quantum field theory of gravitation is constructed in terms of Lagrangian density of Dirac fields which couple to the electromagnetic field $A_μ$ as well as the gravitational field $\cal G$. The gravity appears in the mass term as $ m(1+g {\cal G}) \barψψ$ with the coupling constant of $g$. In addition to the gravitational force between fermions, the ele

  18. Chang-shui Yu, X. X. Yi, He-shan Song, D. Mei

    We have proposed a simple scheme to entangle two distant qutrits trapped in separate optical cavities. The quantum information of each qutrit is skillfully encoded on the degenerate ground states of a pair of atoms, hence the entanglement between them is relatively stable against spontaneous emission. In Lamb-Dicke limits, it is not necessary to require coin

  19. T. Kuroda, M. Abbarchi, T. Mano, K. Watanabe

    We report on photon coincidence measurement in a single GaAs self-assembled quantum dot (QD) using a pulsed excitation light source. At low excitation, when a neutral exciton line was present in the photoluminescence (PL) spectrum, we observed nearly perfect single photon emission from an isolated QD at 670 nm wavelength. For higher excitation, multiple PL l

  20. A. Vershik

    We consider the sequence of the hyperspheres $M_{n,r}$ i.e. the homogeneous transitive spaces - of the Cartan subgroup $SDiag(n,\Bbb R)$ of the group $SL(n,\Bbb R), n=1 ...$, and studied the normalized limit of the corresponding sequence of the invariant measures $m_n$ on those spaces. In the case of compact groups and homogeneous spaces, as example - for cl

  21. Reiho Sakamoto

    We review reformulation of the map from tensor product of crystals to the rigged configurations in terms of the energy function of affine crystals. Especially, we give intuitive picture of the inverse scattering formalism for the periodic box-ball systems formulated by Kuniba-Takagi-Takenouchi (arXiv:math/0602481v2).

  22. T. Matsuki, T. Morii, K. Sudoh

    The semi-relativistic quark potential model is surprisingly powerful for heavy-light systems if the bound state equation is treated correctly using 1/m_Q expansion with heavy quark mass m_Q. We elucidate the reasons why our semi-relativistic model succeeds in predicting and reproducing all the mass spectra of heavy-light systems so far reported, D/D_s/B/B_s,

  23. I. P. McCulloch

    I revisit the infinite-size variant of the Density Matrix Renormalization Group (iDMRG) algorithm for obtaining a fixed-point translationally invariant matrix product wavefunction in the context of one-dimensional quantum systems. A crucial ingredient of this algorithm is an efficient transformation for obtaining the matrix elements of the wavefunction as th

  24. E. R. Cazaroto, F. Carvalho, V. P. Goncalves, F. S. Navarra

    A systematic determination of the gluon distribution is of fundamental interest in understanding the parton structure of nuclei and the QCD dynamics. Currently, the behavior of this distribution at small $x$ (high energy) is completely undefined. In this paper we analyze the possibility of constraining the nuclear effects present in $xg^A$ using the inclusiv

  25. Shun-Jen Cheng, Weiqiang Wang

    We examine in detail the Jacobi-Trudi characters over the ortho-symplectic Lie superalgebras spo(2|2m+1) and spo(2n|3). We furthermore relate them to Serganova's notion of Euler characters.

  26. B. Hiller, A. A. Osipov, J. Moreira, A. H. Blin

    The thermodynamic potential and thermal dependence of low lying mass spectra of scalars and pseudoscalars are evaluated in a generalized Nambu -- Jona-Lasinio model, which incorporates eight-quark interactions. These are necessary to stabilize the scalar effective potential for the light and strange quark flavors, which would be otherwise unbounded from belo

  27. David E. Kaplan, Matthew D. Schwartz

    Using recently developed techniques for computing event shapes with Soft-Collinear Effective Theory, LEP event shape data is used to derive strong model-independent bounds on new colored particles. In the effective field theory computation, colored particles contribute in loops not only to the running of alpha_s but also to the running of hard, jet and soft

  28. J. M. Zaldivar, F. S. Bacelar, S. Dueri, D. Marinov

    Pristine coastal shallow systems are usually dominated by extensive meadows of seagrass species, which are assumed to take advantage of nutrient supply from sediment. An increasing nutrient input is thought to favour phytoplankton, epiphytic microalgae, as well as opportunistic ephemeral macroalgae that coexist with seagrasses. The primary cause of shifts an

  29. Suman Bhattacharya, Arthur Kosowsky

    Galaxy cluster surveys compiled via the Sunyaev-Zeldovich Effect have the potential to place strong constraints on cosmology, and in particular the nature of dark energy. Here we consider cluster velocity surveys using kinetic Sunyaev-Zeldovich measurements. Cluster velocities closely trace the large-scale velocity field independent of cluster mass; we demon

  30. Erik van Erp

    We present a new solution to the index problem for hypoelliptic operators in the Heisenberg calculus on contact manifolds, by constructing the appropriate topological K-theory cocycle for such operators. Its Chern character gives a cohomology class to which the Atiyah-Singer index formula can be applied. Such a K-cocycle has already been constructed by Boute

  31. Raji Heyrovska

    Recently, the bond lengths of the molecular components of nucleic acids and of caffeine and related molecules were shown to be sums of the appropriate covalent radii of the adjacent atoms. Thus, each atom was shown to have its specific contribution to the bond length. This enabled establishing their atomic structures for the first time. In this work, the kno

  32. L. Mattsson, R. Wahlin, S. Höfner, K. Eriksson

    We argue that the energy injection of pulsations may be of greater importance to the mass-loss rate of AGB stars than metallicity, and that the mass-loss trend with metallicity is not as simple as sometimes assumed. Using our detailed radiation hydrodynamical models that include dust formation, we illustrate the effects of pulsation energy on wind properties

  33. S. A. Merkulov

    Using technique of wheeled props we establish a correspondence between the homotopy theory of unimodular Lie 1-bialgebras and the famous Batalin-Vilkovisky formalism. Solutions of the so called quantum master equation satisfying certain boundary conditions are proven to be in 1-1 correspondence with representations of a wheeled dg prop which, on the one hand

  34. Ian Swanson

    The spacetime physics of bulk closed string tachyon condensation is studied at the level of a two-derivative effective action. We derive the unique perturbative tachyon potential consistent with a full class of linearized tachyonic deformations of supercritical string theory. The solutions of interest deform a general linear dilaton background by the inserti

  35. Andre Chatzistamatiou

    If $X_λ$ is a smooth member of the Dwork family over a perfect field $k$, and $Y_λ$ is its mirror variety, then the motives of $X_λ$ and $Y_λ$ are equal up to motives that are in coniveau $\geq 1$. If $k$ is a finite field, this provides a motivic explanation for Wan's congruence between the zeta functions of $X_λ$ and $Y_λ$.

  36. Wei Li

    We present a systematic study of two-particle angular correlations in p+p, Cu+Cu and Au+Au collisions over a broad range of pseudorapidity and azimuthal angle. The PHOBOS detector has a uniquely large angular coverage for inclusive charged particles, which allows for the study of correlations on both long- and short-range scales. A complex two-dimensional co

  37. Alexander Schönhuth

    Entropy rate is a real valued functional on the space of discrete random sources which lacks a closed formula even for subclasses of sources which have intuitive parameterizations. A good way to overcome this problem is to examine its analytic properties relative to some reasonable topology. A canonical choice of a topology is that of the norm of total varia

  38. Gabriella De Lucia, Amina Helmi

    We use a series of high-resolution simulations of a `Milky-Way' halo coupled to semi-analytic methods to study the formation of our own Galaxy and of its stellar halo. The physical properties of our model Milky Way, as well as the age and metallicity distribution of stars in the different components, are in relatively good agreement with observational me

  39. Timur R. Seifullin

    The notion of a root functional of a system of polynomials or ideal of polynomials is a generalization of the notion of a root, in particular, for a multiple root. A root functional is a linear functional that is defined on a polynomial ring and annuls the ideal of polynomials. A bounded root functional is a functional that annuls d-th component of the ideal

  40. N. Regnault, M. O. Goerbig, Th. Jolicoeur

    We propose a scheme to construct the most prominent Abelian and non-Abelian fractional quantum Hall states from K-component Halperin wave functions. In order to account for a one-component quantum Hall system, these SU(K) colors are distributed over all particles by an appropriate symmetrization. Numerical calculations corroborate the picture that the propos

  41. Elena R. Loubenets

    We consistently formalize the probabilistic description of multipartite joint measurements performed on systems of any nature. This allows us: (1) to specify in probabilistic terms the difference between nonsignaling, the Einstein- Podolsky-Rosen (EPR) locality and Bell's locality; (2) to introduce the notion of an LHV model for an S_{1}x...xS_{N}-settin

  42. S. K. Samaddar, J. N. De, X. Vinas, M. Centelles

    The density and excitation energy dependence of symmetry energy and symmetry free energy for finite nuclei are calculated microscopically in a microcanonical framework taking into account thermal and expansion effects. A finite-range momentum and density dependent two-body effective interaction is employed for this purpose. The role of mass, isospin and equa

  43. Lorenzo Bertini, Claudio Landim, Mustapha Mourragui

    We consider the weakly asymmetric exclusion process on a bounded interval with particle reservoirs at the endpoints. The hydrodynamic limit for the empirical density, obtained in the diffusive scaling, is given by the viscous Burgers equation with Dirichlet boundary conditions. We prove the associated dynamical large deviations principle.

  44. Patrizia Ferrero, Sylvio Klose, David Alexander Kann, Sandra Savaglio

    The long and relatively faint gamma-ray burst GRB 060605 detected by \emph{Swift}/BAT lasted about 20 sec. Its afterglow could be observed with \emph{Swift}/XRT for nearly 1 day, while \emph{Swift}/UVOT could detect the afterglow during the first 6 hours after the event. Here, we report on integral field spectroscopy of its afterglow performed with PMAS/PPak

  45. Michael C. Mackey, Marta Tyran-Kaminska

    A new sufficient condition is proved for the existence of stochastic semigroups generated by the sum of two unbounded operators. It is applied to one-dimensional piecewise deterministic Markov processes, where we also discuss the existence of a unique stationary density and give sufficient conditions for asymptotic stability.

  46. E. Iltan

    We predict the contribution of scalar unparticle to the branching ratios of the lepton flavor conserving Z -> l^+ l^- decays and we study the discrepancy between the experimental and the QED corrected standard model branching ratios. We observe that these decays are sensitive to the unparticle scaling dimension d_u for its small values, especially for heavy

  47. Clara I. Osorio, Alejandra Valencia, Juan P. Torres

    In most configurations aimed at generating entangled photons based on spontaneous parametric down conversion (SPDC), the generated pairs of photons are required to be entangled in only one degree of freedom. Any distinguishing information coming from the other degrees of freedom that characterize the photon should be suppressed to avoid correlations with the

  48. Charles-Michel Marle

    A Lie algebroid over a manifold is a vector bundle over that manifold whose properties are very similar to those of a tangent bundle. Its dual bundle has properties very similar to those of a cotangent bundle: in the graded algebra of sections of its external powers, one can define an operator similar to the exterior derivative. We present in this paper the

  49. S. Tsonis, P. Kotetes, G. Varelogiannis, P. B. Littlewood

    We have studied systematically the influence of particle-hole symmetric and asymmetric kinetic terms on the ordered phases that we may observe competing or coexisting in a tetragonal system. We show that there are precise patterns of triplets of ordered phases that are accessible (i.e. it is impossible to observe two of them without the third one). We found

  50. H. L. Morrison, A. Helmi, J. Sun, P. Liu

    Using a sample of 248 metal-poor stars (RR Lyraes, red giants and RHB stars) which is remarkable for the accuracy of its 6-D kinematical data, we find a new component for the local halo which has an axial ratio c/a ~ 0.2, a similar flattening to the thick disk. It has a small prograde rotation but is supported by velocity anisotropy, and contains more interm

  51. Eyal Feigenbaum, Meir Orenstein

    Nano particle-plasmons are attributed to quasi-static oscillation with no wave propagation due to their subwavelength size. However, when located within a band-gap medium (even in air if the particle is small enough), the particle interfaces are acting as wave-mirrors, incurring small negative retardation. The latter when compensated by a respective (short)

  52. Scott Funkhouser

    Five fundamental scales of mass follow from holographic limitations, a self-similar law for angular momentum and the basic scaling laws for a fractal universe with dimension 2. The five scales correspond to the observable universe, clusters, galaxies, stars and the nucleon. The fundamental scales form naturally a self-similar hierarchy, generating new relati

  53. P. Bielewicz, A. Riazuelo

    We study a multipole vector-based decomposition of cosmic microwave background (CMB) data in order to search for signatures of a multiconnected topology of the universe. Using 10^6 simulated maps, we analyse the multipole vector distribution on the sky for the lowest order multipoles together with the probability distribution function of statistics based on

  54. Michael Batty, Rui Carvalho, Andy Hudson-Smith, Richard Milton

    Many aggregate distributions of urban activities such as city sizes reveal scaling but hardly any work exists on the properties of spatial distributions within individual cities, notwithstanding considerable knowledge about their fractal structure. We redress this here by examining scaling relationships in a world city using data on the geometric properties

  55. Donatello W. Materassi, Giacomo W. Innocenti

    The paper deals with the problem of reconstructing the topological structure of a network of dynamical systems. A distance function is defined in order to evaluate the "closeness" of two processes and a few useful mathematical properties are derived. Theoretical results to guarantee the correctness of the identification procedure for networked linear

  56. Carolina Brito, Matthieu Wyart

    We estimate numerically the normal modes of the free energy in a glass of hard discs. We observe that, near the glass transition or after a rapid quench deep in the glass phase, the density of states (i) is characteristic of a marginally stable structure, in particular it di splays a frequency scale $ω^*\sim p^{1/2}$, where $p$ is the pressure and (ii) gives

  57. Lawrence H. Friedman

    Strained coherent heteroepitaxy of III-V semiconductor films such as In$_x$Ga$_{1-x}$As/GaAs has potential for electronic and optoelectronic applications such as high density logic, quantum computing architectures, laser diodes, and other optoelectronic devices. Crystal symmetry can have a large effect on the morphology of these films and their spatial order

  58. Francois Laroussinie, Nicolas Markey, Ghassan Oreiby

    ATL is a temporal logic geared towards the specification and verification of properties in multi-agents systems. It allows to reason on the existence of strategies for coalitions of agents in order to enforce a given property. In this paper, we first precisely characterize the complexity of ATL model-checking over Alternating Transition Systems and Concurren

  59. Jean-Marie Aubry, Cristina Butucea, Katia Méziani

    In the framework of noisy quantum homodyne tomography with efficiency parameter $0 < η\leq 1$, we propose two estimators of a quantum state whose density matrix elements $ρ_{m,n}$ decrease like $e^{-B(m+n)^{r/ 2}}$, for fixed known $B>0$ and $0<r\leq 2$. The first procedure estimates the matrix coefficients by a projection method on the pattern functions (th

  60. Xiao Guo, Yu Zhang

    We find a larger class of virtually fibred classic Montesinos links of type $\widetilde{SL_2}$, extending a result of Agol, Boyer and Zhang.

  61. Eugene Strahov

    We consider the problem of computation of the correlation functions for the z-measures with the deformation (Jack) parameters 2 or 1/2. Such measures on partitions are originated from the representation theory of the infinite symmetric group, and in many ways are similar to the ensembles of Random Matrix Theory of $β=4$ or $β=1$ symmetry types. For a certain

  62. Philippe Biane, Philippe Bougerol, Neil O&#39;Connell

    We introduce a notion of continuous crystal analogous, for general Coxeter groups, to the combinatorial crystals introduced by Kashiwara in representation theory of Lie algebras. We use a generalization of the Littelmann path model to show the existence of the crystals, and study an associated Duistermaat-Heckman measure, which we interpret in terms of Brown

  63. Frédéric Déglise

    We define and study Gysin morphisms on mixed motives over a perfect field. Our construction extends the case of closed immersions, already known from results of Voevodsky, to arbitrary projective morphisms. We prove several classical formulas in this context, such as the projection and excess intersection formulas, and some more original ones involving resid

  64. Tommy Anderberg

    I informally review the Higgs mechanism, focusing on fundamental aspects which should be common knowledge but apparently are not, explain why your understanding of gauge symmetry breaking is a decreasing function of your reliance on the unitary gauge, and discuss some implications for cosmology (domains, dark energy, CMB cold spot).

  65. I. M. Vellekoop, A. P. Mosk

    We experimentally demonstrate increased transmission of light through strongly scattering materials. Wavefront shaping is used to selectively couple light to the open transport channels in the material, resulting in an increase of up to 44% in the total transmission. The results for each of several hundreds of experimental runs are in excellent quantitative

  66. H. Obuse, A. R. Subramaniam, A. Furusaki, I. A. Gruzberg

    We study multifractal spectra of critical wave functions at the integer quantum Hall plateau transition using the Chalker-Coddington network model. Our numerical results provide important new constraints which any critical theory for the transition will have to satisfy. We find a non-parabolic multifractal spectrum and we further determine the ratio of bound

  67. Daniel Boer

    A collection of results is presented relevant for the analysis of azimuthal asymmetries in inclusive two-hadron production at BELLE. The aim of this overview is to provide theoretical ingredients necessary to extract the Collins effect fragmentation function. The latter arises within the Collins-Soper factorization formalism, which describes both the transve

  68. K. De Commer

    In this article, we investigate the notion of a Galois object for a locally compact quantum group M. Such an object consists of a von Neumann algebra N equipped with an ergodic integrable coaction of M on N, such that the crossed product is a type I factor. We show how to construct from such a coaction a new locally compact quantum group P, which we call the

  69. J. M. P. Carmelo

    The Hubbard model on a square lattice is one of the most studied condensed-matter quantum problems.Here we find evidence that for intermediate $U/4t$ values and a hole-concentration range $x\in (x_c,x_*)$ the ground state of the Hubbard model on the square lattice perturbed by weak three-dimensional (3D) uniaxial anisotropy has long-range d-wave superconduct

  70. J. M. P. Carmelo

    The momentum bands, energy dispersions, and velocities of the charge $c$ fermions and spin-neutral two-spinon $s1$ fermions of a square-lattice quantum liquid referring to the Hubbard model on such a lattice of edge length $L$ in the one- and two-electron subspace are studied. The model involves the effective nearest-neighbor integral $t$ and on-site repulsi

  71. J. M. P. Carmelo

    In this paper the spin configurations of the ground state and one- and two-electron excited states of the Hubbard model on the square lattice are studied. We profit from a general rotated-electron description, which is consistent with the model global $SO(3)\times SO(3)\times U(1)$ symmetry. For rotated electrons, doubly and single occupancy are good quantum

  72. J. M. P. Carmelo, M. J. Sampaio

    In this paper a description of the Hubbard model on the square lattice with nearest-neighbor transfer integral $t$, on-site repulsion $U$, and $N_a^2\gg 1$ sites consistent with its exact global $SO(3)\times SO(3)\times U(1)$ symmetry is constructed. Our studies profit from the interplay of that recently found global symmetry of the model on any bipartite la

  73. J. M. P. Carmelo

    Here we use a description of the electronic correlations contained in the Hubbard model on the square-lattice perturbed by very weak three-dimensional uniaxial anisotropy in terms of the residual interactions of charge $c$ fermions and spin-neutral composite two-spinon $s1$ fermions. Excellent quantitative agreement with the anisotropic linear-$ω$ one-electr

  74. R. M. Gomes, W. B. Cardoso, A. T. Avelar, B. Baseia

    In this paper we propose a scheme to implement a quantum teleportation based on the current experimental design [Nature (London) 431, 162 (2004); ibid 445, 515 (2007)] in which superconducting charge qubits are capacitively coupled to a single high-Q superconducting coplanar resonator. As advantage of this architecture, it permits the use of multiqubit gates

  75. V. M. Khatsymovsky

    We consider Regge calculus in the representation in terms of area tensors and self- and antiselfdual connections generalised to the case of Holst action that is standard Einstein action in the tetrad-connection variables plus topological (on equations of motion for connections) term with coefficient $1/γ$, $γ$ is Barbero-Immirzi parameter. The quantum measur

  76. C. Destri, H. J. de Vega, N. G. Sanchez

    Generically,the classical evolution of the inflaton has a brief fast roll stage that precedes the slow roll regime. The fast roll stage leads to a purely attractive potential for the curvature and tensor perturbations (this potential is purely repulsive in slowroll). This attractive potential depresses the CMB quadrupole moment for the curvature and B-mode s

  77. Gernot Schaller, Tobias Brandes

    We compare different quantum Master equations for the time evolution of the reduced density matrix. The widely applied secular approximation (rotating wave approximation) applied in combination with the Born-Markov approximation generates a Lindblad type master equation ensuring for completely positive and stable evolution and is typically well applicable fo

  78. Attilio Cucchieri, Tereza Mendes

    We present rigorous upper and lower bounds for the momentum-space ghost propagator G(p) of Yang-Mills theories in terms of the smallest nonzero eigenvalue (and of the corresponding eigenvector) of the Faddeev-Popov matrix. We apply our analysis to data from simulations of SU(2) lattice gauge theory in Landau gauge, using the largest lattice sizes to date. Ou

  79. A. Bialas, A. Bzdak, R. Peschanski

    Exploiting the idea that the fast partons of an energetic projectile can be treated as sources of color radiation interpreted as wee partons, it is shown that the recently observed property of extended limiting fragmentation implies a scaling law for the rapidity distribution of fast partons. This leads to a picture of a self-similar process where, for fixed

  80. M. I. Katsnelson, F. Guinea

    We study the transport through evanescent waves in graphene quantum dots of different geometries. The transmission is suppressed when the leads are attached to edges of the same majority sublattice. Otherwise, the transmission depends exponentially on the distance between leads in rectangular dots, and as a power law in circular dots. The transmission throug

  81. T. Tao, V. Vu

    We show that the permanent of an $n \times n$ matrix with iid Bernoulli entries $\pm 1$ is of magnitude $n^{({1/2}+o(1))n}$ with probability $1-o(1)$. In particular, it is almost surely non-zero.

  82. Wojciech Bruzda, Valerio Cappellini, Hans-Jürgen Sommers, Karol Życzkowski

    We define a natural ensemble of trace preserving, completely positive quantum maps and present algorithms to generate them at random. Spectral properties of the superoperator Phi associated with a given quantum map are investigated and a quantum analogue of the Frobenius-Perron theorem is proved. We derive a general formula for the density of eigenvalues of

  83. Benoit Kloeckner

    Let $\rho_0$ be an action of a Lie group on a manifold with boundary that is transitive on the interior. We study the set of actions that are topologically conjugate to $\rho_0$, up to smooth or analytic change of coordinates. We show that in many cases, including the compactifications of negatively curved symmetric spaces, this set is infinite.

  84. Shuo Cheng, Junli Li, Cong-Feng Qiao

    We develop a novel method in classifying the multipartite entanglement state of $2\times N\times N$ under stochastic local operation and classical communication. In this method, all inequivalent classes of true entangled state can be assorted directly without knowing the classification information of lower dimension ones for any given dimension $N$. It also

  85. A. V. Smirnov, A. A. Krizhanovsky

    In this paper we present a profile-based approach to information filtering by an analysis of the content of text documents. The Wikipedia index database is created and used to automatically generate the user profile from the user document collection. The problem-oriented Wikipedia subcorpora are created (using knowledge extracted from the user profile) for e

  86. C. Bahadoran, H. Guiol, K. Ravishankar, E. Saada

    We prove almost sure Euler hydrodynamics for a large class of attractive particle systems on $\Z$ starting from an arbitrary initial profile. We generalize earlier works by Seppäläinen (1999) and Andjel et al. (2004). Our constructive approach requires new ideas since the subadditive ergodic theorem (central to previous works) is no longer effective in our s

  87. M. Tahir, K. Sabeeh

    Collective excitations spectrum of Dirac electrons in mono and bilayer graphene in the presence of a uniform magnetic field is investigated. Analytical results for inter-Landau band plasmon spectrum within the self-consistent-field approach are obtained. SdH type oscillations that are a monotonic function of the magnetic field are observed in the plasmon spe

  88. Z. Borjan, P. J. Upton

    Extended de Gennes-Fisher (EdGF) local-functional method has been applied to the thermodynamic Casimir effect {\it away} from the critical point for systems in the Ising universality class confined between parallel plane plates with symmetric boundary conditions (denoted $(ab)=(++)$). Results on the universal scaling functions of the Casimir force $W_{++}(y)

  89. Dmitry I. Podolsky, Jaydeep Majumder, Niko Jokela

    Disorder on the string theory landscape may significantly affect dynamics of eternal inflation leading to the possibility for some vacua on the landscape to become dynamically preferable over others. We systematically study effects of a generic disorder on the landscape starting by identifying a sector with built-in disorder -- a set of de Sitter vacua corre

  90. M. Baldo, G. F. Burgio, P. Castorina, S. Plumari

    We explore the relevance of confinement in quark matter models for the possible quark core of neutron stars. For the quark phase, we adopt the equation of state (EoS) derived with the Field Correlator Method, extended to the zero temperature limit. For the hadronic phase, we use the microscopic Brueckner-Hartree-Fock many-body theory. We find that the curren

  91. R. F. Efendiev

    The inverse problem for the differential operator pencil with complex periodic potential and discontinuous coefficients on the axis is studied. Main characteristics of the fundamental solutions are investigated, the spectrum of the operator is studied. We give formulation of the inverse problem, prove a uniqueness theorem and provide a constructive procedure

  92. Primoz Peterlin, Gasper Jaklic, Tomaz Pisanski

    A technique for determining the permeability of a phospholipid membrane on a single giant unilamellar vesicle (GUV) is described, which complements the existing methods utilizing either a planar black lipid membrane or sub-micrometre-sized liposomes. A single GUV is transferred using a micropipette from a solution of a nonpermeable solute into an iso-osmolar

  93. Vyacheslav M. Abramov

    Let $\mathcal{G}(\frak{g}_1,\frak{g}_2)$ be the class of all probability distribution functions of positive random variables having the given first two moments $\frak{g}_1$ and $\frak{g}_2$. Let $G_1(x)$ and $G_2(x)$ be two probability distribution functions of this class satisfying the condition $|G_1(x)-G_2(x)|<ε$ for some small positive value $ε$ and let

  94. P. Zhang, J. Zhou, M. W. Wu

    Multi-valley spin relaxation in $n$-type GaAs quantum wells with in-plane electric field is investigated at high temperature by means of kinetic spin Bloch equation approach. The spin relaxation time first increases and then decreases with electric field, especially when the temperature is relatively low. We show that $L$ valleys play the role of a ``drain&#

  95. Azhar Iqbal, Taksu Cheon, Derek Abbott

    This paper extends our probabilistic framework for two-player quantum games to the mutliplayer case, while giving a unified perspective for both classical and quantum games. Considering joint probabilities in the standard Einstein-Podolsky-Rosen-Bohm (EPR-Bohm) setting for three observers, we use this setting in order to play general three-player non-coopera

  96. Ming-Hsuan Kang, Wen-Ching Winnie Li

    In this paper we obtain a closed form expression of the zeta function $Z(X_Γ, u)$ of a finite quotient $X_Γ= Γ\backslash PGL_3(F)/PGL_3(O_F)$ of the Bruhat-Tits building of $PGL_3$ over a nonarchimedean local field $F$. Analogous to a graph zeta function, $Z(X_Γ, u)$ is a rational function and it satisfies the Riemann hypothesis if and only if $X_Γ$ is a Ram

  97. Luis Dieulefait, Lucio Guerberoff, Ariel Pacetti

    We present an algorithm to determine if the $L$-series associated to an automorphic representation and the one associated to an elliptic curve over an imaginary quadratic field agree. By the work of Harris-Soudry-Taylor, Taylor and Berger-Harcos (cf. \cite{harris-taylor}, \cite{taylorII} and \cite{berger-harcos}) we can associate to an automorphic representa

  98. SELEX Collaboration, E. Vazquez-Jauregui, J. Engelfried

    We report the first observation of two Cabibbo-suppressed decay modes, Xi_c+ -> Sigma+ pi- pi+ and Xi_c+ -> Sigma- pi+ pi+. We observe 59+/-14 over a background of 87, and 22+/-8 over a background of 13 events, respectively, for the signals. The data were accumulated using the SELEX spectrometer during the 1996-1997 fixed target run at Fermilab, chiefly from

  99. B. Joachimi, P. Schneider

    To render cosmic shear an astronomical tool of high precision, it is essential to eliminate systematic effects upon its signal, one of the most significant ones being correlations between the gravitational shear and the intrinsic ellipticity of source galaxies. Because of the crudeness of current models of intrinsic alignment, we have developed a model-indep

  100. Valeria Akhmedova, Terry Pilling, Andrea de Gill, Douglas Singleton

    Recently, it has been shown that the radiation arising from quantum fields placed in a gravitational background (e.g. Hawking radiation) can be derived using a quasi-classical calculation. Here we show that this method has a previously overlooked temporal contribution to the quasi--classical amplitude. The source of this temporal contribution lies in differe