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December 2004 arXiv papers — page 7

Showing 601–700 of 3,961 papers

  1. Viviane Baladi

    We consider a smooth Anosov diffeomorphism with a smooth dynamical foliation. We show upper bounds on the essential spectral radius of its transfer operator acting on anisotropic Sobolev spaces. (Such bounds are related to the essential decorrelation rate for the SRB measure.) We compare our results to the estimates of Kitaev on the domain of holomorphy of d

  2. Marc Culler, Peter B Shalen

    We consider irreducible 3-manifolds M that arise as knot complements in closed 3-manifolds and that contain at most two connected strict essential surfaces. The results in the paper relate the boundary slopes of the two surfaces to their genera and numbers of boundary components. Explicit quantitative relationships, with interesting asymptotic properties, ar

  3. Ian M. Musson

    Let $\FRAK{g}$ be a classical simple Lie superalgebra. To every nilpotent orbit $\cal O$ in $\FRAK{g}_0$ we associate a Clifford algebra over the field of rational functions on $\cal O$. We find the rank, $k(\cal O)$ of the bilinear form defining this Clifford algebra, and deduce a lower bound on the multiplicity of a $U(\FRAK{g})$-module with $\cal O$ or an

  4. Sergey A. Melikhov

    P. M. Akhmetiev used a controlled version of the stable Hopf invariant to show that any (continuous) map N -> M between stably parallelizable compact n-manifolds, n\ne 1,2,3,7, is realizable in R^{2n}, i.e. the composition of f with an embedding M\subset R^{2n} is C^0-approximable by embeddings. It has been long believed that any degree 2 map S^3 -> S^3, obt

  5. Koenraad Schalm, Gary Shiu, Jan Pieter van der Schaar

    We provide a prescription for parametrizing the vacuum choice ambiguity in cosmological settings. We introduce an arbitrary boundary action representing the initial conditions. A Lagrangian description is moreover the natural setting to study decoupling of high-energy physics. RG flow affects the boundary interactions. As a consequence the boundary condition

  6. G. L. Cardoso, B. de Wit, J. Käppeli, T. Mohaupt

    It is shown that the asymptotic growth of the microscopic degeneracy of BPS dyons in four-dimensional N=4 string theory captures the known corrections to the macroscopic entropy of four-dimensional extremal black holes. These corrections are subleading in the limit of large charges and originate both from the presence of interactions in the effective action

  7. K. C. Hannabuss

    It is known that non-commutative fluids used to model the Fractional Quantum Hall effect give Calogero--Moser systems. The group-theoretic description of these as reductions of free motion on type A Lie algebras leads directly to Laughlin wave functions. The Calogero--Moser models also parametrise the right ideals of the Weyl algebra, which can be regarded a

  8. P. Di Vecchia, A. Tanzini

    We show that the complete planar one-loop mixing matrix of the N=2 Super Yang--Mills theory can be obtained from a reduction of that of the N=4 theory. For composite operators of scalar fields, this yields an anisotropic XXZ spin chain, whose spectrum of excitations displays a mass gap.

  9. Sergio Benvenuti, Amihay Hanany, Pavlos Kazakopoulos

    We construct all connected toric phases of the recently discovered $Y^{p,q}$ quivers and show their IR equivalence using Seiberg duality. We also compute the R and global U(1) charges for a generic toric phase of $Y^{p,q}$.

  10. Stephen Godfrey

    The observation of the D_{sJ}^*(2317), D_{sJ}(2460), and SELEX D^*_{sJ}(2632) states with properties differing considerably from what was expected has led to a renewed interest in hadron spectroscopy. In addition to these states, non-strange partners of the D_{sJ} states have also been observed. Understanding the D_0^* and D_1' states can provide importa

  11. Dietrich Bodeker, Lars Fromme, Stephan J. Huber, Michael Seniuch

    We study the generation of the baryon asymmetry in a variant of the standard model, where the Higgs field is stabilized by a dimension-six interaction. Analyzing the one-loop potential, we find a strong first order electroweak phase transition for Higgs masses up to at least 170 GeV. Dimension-six operators induce also new sources of CP violation. We compute

  12. C. S. Kim, Ya-Dong Yang

    The pure penguin process $B\to ϕK^*$ is one of the most important probes of physics beyond the Standard Model. Recently BaBar and Belle have measured the unexpectedly large transverse polarization in the decays $B\to ϕK^*$, which may single out new physics effects beyond the Standard model. We study the possibility that the phenomenon could serve as an impor

  13. G. P. Vacca

    The relation between the two approaches is discussed both in the linear and nonlinear regimes. It is connected to the gauge invariance and Moebius symmetry in LL perturbative QCD. First corrections beyond the large N approximation are discussed for the nonlinear case.

  14. F. Buisseret, C. Semay

    The contribution of the quark self energy to the meson masses is studied in the framework of the relativistic flux tube model. The equivalence between this phenomenological model and the more QCD based rotating string Hamiltonian is used as a guide to perform the calculations. It is shown that the addition of the quark self energy to the relativistic flux tu

  15. Xiao-Jun Bi, Tai-Fu Feng, Xue-Qian Li, Jukka Maalampi

    We analyze the charm quark electric dipole moment (EDM) in the minimal supersymmetric extension of the standard model (MSSM), including important two-loop gluino contributions. Considering the experimental constraint on the neutron EDM, the theoretical prediction for the charm quark EDM can reach about $10^{-20}e\cdot cm$. If taking into account the mixing b

  16. M. Baldicchi, G. M. Prosperi

    In line with some previous works, we study in this paper the meson spectrum in the framework of a second order quark-antiquark Bethe-Salpeter formalism which includes confinement. An analytic one loop running coupling constant alpha_s(Q), as proposed by Shirkov and Sovlovtsov, is used in the calculations. As for the quark masses, the case of a purely phenome

  17. K. Fialkowski, R. Wit

    The linear dependence of the particle spectra on rapidity is seen in the central region for asymmetric heavy ion collision in the data and in the Monte Carlo results, similarly as in the fragmentation region for hadronic and ion collisions. The origin of such a behaviour is discussed. It is shown that the color string models produce naturally such a shape if

  18. Chungku Kim

    We obtain the renormalization group improvement of the effective potential for the Coleman-Weinberg model by resumming the leading logarithms which have three different mass scales. Then, we investigate the effect of the multi-mass scale on the prediction of the magnitude of the Higgs boson mass by considering the two-loop effective potential.

  19. Christopher Lee, Vincenzo Cirigliano, Michael J. Ramsey-Musolf

    We compute the leading, chiral charge-changing relaxation term in the quantum transport equations that govern electroweak baryogenesis using the closed time path formulation of non-equilibrium quantum field theory. We show that the relaxation transport coefficients may be resonantly enhanced under appropriate conditions on electroweak model parameters and th

  20. Timothy Carruthers, Bruce H J McKellar

    The considerable influx of new data on B decays offers opportunities to determine some of the smaller contributions to the decay process, such as suppressed diagrams, and to test the relations between decay amplitudes implied by (broken) SU(3) symmetry. The graphical decomposition of decay amplitudes, corrected here for the contribution of electroweak pengui

  21. Frithjof Karsch

    We present recent lattice results on QCD thermodynamics at non-vanishing baryon number density obtained from a 6th order Taylor expansion in the chemical potential. Results for bulk thermodynamic observables, in particular for fluctuations in the baryon number density, are found to be well described by a hadron resonance gas model at low temperature and an i

  22. The BABAR Collaboration, B. Aubert et al

    We search for the decay B0 -> rho0 rho0 in a data sample of about 227 million Upsilon(4S)-> BBbar decays collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at SLAC. We find no significant signal and set an upper limit of 1.1*10^-6 at 90% CL on the branching fraction. As a result, the uncertainty due to penguin contributions on th

  23. A. Garmash

    We report results on the Dalitz analysis of three-body charmless B+=>K+Pi+Pi- and B+=>K+K+K- decays based on a 140 fb$^{-1}$ data sample collected with the Belle detector. Measurements of branching fractions for quasi-two-body decays to scalar-pseudoscalar states: B+ => f0(980)K+, B+ => K*_0(1430)^0 Pi+, and to vector-pseudoscalar states: B+ => K*(892)^0 Pi+

  24. Johannes M. Bauer

    Electromagnetic radiative penguin decays of the B meson were studied with the BaBar detector at SLAC's PEP-II asymmetric-energy B Factory. Branching fractions and isospin asymmetry of the decay B -> K* gamma, branching fractions of B -> K2*(1430) gamma, and a search for B0 -> phi gamma are presented. The decay rates may be enhanced by contributions from

  25. Dongning Guo, Shlomo Shamai, Sergio Verdu

    This paper deals with arbitrarily distributed finite-power input signals observed through an additive Gaussian noise channel. It shows a new formula that connects the input-output mutual information and the minimum mean-square error (MMSE) achievable by optimal estimation of the input given the output. That is, the derivative of the mutual information (nats)

  26. Koye Somefun, Tomas Klos, Han La Poutré

    In this paper, we consider a form of multi-issue negotiation where a shop negotiates both the contents and the price of bundles of goods with his customers. We present some key insights about, as well as a procedure for, locating mutually beneficial alternatives to the bundle currently under negotiation. The essence of our approach lies in combining aggregat

  27. Stefania Costantini

    This paper introduces a fundamental result, which is relevant for Answer Set programming, and planning. For the first time since the definition of the stable model semantics, the class of logic programs for which a stable model exists is given a syntactic characterization. This condition may have a practical importance both for defining new algorithms for ch

  28. Koye Somefun, Tomas Klos, Han La Poutré

    Combining two or more items and selling them as one good, a practice called bundling, can be a very effective strategy for reducing the costs of producing, marketing, and selling goods. In this paper, we consider a form of multi-issue negotiation where a shop negotiates both the contents and the price of bundles of goods with his customers. We present some k

  29. U. Gavish, Y. Castin

    We propose to observe Anderson localization of ultracold atoms in the presence of a random potential made of atoms of another species and trapped at the nodes of an optical lattice, with a filling factor less than unity. Such systems enable a nearly perfect experimental control of the disorder, while the possibility of modelling the scattering potentials by

  30. S. Das Sarma, E. H. Hwang

    Using the Drude-Boltzmann semiclassical transport theory, we calculate the weak-field Hall resistance of a two-dimensional system at low densities and temperatures, assuming carrier scattering by screened random charged impurity centers. The temperature dependent 2D Hall coefficient shows striking non-monotonicity in strongly screened systems, and in particu

  31. O. Derzhko, J. Richter, T. Krokhmalskii, O. Zaburannyi

    Using rigorous analytical analysis and exact numerical data for the spin-1/2 transverse Ising chain we discuss the effects of regular alternation of the Hamiltonian parameters on the quantum phase transition inherent in the model.

  32. J. Olson, M. Priester, J. Luo, S. Chopra

    In two-dimensional rotating drum experiments, we find two separate influences of the packing fraction of a granular heap on its stability. For a fixed grain shape, the stability increases with packing fraction. However, in determining the relative stability of different grain shapes, those with the lowest average packing fractions tend to form the most stabl

  33. R. Asgari, B. Davoudi, M. Polini, M. P. Tosi

    Motivated by a large number of recent magnetotransport studies we have revisited the problem of the microscopic calculation of the quasiparticle effective mass in a paramagnetic two-dimensional (2D) electron liquid (EL). Our systematic study is based on a generalized $GW$ approximation which makes use of the many-body local fields and takes advantage of the

  34. C. W. J. Beenakker, H. van Houten

    I. Introduction (Preface, Nanostructures in Si Inversion Layers, Nanostructures in GaAs-AlGaAs Heterostructures, Basic Properties). II. Diffusive and Quasi-Ballistic Transport (Classical Size Effects, Weak Localization, Conductance Fluctuations, Aharonov-Bohm Effect, Electron-Electron Interactions, Quantum Size Effects, Periodic Potential). III. Ballistic Tr

  35. M. D. Johannes, I. I. Mazin, D. J. Singh

    The puzzle of 3D magnetic interactions in the structurally 2D layered oxide Na$_{x}$CoO$_2$ is addressed using first principles calculations and analysis of the exchange mechanisms. The calculations agree with recent neutron results, favoring AFM stacking of FM planes. Superexchange via direct O-O hopping and through intermediate Na $sp^2$ hybrids couples ea

  36. M. Toreblad, Y. Yu, S. M. Reimann, M. Koskinen

    Vortices can form when finite quantal systems are set to rotate. In the limit of small particle numbers the vortex formation in a harmonically trapped fermion system, with repulsively interacting particles, shows similarities to the corresponding boson system, with vortices entering the rotating cloud for increasing rotation. We show that for a larger number

  37. Carlos P. Herrero

    Several kinds of walks on complex networks are currently used to analyze search and navigation in different systems. Many analytical and computational results are known for random walks on such networks. Self-avoiding walks (SAWs) are expected to be more suitable than unrestricted random walks to explore various kinds of real-life networks. Here we study lon

  38. Rachana Gupta, Mukul Gupta

    Thin films of iron and permalloy Ni80Fe20 were prepared using an Ar+N2 mixture with magnetron sputtering technique at ambient temperature. The nitrogen partial pressure, during sputtering process was varied in the range of 0 to 100%, keeping the total gas flow at constant. At lower nitrogen pressures RN2<33% both Fe and NiFe, first form a nanocrystalline str

  39. X. N. Zhang, P. Lemmens, V. Gnezdilov, K. Y. Choi

    Raman scattering experiments have been performed on Na_xCoO_2 as function of temperature at the composition x=0.5 where a structural instability and a metal-insulator transition have been observed. Three additional phonon modes are observed compared to samples with larger x. An in-situ annealing study (T_max=550 K) with the initial presence of water vapor at

  40. Raja Paul, Heiko Rieger

    The non-equilibrium dynamics of condensation phenomena in nano-pores is studied via Monte Carlo simulation of a lattice gas model. Hysteretic behavior of the particle density as a function of the density of a reservoir is obtained for various pore geometries in two and three dimensions. The shape of the hysteresis loops depend on the characteristics of the p

  41. Alexander V. Tsukanov

    We study theoretically the quantum dynamics of two interacting electrons in the symmetric double-dot structure under the influence of the bichromatic resonant pulse. The state vector evolution is studied for two different pulse designs. It is shown that the laser pulse can generate the effective exchange coupling between the electron spins localized in diffe

  42. Demian Battaglia, Alfredo Braunstein, Joël Chavas, Riccardo Zecchina

    In this letter, we show how the Survey Propagation algorithm can be generalized to include external forcing messages, and used to address selectively an exponential number of glassy ground states. These capabilities can be used to explore efficiently the space of solutions of random NP-complete constraint satisfaction problems, providing a direct experimenta

  43. O. Cepas, H. R. Krishnamurthy, T. V. Ramakrishnan

    We argue that many properties of the half-doped manganites may be understood in terms of a new two-(eg electron)-fluid description, which is energetically favorable at intermediate Jahn-Teller (JT) coupling. This emerges from a competition between canting of the core spins of Mn promoting mobile carriers and polaronic trapping of carriers by JT defects, in t

  44. F. Ritort

    In this paper we introduce the generalized oscillator model (GOM) as a family of exactly solvable models useful to investigate theoretical aspects related to the statistical description of the aging state. GOMs are defined by a potential function V(x) and characterized by a zero-temperature relaxation determined by entropy barriers and partial equilibration.

  45. E. V. R. Chan

    The source code for resonant x-ray magnetic scattering (RXMS) data analysis is available. It includes measures of the radial variation of intensity and ability to extract azimuthal angular variation of intensity within the transmission geometry. If you need assistance to modify my code please email.

  46. John W. Barrett, Leonid Prigozhin

    Similar evolutionary variational inequalities appear as convenient formulations for continuous models for sandpile growth, magnetization of type-II superconductors, and evolution of some other dissipative systems characterized by the multiplicity of metastable states, long-range interactions, avalanches, and hysteresis. The origin of this similarity is that

  47. Takahiro Maehira, Takashi Hotta, Kazuo Ueda, Akira Hasegawa

    By using a relativistic linear augmented-plane-wave method with the one-electron potential in the local-density approximation, we investigate energy band structures and the Fermi surfaces of transuranium compounds NpTGa$_5$, PuTGa$_5$, and AmCoGa$_5$ with transition metal atoms T. It is found in common that the energy bands in the vicinity of the Fermi level

  48. M T Batchelor, X-W Guan, C Dunning, J Links

    We consider the asymptotic solutions to the Bethe ansatz equations of the integrable model of interacting bosons in the weakly interacting limit. In this limit we establish that the ground state maps to the highest energy state of a strongly-coupled repulsive bosonic pairing model.

  49. G. Cristadoro, D. L. Shepelyansky

    An ensemble of particles in thermal equilibrium at temperature $T$, modeled by Nosè-Hoover dynamics, moves on a triangular lattice of oriented semi-disk elastic scatterers. Despite the scatterer asymmetry a directed transport is clearly ruled out by the second law of thermodynamics. Introduction of a polarized zero mean monochromatic field creates a directed

  50. K. M. Stevens, W. A. Atkinson

    This paper has been withdrawn due to a sign error in the equation for F_11 which invalidates many results.

  51. J. Chang, Y. H. Su, H. G. Luo, H. T. Lu

    A strong nonmagnetic impurity can induce a resonance state in the d-wave superconducting state. As far as magnetic properties are concerned, this resonance state behaves effectively like a free moment. It leads to a Curie-Weiss-like magnetic susceptibility in an intermediate temperature regime below $T_{c}$. From the impurity susceptibility, the effective mo

  52. Neil P. Oxtoby, P. Warszawski, H. M. Wiseman, He-Bi Sun

    We present a new model for the continuous measurement of a coupled quantum dot charge qubit. We model the effects of a realistic measurement, namely adding noise to, and filtering, the current through the detector. This is achieved by embedding the detector in an equivalent circuit for measurement. Our aim is to describe the evolution of the qubit state cond

  53. Kirill N. Alekseev, Ethan H. Cannon, Feodor V. Kusmartsev, David K. Campbell

    We consider the spontaneous creation of a dc voltage across a strongly coupled semiconductor superlattice subjected to THz radiation. We show that the dc voltage may be approximately proportional either to an integer or to a half- integer multiple of the frequency of the applied ac field, depending on the ratio of the characteristic scattering rates of condu

  54. W. de Boer

    The EGRET excess in the diffuse galactic gamma ray data above 1 GeV 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. b) The intensity of the excess shows the $1/r^2$ profile expected for a flat rotation curve outside the galactic disc with addi

  55. s Eye Collaboration, G. R. Farrar

    We present the results of a search for cosmic ray point sources at energies above 40 EeV in the combined data sets recorded by the AGASA and HiRes stereo experiments. The analysis is based on a maximum likelihood ratio test using the probability density function for each event rather than requiring an a priori choice of a fixed angular bin size. No statistic

  56. R. Zamanov, A. Gomboc, M. F. Bode, J. M. Porter

    We report our search for variability in the H-alpha emission line of the recurrent novae T CrB with time resolution 10-15 minutes. This is comparable with the time scale of the photometric flickering observed in this object. This is the first time that observations of the short time scale variation in emission lines have been made in this object. On two nigh

  57. M. Kleinheinrich, P. Schneider, H. -W. Rix, T. Erben

    We present a measurement of mass estimates for dark matter halos around galaxies from the COMBO-17 survey using weak gravitational lensing. COMBO-17 is particularly useful for this kind of investigation because it covers observations in 17 optical filters from which accurate photometric redshifts and spectral classification for objects with $R<24$ are derive

  58. Slawomir Stachniewicz, Marek Kutschera

    We study the evolution of a spherically symmetric density perturbation in the Modified Newtonian Dynamics (MOND) model applied to the net acceleration over Hubble flow. The background cosmological model is a $Λ$-dominated, low-$Ω_b$ Friedmann model with no Cold Dark Matter. We include thermal processes and non-equilibrium chemical evolution of the collapsing

  59. Jan Palous

    A review of gravitational and hydrodynamical processes during formation of clusters and evolution of galaxies is given. Early, at the advent of N-body computer simulations, the importance of tidal fields in galaxy encounters has been recognized. Orbits are crowded due to tides along spiral arms, where the star formation is enhanced. Low relative velocity enc

  60. P. Cerda-Duran, G. Faye, H. Dimmelmeier, J. A. Font

    Core collapse supernovae are a promising source of detectable gravitational waves. Most of the existing (multidimensional) numerical simulations of core collapse in general relativity have been done using approximations of the Einstein field equations. As recently shown by Dimmelmeier et al (2002a,b), one of the most interesting such approximation is the so-

  61. A. Haungs, T. Antoni

    KASCADE is a multi-detector setup to get redundant information on single air shower basis. The information is used to perform multiparameter analyses to solve the threefold problem of the reconstruction of (i)the unknown primary energy, (ii) the primary mass, and (iii) to quantify the characteristics of the hadronic interactions in the air-shower development

  62. M. R. Calabretta

    The natural spherical projection associated with the Hierarchical Equal Area and isoLatitude Pixelisation, HEALPix, is described and shown to be one of an infinite class not previously documented in the cartographic literature. Projection equations are derived for the class in general and it is shown that the HEALPix projection suggests a simple method (a) o

  63. Matthew P. Young

    We show that a large number of elliptic curve L-functions do not vanish at the central point, conditionally on the generalized Riemann hypothesis and on a hypothesis on the regular distribution of the root number.

  64. Kieran A. Cleary, Angela C. Taylor, Elizabeth Waldram, Richard A. Battye

    We describe the source subtraction strategy and observations for the extended Very Small Array, a CMB interferometer operating at 33 GHz. A total of 453 sources were monitored at 33 GHz using a dedicated source subtraction baseline. 131 sources brighter than 20 mJy were directly subtracted from the VSA visibility data. Some characteristics of the subtracted

  65. Thomas W. Grimm, Jan Louis

    The N=1 effective action for generic type IIA Calabi-Yau orientifolds in the presence of background fluxes is computed from a Kaluza-Klein reduction. The Kahler potential, the gauge kinetic functions and the flux-induced superpotential are determined in terms of geometrical data of the Calabi-Yau orientifold and the background fluxes. The moduli space is fou

  66. A. V. Efremov, K. Goeke, S. Menzel, A. Metz

    The Sivers parton distribution has been predicted to obey a particular ``universality relation&#39;&#39;, namely to have opposite sign in semi-inclusive deeply inelastic scattering (SIDIS) and the Drell-Yan process. We discuss how, on the basis of present HERMES data, this remarkable prediction of the QCD factorization approach to the description of single s

  67. Fei Lin, Jurij Smakov, Erik S. Sorensen, Catherine Kallin

    We generalize the imaginary chemical potential quantum Monte Carlo (QMC) method proposed by Dagotto et al. [Phys. Rev. B 41, R811 (1990)] to systems without particle-hole symmetry. The generalized method is tested by comparing the results of the QMC simulations and exact diagonalization on small Hubbard molecules, such as tetrahedron and truncated tetrahedro

  68. S. V. Kozyrev

    A family of orthonormal bases of ultrametric wavelets in the space of quadratically integrable with respect to arbitrary measure functions on general (up to some topological restrictions) ultrametric space is introduced. Pseudodifferential operators (PDO) on the ultrametric space are investigated. We prove that these operators are diagonal in the introduced

  69. G. F. Bertsch, B. Sabbey, M. Uusnakki

    In developing theories of nuclear binding energy such as density-functional theory, the effort required to make a fit can be daunting due to the large number of parameters that may be in the theory and the large number of nuclei in the mass table. For theories based on the Skyrme interaction, the effort can be reduced considerably by using the singular value

  70. Abdesslam Arhrib, Rachid Benbrik

    The complete one-loop radiative corrections to third generation scalar fermions into gauge bosons Z and W^\pm is considered. We focus on \wt{f}_2 \to Z \wt{f}_1 and \wt{f}_i \to W^\pm \wt{f&#39;}_j (f,f&#39;=t,b). We include both SUSY-QCD, QED and full electroweak corrections. It is found that the electroweak corrections can be of the same order as the SUSY-

  71. P. A. Baikov, K. G. Chetyrkin, J. H. Kühn

    The first complete calculation of the quadratic quark mass correction to the correlator of the two currents relevant for the strangeness-changing semihadronic tau-decay rate is presented including its real part at the four-loop level. This allows to perform the extraction of the strange quark mass m_s from the decay width of the tau-lepton with full O(alpha_

  72. J. Barea, R. Bijker, A. Frank

    The spectroscopic strengths of two-nucleon transfer reactions constitute a stringent test for two-nucleon correlations in the nuclear wave functions. A comparison between the recently measured 198Hg(d,alpha)196Au reaction and the predictions from the nuclear quartet supersymmetry lends further support to the validity of supersymmetry in nuclear physics.

  73. Cedric Deffayet

    We investigate the cosmological perturbations of the brane-induced (Dvali-Gabadadze-Porrati) model which exhibits a van Dam-Veltman-Zakharov (vDVZ) discontinuity when linearized over a Minkowski background. We show that the linear brane scalar cosmological perturbations over an arbitrary Friedmann-Lemaitre-Robertson-Walker (FLRW) space-time have a well defin

  74. Guy D. Moore, Derek Teaney

    We investigate the thermalization of charm quarks in high energy heavy ion collisions. To this end, we calculate the diffusion coefficient in the perturbative Quark Gluon Plasma and relate it to collisional energy loss and momentum broadening. We then use these transport properties to formulate a Langevin model for the evolution of the heavy quark spectrum i

  75. K. H. Ahn, A. J. Fedro, Michel van Veenendaal

    Using a model Hamiltonian, we discuss how we could interpret data obtained from transition metal $K$-edge resonant inelastic x-ray scattering (RIXS) experiments. By analyzing the creation of valence excitations from the screening of the core hole and calculating corresponding RIXS spectra for metals and insulators, we find that the probability for excitation

  76. Massimo Giovannini

    This review presents, in a self-consistent manner, those analytical tools that are relevant for the analysis of the physics of CMB anisotropies generated in different theoretical models of the early Universe. After introducing the physical foundations of the Sachs-Wolfe effect, the origin and evolution of the scalar, tensor and vector modes of the geometry i

  77. C. J. Umrigar, Claudia Filippi

    We present a simple, robust and efficient method for varying the parameters in a many-body wave function to optimize the expectation value of the energy. The effectiveness of the method is demonstrated by optimizing the parameters in flexible Jastrow factors, that include 3-body electron-electron-nucleus correlation terms, for the NO$_2$ and decapentaene (C$

  78. Pavel Fileviez Perez

    We investigate in detail the predictions coming from the d=4 operators for proton decay. We find the most general constraints for the R-parity violating couplings coming from proton decay, taking into account all fermion mixing and in different supersymmetric scenarios.

  79. V. Sood, S. Redner

    We study the voter dynamics model on heterogeneous graphs. We exploit the non-conservation of the magnetization to characterize how consensus is reached on networks with different connectivity patterns. For a network of N sites with an arbitrary degree distribution, we show that the mean time to reach consensus T_N scales as N mu_1^2/mu_2, where mu_k is the

  80. Alexander D. Hernandez, Daniel Dominguez

    We present simulations of the intermediate state of type-I superconducting films solving the time dependent Ginzburg-Landau equations, which include the demagnetizing fields via the Biot-Savart law. For small square samples we find that, when slowly increasing the applied magnetic field $H_a$, there is a saw-tooth behavior of the magnetization and very geome

  81. Jeroen Homan, Tomaso Belloni

    We discuss the evolution of black hole transients on the basis of a few systems that were intensively observed with the Rossi X-ray Timing Explorer. We focus on the global evolution and the observed state transitions. Rather than giving a numerical recipe for classifying observations, we try to identify times during outbursts at which clear changes occur in

  82. G. I. Boishin, J. M. Sullivan, L. J. Whitman

    Cross sectional scanning tunneling microscopy (XSTM) and density functional theory have been used to characterize the structure of GaSb digitally doped with Mn. The Mn dopants are found in both isolated substitutional form as well as in large clusters of zinc-blende MnSb commensurate with the surrounding GaSb matrix. Theoretical calculations predict that the

  83. A. Szostek, A. A. Zdziarski

    We model the ~1-200 keV spectra of Cygnus X-3 observed by BeppoSAX. The continuum, modeled by Comptonization in a hybrid plasma, is modified by the strongly ionized plasma of the stellar wind of the Wolf-Rayet companion star. Discrete absorption and emission spectral features are modeled with XSTAR. The model has been applied to phase-resolved spectra in the

  84. Johannes Walcher

    We evaluate the ideas of Pi-stability at the Landau-Ginzburg point in moduli space of compact Calabi-Yau manifolds, using matrix factorizations to B-model the topological D-brane category. The standard requirement of unitarity at the IR fixed point is argued to lead to a notion of &#34;R-stability&#34; for matrix factorizations of quasi-homogeneous LG potent

  85. A. A. Schekochihin, N. E. L. Haugen, A. Brandenburg, S. C. Cowley

    We study numerically the dependence of the critical magnetic Reynolds number Rmc for the turbulent small-scale dynamo on the hydrodynamic Reynolds number Re. The turbulence is statistically homogeneous, isotropic, and mirror--symmetric. We are interested in the regime of low magnetic Prandtl number Pm=Rm/Re<1, which is relevant for stellar convective zones,

  86. Sascha Ledowski, Peter Kopietz, Alvaro Ferraz

    Using functional renormalization group methods, we present a self-consistent calculation of the true Fermi momenta k_F^a (antibonding band) and k_F^b (bonding band) of two spinless interacting metallic chains coupled by small interchain hopping. In the regime where the system is a Luttinger liquid, we find that Delta = k_F^b - k_F^a is self-consistently dete

  87. Elias Gravanis, Steven Willison

    Colliding and intersecting hypersurfaces filled with matter (membranes) are studied in the Lovelock higher order curvature theory of gravity. Lovelock terms couple hypersurfaces of different dimensionalities, extending the range of possible intersection configurations. We restrict the study to constant curvature membranes in constant curvature AdS and dS bac

  88. Yu. S. Kalashnikova, A. E. Kudryavtsev, A. V. Nefediev, C. Hanhart

    We investigate the radiative decays of the $ϕ$ meson to the scalar mesons $a_0(980)$ and $f_0(980)$. We demonstrate that, contrary to earlier claims, these decays should be of the same order of magnitude for a molecular state and for a compact state and, therefore, the available experimental information is consistent with both, a molecular as well as a compa

  89. K. Behnia, R. Bel, Y. Kasahara, Y. Nakajima

    We present a study of thermal conductivity in the normal state of the heavy-fermion superconductor URu$_{2}$Si$_{2}$. Ordering at 18K leads to a steep increase in thermal conductivity and (in contrast with all other cases of magnetic ordering in heavy-fermion compounds) to an enhancement of the Lorenz number. By linking this observation to several other prev

  90. A. Tawfik

    We compare the lattice results on QCD phase diagram for two and three flavors with the hadron resonance gas model (HRGM) calculations. Lines of constant energy density $ε$ have been determined at different baryo-chemical potentials $μ_B$. For the strangeness chemical potentials $μ_S$, we use two models. In one model, we explicitly set $μ_S=0$ for all tempera

  91. Y. Brihaye, N. Debergh, A. Nininahazwe

    We extend the exactly solvable Hamiltonian describing $f$ quantum oscillators considered recently by J. Dorignac et al. by means of a new interaction which we choose as quasi exactly solvable. The properties of the spectrum of this new Hamiltonian are studied as function of the new coupling constant. This Hamiltonian as well as the original one are also rela

  92. A. E. Bondar, V. L. Chernyak

    It is shown that difficulties in reconciling the values of the cross section e+e- -> J/psi+eta_c measured at BELLE and calculated within non-relativistic QCD (NRQCD) are caused not by some misinterpretation of the data or other exotic explanations, but by poor applicability of NRQCD to such processes. We use general theory of hard exclusive processes in QCD

  93. Rajiv V. Gavai, Sourendu Gupta, Swagato Mukherjee

    We report the continuum limits of the speed of sound, c_s, and the specific heat at constant volume, c_v, in quenched QCD at temperatures of 2Tc and 3Tc. At these temperatures, c_s is within 2-sigma of the ideal gas value, whereas c_v differs significantly from the ideal gas. However, both are compatible with results expected in a theory with conformal symme

  94. Ezio Vasselli

    We study C*-algebra endomorphims which are special in a weaker sense w.r.t. the notion introduced by Doplicher and Roberts. We assign to such endomorphisms a geometrical invariant, representing a cohomological obstruction for them to be special in the usual sense. Moreover, we construct the crossed product of a C*-algebra by the action of the dual of a (nona

  95. Semjon Stepanow

    Using the exact computation of a large number of moments of the distribution function of the end-to-end distance $G(r,N)$ of the worm-like chain, we have established the analytical form of the coefficients in Taylor expansions of the moments for short chain lengths $N$. The knowledge of these coefficients enabled us to resummate the moment expansion of $G(r,

  96. D. F. Carneiro, E. A. Freiras, B. Gonçalves, A. G. de Lima

    Local conformal transformations are known as a useful tool in various applications of the gravitational theory, especially in cosmology. We describe some new aspects of these transformations, in particular using them for derivation of Einstein equations for the cosmological and Schwarzschild metrics. Furthermore, the conformal transformation is applied for t

  97. Einat Klein, Rachel Mislovaty, Ido Kanter, Wolfgang Kinzel

    We present a key-exchange protocol that comprises two parties with chaotic dynamics that are mutually coupled and undergo a synchronization process, at the end of which they can use their identical dynamical state as an encryption key. The transferred coupling-signals are based non-linearly on time-delayed states of the parties, and therefore they conceal th

  98. R. V. Gavai, Sourendu Gupta

    We investigate the critical end point of QCD with two flavours of light dynamical quarks at finite lattice cutoff a=1/4T using a Taylor expansion of the baryon number susceptibility. We find a strong volume dependence of the position of the critical end point. In the large volume limit we obtain T^E/T_c \~ 0.95 and mu_B^E/T^E ~ 1.1, where T_c is the cross ov

  99. Aparna Chakrabarti, C. Biswas, S. Banik, R. S. Dhaka

    The modifications in the electronic structure of Ni_{2+x}Mn_{1-x}Ga by Ni doping have been studied using full potential linearized augmented plane wave method and ultra-violet photoemission spectroscopy. Ni 3d related electron states appear due to formation of Ni clusters. We show the possibility of changing the minority-spin DOS with Ni doping, while the ma

  100. Mats Andersson

    We prove a generalization of the classical Poincaré-Lelong formula. Given a holomorphic section $f$, with zero set $Z$, of a Hermitian vector bundle $E\to X$, let $S$ be the line bundle over $X\setminus Z$ spanned by $f$ and let $Q=E/S$. Then the Chern form $c(D_Q)$ is locally integrable and closed in $X$ and there is a current $W$ such that $dd^cW=c(D_E)-c(