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September 2006 arXiv papers — page 34

Showing 3,3013,400 of 4,533 papers

  1. Christopher W. Stubbs, Sara K. Slater, Yorke J. Brown, Daniel Sherman

    We describe the scientific motivation for achieving photometric precision and accuracy below the 1% level, and we present a calibration philosophy based on using calibrated detectors rather than celestial sources as the fundamental metrology reference. A description of the apparatus and methodology is presented, as well as preliminary measurements of relativ

  2. C. Melo, N. C. Santos, F. Pont, T. Guillot

    Results of photometric surveys have brought to light the existence of a population of giant planets orbiting their host stars even closer than the hot Jupiters (HJ), with orbital periods below 3 days. The reason why radial velocity surveys were not able to detect these very-hot Jupiters (VHJ) is under discussion. A possible explanation is that these close-in

  3. C. A. O. Torres, G. R. Quast, L. da Silva, R. de la Reza

    We report results from a high-resolution optical spectroscopic survey aimed to search for nearby young associations and young stars among optical counterparts of ROSAT All-Sky Survey X-ray sources in the Southern Hemisphere. We selected 1953 late-type (B-V >= 0.6), potentially young, optical counterparts out of a total of 9574 1RXS sources for follow-up obse

  4. Guenter Sigl

    We give a brief overview of the current experimental and theoretical status of cosmic rays above ~10**17 eV. We focus on the role of large scale magnetic fields and on multi-messenger aspects linking charged cosmic ray with secondary gamma-ray and neutrino fluxes.

  5. Mercedes Lopez-Morales, Nidia I. Morrell, R. Paul Butler, Sara Seager

    We have monitored the Neptune-mass exoplanet-hosting M-dwarf Gl 581 with the 1m Swope Telescope at Las Campanas Observatory over two predicted transit epochs. A neutral density filter centered at 550nm was used during the first epoch, yielding 6.33 hours of continuous light curve coverage with an average photometric precision of 1.6 mmags and a cadence of 2.

  6. L. Mathey, S. -W. Tsai, A. H. Castro Neto

    We study the phase diagram of two-dimensional Bose-Fermi mixtures of ultracold atoms on a triangular optical lattice, in the limit when the velocity of bosonic condensate fluctuations is much larger than the Fermi velocity. We contrast this work with our previous results for a square lattice system in Phys. Rev. Lett. {\bf 97}, 030601 (2006). Using functiona

  7. Bernd A. Berg, Chizuru Muguruma, Yuko Okamoto

    We introduce two simple models with nearest neighbor interactions on 3D hexagonal lattices. Each model allows one to calculate the residual entropy of ice I (ordinary ice) by means of multicanonical simulations. This gives the correction to the residual entropy derived by Linus Pauling in 1935. Our estimate is found to be within less than 0.1% of an analytic

  8. Earle L. Lomon

    The extended Gari-Krumpelmann (GK) model of nucleon electromagnetic form factors, in which the $ρ$, $ρ'$, $ω$, $ω'$ and $ϕ$ vector meson pole contributions evolve at high momentum transfer to conform to the predictions of perturbative QCD (pQCD), was recently shown to provide a very good overall fit to all the nucleon electromagnetic form factor (emf

  9. Ari Mizel, Daniel A. Lidar, Morgan Mitchell

    We prove the equivalence between adiabatic quantum computation and quantum computation in the circuit model. An explicit adiabatic computation procedure is given that generates a ground state from which the answer can be extracted. The amount of time needed is evaluated by computing the gap. We show that the procedure is computationally efficient.

  10. Karen L. Masters, Christopher M. Springob, Martha P. Haynes, Riccardo Giovanelli

    The SFI++ consists of ~5000 spiral galaxies which have measurements suitable for the application of the I-band Tully-Fisher (TF) relation. This sample builds on the SCI and SFI samples published in the 1990s but includes significant amounts of new data as well as improved methods for parameter determination. We derive a new I-band TF relation from a subset o

  11. M. B. Gay Ducati, M. M. Machado, M. V. T. Machado

    We present an exploratory QCD analysis of the neutrino structure functions in charged current DIS using the color dipole formalism. The dipole cross sections are taken from recent phenomenological/theoretical studies in deep inelastic inclusive production. The theoretical predictions are compared to the available experimental results in the small-x region, w

  12. Ayman Kachmar

    We formulate a spectral problem related to the onset of superconductivity for a generalized Ginzburg-Landau model, where the order parameter and the magnetic potential are defined in the whole space. This model is devoted to the `proximity effect' for a superconducting sample surrounded by a normal material. In the regime when the Ginzburg-Landau paramet

  13. W. Eerenstein, M. Wiora, J. L. Prieto, J. F. Scott

    Magnetoelectric coupling permits a magnetic order parameter to be addressed electrically or vice versa, and could find use in data storage, field sensors and actuators. Coupling constants for single phase materials such as chromium dioxide, boracites and manganites are typically as low as 10^{-12} - 10^{-9} s/m, e.g. because the polarisations and magnetisati

  14. P. C. Gregory

    An automatic Bayesian Kepler periodogram has been developed for identifying and characterizing multiple planetary orbits in precision radial velocity data. The periodogram is powered by a parallel tempering MCMC algorithm which is capable of efficiently exploring a multi-planet model parameter space. The periodogram employs an alternative method for converti

  15. Qayum Khan

    Let F be a finite group with a Sylow 2-subgroup S that is normal and abelian. Using hyperelementary induction and cartesian squares, we prove that Cappell's unitary nilpotent groups UNil_*(Z[F];Z[F],Z[F]) have an induced isomorphism to the quotient of UNil_*(Z[S];Z[S],Z[S]) by the action of the group F/S. In particular, any finite group F of odd order ha

  16. David Delepine, Carlos Martinez, L. Arturo Urena-Lopez

    We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U(1) global symmetry associated to the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry.

  17. Alexander Kusenko

    We identify the range of parameters for which the sterile neutrinos can simultaneously explain the cosmological dark matter and the observed velocities of pulsars. To satisfy all cosmological bounds, the relic sterile neutrinos must be produced sufficiently cold. This is possible in a class of models with a gauge-singlet Higgs boson coupled to the neutrinos.

  18. Maria E. De Rossi, Patricia B. Tissera, Cecilia Scannapieco

    We analyse the evolutionary history of galaxies formed in a hierarchical scenario consistent with the concordance $Λ$-CDM model focusing on the study of the relation between their chemical and dynamical properties. Our simulations consistently describe the formation of the structure and its chemical enrichment within a cosmological context. Our results indic

  19. Matthew S. Tiscareno, Philip D. Nicholson, Joseph A. Burns, Matthew M. Hedman

    We describe a model that accounts for the complex morphology of spiral density waves raised in Saturn's rings by the co-orbital satellites, Janus and Epimetheus. Our model may be corroborated by future Cassini observations of these time-variable wave patterns.

  20. D. Grumiller, R. Jackiw

    Kaluza-Klein reduction of conformally flat spaces is considered for arbitrary dimensions. The corresponding equations are particularly elegant for the reduction from four to three dimensions. Assuming circular symmetry leads to explicit solutions which also arise from specific two-dimensional dilaton gravity actions.

  21. A. Cuoco, G. Mangano, G. Miele, S. Pastor

    We perform a study of the ultra high energy neutrino detection performances of a km^3 Neutrino Telescope sitting at the three proposed sites for ANTARES, NEMO and NESTOR in the Mediterranean sea. We focus on the effect of the underwater surface profile on the total amount of yearly expected tau and mu crossing the fiducial volume in the limit of full detecti

  22. C. M. Johns-Krull, G. J. Herczeg

    It has recently been suggested that the winds from Classical T Tauri stars in general, and the wind from TW Hya in particular, reaches temperatures of at least 300,000 K while maintaing a mass loss rate of $\sim 10^{-11}$ \Msol yr$^{-1}$ or larger. If confirmed, this would place strong new requirements on wind launching and heating models. We therefore re-ex

  23. Panagiotis Drouvelis, Giorgos Fagas, Peter Schmelcher

    Quantum transport through an open periodic array of up to five dots is investigated in the presence of a magnetic field. The device spectrum exhibits clear features of the band structure of the corresponding one-dimensional artificial crystal which evolves with varying field. A significant magnetically controlled current flow is induced with changes up to ma

  24. L. A. Fernandez, V. Martin-Mayor, P. Verrocchio

    The phase diagram of soft spheres with size dispersion has been studied by means of an optimized Monte Carlo algorithm which allows to equilibrate below the kinetic glass transition for all sizes distribution. The system ubiquitously undergoes a first order freezing transition. While for small size dispersion the frozen phase has a crystalline structure, lar

  25. A. Zabrodin

    This paper is a short review of the connection between certain types of growth processes and the integrable systems theory, written from the viewpoint of the latter. Starting from the dispersionless Lax equations for the 2D Toda hierarchy, we interpret them as evolution equations for conformal maps in the plane. This provides a unified approach to evolution

  26. Alexander Kuznetsov

    Let $Y$ be a singular algebraic variety and let $\TY$ be a resolution of singularities of $Y$. Assume that the exceptional locus of $\TY$ over $Y$ is an irreducible divisor $\TZ$ in $\TY$. For every Lefschetz decomposition of $\TZ$ we construct a triangulated subcategory $\TD \subset \D^b(\TY)$ which gives a desingularization of $\D^b(Y)$. If the Lefschetz d

  27. Barbara Betz, Dirk H. Rischke

    Hot and/or dense, normal-conducting systems of relativistic fermions exhibit a particular collective excitation, the so-called plasmino. We compute the one-loop self-energy, the dispersion relation and the spectral density for fermions interacting via attractive boson exchange. It is shown that plasminos also exist in superconductors.

  28. Arti Chamoli, C. M. Bhandari

    Evolution of entanglement with the proceeding of quantum algorithms affects the outcome of the algorithm. Particularly, the performance of Grover's search algorithm gets worsened if the initial state of the algorithm is an entangled one. The success probability of search can be seen as an operational measure of entanglement. This paper demonstrates an en

  29. Maximilian Stritzinger, Paolo Mazzali, Jesper Sollerman, Stefano Benetti

    We present (56)Ni mass estimates for seventeen well-observed type Ia supernovae determined by two independent methods. Estimates of the (56)Ni mass for each type Ia supernova are determined from (1) modeling of the late-time nebular spectrum and (2) through the combination of the peak bolometric luminosity with Arnett's rule. The attractiveness of this a

  30. Said Benachour, Simona Dabuleanu

    We prove the existence and the uniqueness of strong solutions for the viscous Hamilton-Jacobi Equation with Neumann boundary condition and initial data a continious function. Then, we study the large time behavior of the solutions.

  31. V. P. Berezovoj, Yu. L. Bolotin, G. I. Ivashkevych

    We use so-called geometrical approach in description of transition from regular motion to chaotic in Hamiltonian systems with potential energy surface that has several local minima. Distinctive feature of such systems is coexistence of different types of dynamics (regular or chaotic) in different wells at the same energy Mixed state reveals unique opportunit

  32. Joris A. D. L. Blommaert, Martin A. T. Groenewegen, Koryo Okumura, Shashikiran Ganesh

    To study the nature of Bulge AGB stars and in particular their circumstellar dust, we have analysed mid-infrared spectra obtained with the ISOCAM CVF spectrometer in three Bulge fields. The ISOCAM 5-16.5 micron CVF spectra were obtained as part of the ISOGAL infrared survey of the inner Galaxy. A classification of the shape of the 10 micron dust feature was

  33. Robabeh Rahimi

    In this work, we have been working on the concept of quantum entanglement. At first, we studied the theory of entanglement in its characterization and measurement, introducing a new scheme for detection of entanglement. The new approach links molecular-spin entities involving nuclear spins to quantum computing as more appropriate physical systems of interest

  34. Wei Wang, Yue-Long Shen, Ying Li, Cai-Dian Lu

    Within perturbative QCD approach based on $k_T$ factorization, we analyze the scalar mesons $f_0(980)$ and $f_0(1500)$ productions in B decays. By identifying $f_0(980)$ as the composition of $\bar ss$ and $\bar nn=(\bar uu+\bar dd)/\sqrt2$, we calculate the exclusive decays $B\to f_0(980) K$. We find that the non-factorization $f_0$-emission diagrams can gi

  35. Florentin Smarandache, V. Christianto, Fu Yuhua, R. Khrapko

    Throughout this book, we discuss some open problems in various branches of science, including mathematics, theoretical physics, astro-physics, geophysics etc. It is of our hope that some of the problems discussed in this book will find their place either in theoretical exploration or further experiments, while some parts of these problems may be found useful

  36. M. Novello

    The proposal of this work is to provide an answer to the following question: is it possible to treat the metric of space-time - that in General Relativity (GR) describes the gravitational interaction - as an effective geometry? In other words, to obtain the dynamics of the metric tensor as a consequence of the dynamics of other fields. In this work we will u

  37. S. Turgut

    Landauer's erasure principle is generalized to nondeterministic processes on systems having an arbitrary number of non-symmetrical logical states. The condition that the process is applied in the same way, irrespective of the initial logical state, imposes some restrictions on the individual heat exchanges associated with each possible transition. The co

  38. Olivier Siegenthaler

    Based on the work of Abercrombie, Barnea and Shalev gave an explicit formula for the Hausdorff dimension of a group acting on a rooted tree. We focus here on the binary tree T. Abert and Virag showed that there exist finitely generated (but not necessarily level-transitive) subgroups of AutT of arbitrary dimension in [0,1]. In this article we explicitly comp

  39. A. Hietanen, A. Kurkela

    We use high precision lattice simulations to calculate the plaquette expectation value in three-dimensional SU(N) gauge theory for N=2,3,4,5,8. Using these results, we study the N-dependence of the first non-perturbative coefficient in the weak-coupling expansion of hot QCD. We demonstrate that, in the limit of large N, the functional form of the plaquette e

  40. Malgorzata A. Sobolewska, Chris Done

    We investigate the nature of the soft excess below 1 keV observed in AGN. We use the XMM-Newton data of the low redshift, optically bright quasar, PG 1211+143, and we compare it with the Narrow Line Seyfert 1 galaxy, 1H 0707-495, which has one of the strongest soft excesses seen. We test various ideas for the origin of the soft X-ray excess, including a sepa

  41. Arnab Chatterjee, Bikas K. Chakrabarti

    We study here numerically the behavior of an ideal gas like model of markets having only one non-consumable commodity. We investigate the behavior of the steady-state distributions of money, commodity and total wealth, as the dynamics of trading or exchange of money and commodity proceeds, with local (in time) fluctuations in the price of the commodity. Thes

  42. Kostas Skenderis, Paul K. Townsend

    We use Hamiltonian methods to study curved domain walls and cosmologies. This leads naturally to first order equations for all domain walls and cosmologies foliated by slices of maximal symmetry. For Minkowski and AdS-sliced domain walls (flat and closed FLRW cosmologies) we recover a recent result concerning their (pseudo)supersymmetry. We show how domain-w

  43. Par Arvidsson

    The supergroup OSp(8*|4), which is the superconformal group of (2,0) theory in six dimensions, is broken to the subgroup OSp(4|2)xOSp(4|2) by demanding the invariance of a certain product in a superspace with eight bosonic and four fermionic dimensions. We show that this is consistent with the symmetry breaking induced by the presence of a flat two-dimension

  44. M. Mapelli, S. Sigurdsson, F. R. Ferraro, M. Colpi

    The origin of blue straggler stars (BSS) in globular clusters (GCs) is still not fully understood: they can form from stellar collisions, or through mass transfer in isolated, primordial binaries (PBs). In this paper we use the radial distribution of BSS observed in four GCs (M3, 47Tuc, NGC6752 and omega Cen) to investigate which formation process prevails.

  45. Pearl J. Y. Louis, Makoto Tsubota

    In this work we systematically investigate the condensate properties, superfluid properties and quantum phase transitions in interacting Bose gases trapped in disordered optical potentials. We numerically solve the Bose-Hubbard Hamiltonian exactly for different: (a) types of disorder, (b) disorder strengths, and (c) interatomic interactions. The three types

  46. G. Akemann, P. H. Damgaard, J. C. Osborn, K. Splittorff

    We solve a new chiral Random Two-Matrix Theory by means of biorthogonal polynomials for any matrix size $N$. By deriving the relevant kernels we find explicit formulas for all $(n,k)$-point spectral (mixed or unmixed) correlation functions. In the microscopic limit we find the corresponding scaling functions, and thus derive all spectral correlators in this

  47. Christian Pierre

    An algebraic extended bilinear Hilbert semispace is proposed as being the natural representation space for the algebras of von Neumann.This bilinear Hilbert semispace has a well defined structure given by the representation space of an algebraic general bilinear semigroup over the product of sets of archimedean completions characterized by increasing degrees

  48. Gilles Carbou, Stéphane Labbé, Emmanuel Trélat

    We investigate the problem of controlling the magnetic moment in a ferromagnetic nanowire submitted to an external magnetic field in the direction of the nanowire. The system is modeled with the one dimensional Landau-Lifschitz equation. In the absence of control, there exist particular solutions, which happen to be relevant for practical issues, called trav

  49. Hanno Sahlmann

    As a toy model for the implementation of the diffeomorphism constraint, the interpretation of the resulting states, and the treatment of ordering ambiguities in loop quantum gravity, we consider the Hilbert space of spatially diffeomorphism invariant states for a scalar field. We give a very explicit formula for the scalar product on this space, and discuss

  50. Pyotr N. Ivanshin, Evgenii N. Sosov

    In this article the authors prove strong stability of the set of all Chebyshev centres of the bounded closed subset of the metric space. We endow the set of all compacts of the space $l^n_{\infty}$ with Hausdorff metric and prove that the map which puts in correspondence to each compact of $l^n_{\infty}$ the set of its Chebyshev centres is Lipshitz.

  51. Haruyuki Irie, Kei Tokita

    We studied the mathematical relations between species abundance distributions (SADs) and species-area relationships (SARs) and found that a power-law SAR can be generally derived from a power-law SAD without a special assumption such as the ``canonical hypothesis''. In the present analysis, an SAR-exponent is obtained as a function of an SAD-exponent

  52. A. S. Moskalenko, J. Berakdar, A. A. Prokofiev, I. N. Yassievich

    We calculate ground and excited electron and hole levels in spherical Si quantum dots inside SiO$_2$ in a multiband effective mass approximation. Luttinger Hamiltonian is used for holes and the strong anisotropy of the conduction electron effective mass in Si is taken into account. As boundary conditions for electron and hole wave functions we use continuity

  53. Jiri Adamek, Stefan Milius, Jiri Velebil

    Denotational semantics can be based on algebras with additional structure (order, metric, etc.) which makes it possible to interpret recursive specifications. It was the idea of Elgot to base denotational semantics on iterative theories instead, i.e., theories in which abstract recursive specifications are required to have unique solutions. Later Bloom and E

  54. A. V. Tsiganov

    We introduce elliptic coordinates on the dual space to the Lie algebra e(3$ and discuss the separability of the Clebsch system in these variables. The proposed Darboux coordinates on e^*(3) coincide with the usual elliptic coordinates on the cotangent bundle of the two-dimensional sphere at the zero value of the corresponding Casimir function.

  55. C. Karrasch, T. Hecht, A. Weichselbaum, Y. Oreg

    Transmission phase αmeasurements of many-electron quantum dots (small mean level spacing δ) revealed universal phase lapses by πbetween consecutive resonances. In contrast, for dots with only a few electrons (large δ), the appearance or not of a phase lapse depends on the dot parameters. We show that a model of a multi-level quantum dot with local Coulomb in

  56. Frédéric Blanqui, Jean-Pierre Jouannaud, Albert Rubio

    Termination is a major question in both logic and computer science. In logic, termination is at the heart of proof theory where it is usually called strong normalization (of cut elimination). In computer science, termination has always been an important issue for showing programs correct. In the early days of logic, strong normalization was usually shown by

  57. J. Kiukas, P. Lahti, J. -P. Pellonpää

    Measures with values in the set of sesquilinear forms on a subspace of a Hilbert space are of interest in quantum mechanics, since they can be interpreted as observables with only a restricted set of possible measurement preparations. In this paper, we consider the question under which conditions such a measure extends to an operator valued measure, in the c

  58. Philippe Marmottant, Christophe Raufaste, François Graner

    The plastic flow of a foam results from bubble rearrangements. We study their occurrence in experiments where a foam is forced to flow in 2D: around an obstacle; through a narrow hole; or sheared between rotating disks. We describe their orientation and frequency using a topological matrix defined in the companion paper (Graner et al., preprint), which links

  59. Emmanuel Royer, Jie Wu

    We compute the moments of L-functions of symmetric powers of modular forms at the edge of the critical strip, twisted by the central value of the L-functions of modular forms. We show that, in the case of even powers, it is equivalent to twist by the value at the edge of the critical strip of the symmetric square L-functions. We deduce information on the siz

  60. S. -W. Lin, P. Chang

    We report improved measurements of branching fractions for B -> K pi and B -> pi pi decays based on a data sample of 449 million B Bbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB e^+e^- collider. We also calculate the ratios of partial widths for the decays B -> K pi and pi pi, namely R_c = 1.08 +- 0.06 +- 0.08 and R_n =

  61. Yun Soo Myung, Yong-Wan Kim, Young-Jai Park

    We apply the generalized uncertainty principle to the thermodynamics of a small black hole. Here we have a black hole system with the UV cutoff. It is shown that the minimal length induced by the GUP interrupts the Gross-Perry-Yaffe phase transition for a small black hole. In order to see whether the black hole remnant takes place a transition to a large bla

  62. S. Molchanov, B. Vainberg

    Small diameter asymptotics is obtained for scattering solutions in a network of thin fibers. The asymptotics is expressed in terms of solutions of related problems on the limiting quantum graph. We calculate the Lagrangian gluing conditions at vertices for the problems on the limiting graph. If the frequency of the incident wave is above the bottom of the ab

  63. Kevin Ford

    We give sharp, uniform estimates for the probability that the empirical distribution function for n uniform-[0,1] random variables stays to one side of a given line.

  64. The Belle Collaboration, K. Abe

    We have searched for lepton flavor violating $τ$ decays with a pseudoscalar meson ($η$, $η&#39;$ and $π^0$) using a data sample of 401 fb$^{-1}$ collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. No evidence for these decays is found and we set the following upper limits on the branching fractions: ${\cal{B}}(τ^-\to e^-η) < 9.

  65. H. Nakamura, P. Doe, H. Ejiri, S. R. Elliott

    An ensemble of multi-layer scintillators is discussed as an option of the high-sensitivity detector Mo Observatory Of Neutrinos (MOON) for spectroscopic measurements of neutrino-less double beta decays. A prototype detector MOON-1, which consists of 6 layer plastic-scintillator plates, was built to study the sensitivity of the MOON-type detector. The scintil

  66. Fabio Alencar Mendonca, Rubens Viana Ramos

    The practical realizations of BB84 quantum key distribution protocol using single-photon or weak coherent states have normally presented low efficiency, in the meaning that most bits sent by Alice are not useful for the final key. In this work, we show an optical setup to improve the transmission rate of useful bits putting together two ideas, parallel quant

  67. A. Feoli

    We show that a modified Relativity Principle could explain in a &#34;classical&#34; way the strange correlations of entangled photons. We propose a gedanken experiment with balls and boxes that predicts the same distribution of probability of the Quantum Mechanics in the case of the EPR experiment with a pair of entangled photons meeting a pair of polarizers

  68. T. Gopinath, Anil Kumar

    Hadamard spectroscopy has earlier been used to speed-up multi-dimensional NMR experiments. In this work we speed-up the two-dimensional quantum computing scheme, by using Hadamard spectroscopy in the indirect dimension, resulting in a scheme which is faster and requires the Fourier transformation only in the direct dimension. Two and three qubit quantum gate

  69. Robin P. Sagar, Nicolais L. Guevara

    Shannon entropies of one- and two-electron atomic structure factors in the position and momentum representations are used to examine the behavior of the off-diagonal elements of density matrices with respect to the uncertainty principle and to analyze the effects of electron correlation on off-diagonal order. We show that electron correlation induces off-dia

  70. Per Arne Rikvold

    We explore the complex dynamical behavior of simple predator-prey models of biological coevolution that account for interspecific and intraspecific competition for resources, as well as adaptive foraging behavior. In long kinetic Monte Carlo simulations of these models we find quite robust 1/f-like noise in species diversity and population sizes, as well as

  71. George Parzen

    Electron cooling that results when a bunch of electrons overlaps a bunch of ions , with both bunches moving at the same velocity, may be considered to be an intrabeam scattering process. The process is similar to the usual intrabeam scattering, where the ions scatter from each other and usually results in beam growth. An important difference is that in elect

  72. M. Marklund, P. K. Shukla, L. Stenflo

    A kinetic theory for radiation interacting with sound waves in an ultrarelativistic electron-positron plasma is developed. It is shown that the effect of a spatial spectral broadening of the electromagnetic pulse is to introduce a reduction of the growth rates for the decay and modulational instabilities. Such spectral broadening could be due to a finite pul

  73. A. D. Kondorskiy, L. P. Presnyakov, Yu. Ralchenko

    The possibility of achieving highly selective excitation of low metastable states of hydrogen and helium atoms by using short laser pulses with reasonable parameters is demonstrated theoretically. Interactions of atoms with the laser field are studied by solving the close-coupling equations without discretization. The parameters of laser pulses are calculate

  74. Emmanuel Courtade, Olivier Houde, Jean-François Clément, Philippe Verkerk

    We propose a new geometry of optical lattice for cold atoms, namely a lattice made of a 1D stack of dark ring traps. It is obtained through the interference pattern of a standard Gaussian beam with a counter-propagating hollow beam obtained using a setup with two conical lenses. The traps of the resulting lattice are characterized by a high confinement and a

  75. S. Schippers, E. W. Schmidt, D. Bernhardt, D. Yu

    The photorecombination spectrum of 48Ti18+ was measured employing the merged electron-ion beams technique at a heavy-ion storage ring. The experimental electron-ion collision energy range 0-80 eV comprises all dielectronic recombination (DR) resonances associated with 2s->2p (Delta N =0) core excitations as well as trielectronic recombination (TR) resonances

  76. D. T. Hristopulos, S. N. Elogne

    An explicit optimal linear spatial predictor is derived. The spatial correlations are imposed by means of Gibbs energy functionals with explicit coupling coefficients instead of covariance matrices. The model inference process is based on physically identifiable constraints corresponding to distinct terms of the energy functional. The proposed predictor is c

  77. Lisa M. Hermsen, Scott V. Franklin

    Writing-to-learn initiatives such as Writing Across the Curriculum or Writing in the Disciplines occupy the center of writing programs nationwide. Nevertheless, research to support the core of the writing-to-learn philosophy--that the writing process can facilitate content learning--is, at best, inconclusive. Calls for additional research have noted the impo

  78. S. Jadach, P. Sawicki

    FOAM-2.06 is an upgraded version of FOAM, a general purpose, self-adapting Monte Carlo event generator. In comparison with FOAM-2.05, it has two important improvements. New interface to random numbers lets the user to choose from the three &#34;state of the art&#34; random number generators. Improved algorithms for simplical grid need less computer memory; t

  79. Hailu Luo, Zhongzhou Ren, Weixing Shu, Fei Li

    We study theoretically the effect of ultraslow phase and group velocities in an anisotropic metamaterial. The ultraslow phase propagation is induced by the hyperbolic dispersion relation. While the inherent physics underlying the slow group velocity are collective operations of the frequency and spatial dispersion. We show that a Gaussian wave packet exhibit

  80. Josep Perello, Miquel Montero, Luigi Palatella, Ingve Simonsen

    The electricity market is a very peculiar market due to the large variety of phenomena that can affect the spot price. However, this market still shows many typical features of other speculative (commodity) markets like, for instance, data clustering and mean reversion. We apply the diffusion entropy analysis (DEA) to the Nordic spot electricity market (Nord

  81. Kim Young-Cheol

    This paper introduces a new concept of one-dimensional hologram which represents one line image, and a new kind of display structure using it. This one-dimensional hologram is similar to a superpositioned diffraction lattice. And the interference patterns can be efficiently computed with a simple optical computing structure. This is a Proposal for a new kind

  82. Igor L. Iosilevski, Alexander Yu. Chigvintsev

    Remarkable feature of new first-order phase transitions of gas-liquid gas-crystal types in combination with traditional solid-liquid transition are under consideration in a modified one-component plasma model (OCP) with uniform, but compressible background. Structure and parameters of this phase transition strongly depend on the value of charge number Z. Und

  83. Alexander D. Cronin, Ben McMorran

    We present an electron interferometer based on near-field diffraction from two nanostructure gratings. Lau fringes are observed with an imaging detector, and revivals in the fringe visibility occur as the separation between gratings is increased from 0 to 3 mm. This verifies that electron beams diffracted by nanostructures remain coherent after propagating f

  84. Ashoke Sen

    This article contains a short review of the current status of string theory.

  85. Andrea Alu, Nader Engheta

    Here we discuss the theory and analyze in detail the guidance properties of linear arrays of metamaterial/plasmonic small particles as nano-scale optical nanotransmission lines, including the effect of material loss. Under the assumption of dipolar approximation for each particle, which is shown to be accurate in the geometry of interest here, we develop clo

  86. Sebastiaan Y. T. van de Meerakker, Irena Labazan, Steven Hoekstra, Jochen Küpper

    We report on the production of a pulsed molecular beam of metastable NH ($a ^1Δ$) radicals and present first results on the Stark deceleration of the NH ($a ^1Δ, J=2, MΩ=-4$) radicals from 550 m/s to 330 m/s. The decelerated molecules are excited on the spin-forbidden $A ^3Π\leftarrow a ^1Δ$ transition, and detected via their subsequent spontaneous fluoresce

  87. V. O. Nesterenko, W. Kleinig, J. Kvasil, P. Vesely

    We formulate the self-consistent separable random-phase-approximation (SRPA) method and specify it for Skyrme forces with pairing for the case of axially symmetric deformed nuclei. The factorization of the residual interaction allows to avoid diagonalization of high-rank RPA matrices, which dramatically reduces the computational expense. This advantage is cr

  88. S. Barsov, M. Büscher, M. Hartmann, V. Hejny

    The production of omega-mesons in the pp->pp omega reaction has been investigated with the COSY-ANKE spectrometer for excess energies of 60 and 92MeV by detecting the two final protons and reconstructing their missing mass. The large multipion background was subtracted using an event-by-event transformation of the proton momenta between the two energies. Dif

  89. Jiangyong Jia

    We discussed methods used by the PHENIX to constrain the flow background in the two particle jet correlation. Both the background level and elliptic flow can be reliably decomposed from the jet contribution. We also studied the non-flow contribution to the reaction plane elliptic flow due to dijets. We found the jet bias is negligible in PHENIX, when the rea

  90. Shuji Ishihara, Mikiya Otsuji, Atsushi Mochizuki

    Reaction diffusion systems with Turing instability and mass conservation are studied. In such systems, abrupt decays of stripes follow quasi-stationary states in sequence. At steady state, the distance between stripes is much longer than that estimated by linear stability analysis at a homogeneous state given by alternative stability conditions. We show that

  91. A. C. D. van Enter, W. M. Ruszel

    We present a class of examples of nearest-neighbour, boubded-spin models, in which the low-temperature Gibbs measures do not converge as the temperature is lowered to zero, in any dimension.

  92. F. Dominguez, C. Esebbag, J. Dukelsky

    We study the Richardson equations close to the critical values of the paring strength g_c where the occurrence of divergencies preclude numerical solutions. We derive a set of equations for determining the critical g values and the non-collapsing pair energies. Studying the behavior of the solutions close to the critical points, we develop a procedure to sol

  93. Maryna Nesterenko

    Complete sets of bases of differential invariants, operators of invariant differentiation and Lie determinants of continuous transformation groups acting on the real plane are constructed. As a necessary preliminary, realizations of finite-dimensional Lie algebras on the real plane are revisited.

  94. Thomas Lam, Pavlo Pylyavskyy

    We show that certain differences of products of $P$-partition generating functions are positive in the basis of fundamental quasi-symmetric functions L_α. This result interpolates between recent Schur positivity and monomial positivity results of the same flavor. We study the case of chains in detail, introducing certain ``cell transfer&#39;&#39; operations

  95. Sankaran Viswanath

    We give an elementary combinatorial proof of a special case of a result due to Bazlov and Ion concerning the Fourier coefficients of the Cherednik kernel. This can be used to give yet another proof of the classical fact that for a complex simple Lie algebra, the partition formed by its exponents is dual to that formed by the numbers of positive roots at each

  96. Mahmoud Hesaaraki, Abbas Moameni

    We study the existence of positive radially symmetric solution for the singular $p$-Laplacian Dirichlet problem, $-\bigtriangleup_p u =λ|u|^{p-2} u-γu^{-α}$ where $λ>0,γ>0$ and, $0<α<1$, are parameters and $Ω$, the domain of the equation, is a ball in $\mathbb{R}^N$. By using some variational methods we show that, if $λ$ is contained in some interval, then t

  97. Abbas Moameni

    Mountain pass in a suitable Orlicz space is employed to prove the existence of soliton solutions for a quasilinear Schrödinger equation involving critical exponent in ${\BR}^N$. These equations contain strongly singular nonlinearities which include derivatives of the second order. Such equations have been studied as models of several physical phenomena. The

  98. Abbas Moameni

    We consider the equation $- Δu+V(x)u- k(\Del(|u|^{2}))u=g(x,u), u>0, x \in {\BR}^2,$ where $V:{\BR}^2\to {\BR}$ and $g:{\BR}^2 \times {\BR}\to {\BR}$ are two continuous $1-$periodic functions. Also, we assume $g$ behaves like $\exp (β|u|^4)$ as $|u|\to \infty.$ We prove the existence of at least one weak solution $u \in H^1({\BR}^2)$ with $u^2 \in H^1({\BR}^

  99. Javier Cilleruelo, Melvyn B. Nathanson

    A set A of positive integers is called a perfect difference set if every nonzero integer has an unique representation as the difference of two elements of A. We construct dense perfect difference sets from dense Sidon sets. As a consequence of this new approach, we prove that there exists a perfect difference set A such that A(x) >> x^{\sqrt{2}-1-o(1)}. We a

  100. Marianne Akian, Stephane Gaubert, Cormac Walsh

    A general problem in optimal control consists of finding a terminal reward that makes the value function independent of the horizon. Such a terminal reward can be interpreted as a max-plus eigenvector of the associated Lax-Oleinik semigroup. We give a representation formula for all these eigenvectors, which applies to optimal control problems in which the st