February 2002 arXiv papers — page 16

Lawrence J. Hall, Yasunori Nomura

A realistic SU(3)_C x SU(3)_W unified theory is constructed with a TeV sized extra dimension compactified on the orbifold S_1/Z_2, leaving only the standard model gauge group SU(3)_C x SU(2)_L x U(1)_Y unbroken in the low energy 4D theory. The Higgs doublets are zero modes of bulk SU(3)_W triplets and serve to normalize the hypercharge generator, apparently

Tomaso Belloni, Dimitrios Psaltis, Michiel van der Klis

We study an empirical model for a unified description of the power spectra of accreting neutron stars and black holes. This description is based on a superposition of multiple Lorentzians and offers the advantage that all QPO and noise components are dealt with in the same way, without the need of deciding in advance the nature of each component. This approa

Tiziana Di Matteo, Steven W. Allen, Andrew C. Fabian, Andrew S. Wilson

Chandra X-ray observations of the giant elliptical galaxy M87 resolve the thermal state of the hot interstellar medium into the accretion (Bondi) radius of its central 3 10^9 Msun black hole. We measure the X-ray gas temperature and density profiles and calculate the Bondi accretion rate, Mdot_Bondi \sim 0.1 Msun/yr. The X-ray luminosity of the active nucleu

Sergei Bashinsky, Edmund Bertschinger

We show that the linear dynamics of cosmological perturbations can be described by coupled wave equations, allowing their efficient numerical and, in certain limits, analytical integration directly in position space. The linear evolution of any perturbation can then be analyzed with the Green's function method. Prior to hydrogen recombination, assuming t

W. N. Brandt, D. P. Schneider, X. Fan, M. A. Strauss

We report on exploratory Chandra observations of the three highest redshift quasars known (z = 5.82, 5.99, and 6.28), all found in the Sloan Digital Sky Survey. These data, combined with a previous XMM-Newton observation of a z = 5.74 quasar, form a complete set of color-selected, z > 5.7 quasars. X-ray emission is detected from all of the quasars at levels

Ben Craps, Matthias R. Gaberdiel, Jeffrey A. Harvey

We study D-branes in the bosonic closed string theory whose automorphism group is the Bimonster group (the wreath product of the Monster simple group with Z_2). We give a complete classification of D-branes preserving the chiral subalgebra of Monster invariants and show that they transform in a representation of the Bimonster. Our results apply more generall

Mauro Brigante, Sergio Cacciatori, Dietmar Klemm, Daniela Zanon

We show that the asymptotic dynamics of two-dimensional de Sitter or anti-de Sitter Jackiw-Teitelboim (JT) gravity is described by a generalized two-particle Calogero-Sutherland model. This correspondence is established by formulating the JT model of (A)dS gravity in two dimensions as a topological gauge theory, which reduces to a nonlinear 0+1-dimensional s

Sharmanthie Fernando

We report a three parameter family of solutions for dilaton gravity in 2+1 dimensions with finite mass and finite angular momentum. These solutions are obtained by a compactification of vacuum solutions in 3+1 dimensions with cylindrical symmetry. One class of solutions corresponds to conical singularities and the other leads to curvature singularities.

J. Portoles, P. D. Ruiz-Femenia

We analyse new contributions to the theoretical input in heavy quark sum rules and we show that the general theory of singularities of perturbation theory amplitudes yields the method to handle these specific features. In particular we study the inclusion of heavy quark radiation by light quarks at O(alpha_s^2) and non-symmetric correlators at O(alpha_s^3).

J. D. Harrop, S. N. Taraskin, S. R. Elliott

This paper describes a method for extracting rapidly varying, superimposed amplitude- and frequency-modulated signal components. The method is based upon the continuous wavelet transform (CWT) and uses a new wavelet which is a modification to the well-known Morlet wavelet to allow analysis at high resolution. In order to interpret the CWT of a signal correct

M. Dvornikov, A. Studenikin

The derivation of the quasiclassical Lorentz invariant neutrino spin evolution equation taking into account general types of neutrino non-derivative interactions with external fields is presented. We discuss the constraints on the characteristics of matter and neutrino under which this quasiclassical approach is valid. The application of the obtained equatio

Stefan Immler, Walter H. G. Lewin

We present a review of X-ray observations of supernovae (SNe). By observing the (~0.1-100 keV) X-ray emission from young SNe, physical key parameters such as the circumstellar matter (CSM) density, mass-loss rate of the progenitor and temperature of the outgoing and reverse shock can be derived as a function of time. Despite intensive search over the last ~2

Alejandro Ibarra, Ramon Toldra

We calculate the cosmic ray spectrum of ultra high energy neutralinos that one should expect provided that the observed ultra high energy cosmic rays are produced by the decay of superheavy particles X, M_X>10^{12} GeV, in supersymmetric models. Our calculation uses an extended DGLAP formalism. Forthcoming cosmic ray observatories should be able to detect th

Andrew W. Blain, Ian Smail, R. J. Ivison, J. -P. Kneib

A cosmologically significant population of very luminous high-redshift galaxies has recently been discovered at submm wavelengths. Advances in submm detector technologies have opened this new window on the distant Universe. Here we discuss the properties of the high-redshift submm galaxies, their significance for our understanding of the process of galaxy fo

I. Adagideli, C. W. J. Beenakker

A semiclassical theory is developed for the appearance of an excitation gap in a ballistic chaotic cavity connected by a point contact to a superconductor. Diffraction at the point contact is a singular perturbation in the limit $\hbar\to 0$, which opens up a gap $E_{\rm gap}$ in the excitation spectrum. The time scale $\hbar/E_{\rm gap}\proptoα^{-1}\ln\hbar

Antonio F. Rañada

A phenomenological model is proposed to explain the recent observed cosmological variation of the fine structure constant as an effect of the quantum vacuum, assuming a flat universe with cosmological constant $Λ$ in the cases ($Ω_M, Ω_Λ$) equal to (0.3,0.7) and (1,0). Because of the fourth Heisenberg relation, the lifetime of the virtual pairs of the zero-p

J. Gieraltowski, C. Tannous

Magnetic coupling between Ni_{81}Fe_{19} double thin films separated by an insulating SiO_{2} spacer layer is investigated with structural measurements, cross sectional imaging, magnetization measurements (BH loop) and transport under the conditions of variable spacer thickness ranging from 0 to 5000 Angstroms. We investigate several models to explain the co

Sergio M. C. V. Goncalves

The gravitational collapse of an infinite cylindrical thin shell of generic matter in an otherwise empty spacetime is considered. We show that geometries admitting two hypersurface orthogonal Killing vectors cannot contain trapped surfaces in the vacuum portion of spacetime causally available to geodesic timelike observers. At asymptotic future null infinity

Shigenori Kagiyama, Shunichiro Kumamoto, Akira Minaka, Akihiro Nakamura

The phase structure of hadrons and quark-gluon plasma is investigated by two types of equation of hadron state, namely ideal hadron gas model and the compressible bag model. It is pointed out that, while the ideal gas model produces unrealistic extra hadron phase, the compressible bag model gives an expected and reasonable phase diagram even if rich hadron s

C. Garcia-Recio, J. Nieves, E. Oset

We evaluate widths and shifts of pionic atoms using a theoretical microscopical potential in which the pion decay constant $f_π$ is changed by an in--medium density dependent one ($f_π(ρ)$), predicted by different partial Chiral restoration calculations. We show that the results obtained for shifts and widths are worse than if this modification were not impl

Francisco Santos, Bernd Sturmfels

The class of simplicial complexes representing triangulations and subdivisions of Lawrence polytopes is closed under Alexander duality. This gives a new geometric model for oriented matroid duality.

J. V. Cunha, J. A. S. Lima, N. Pires

We discuss the classical cosmological tests for a large class of FRW type models driven by a decaying vacuum energy density. Analytic expressions for the lookback time, age of the universe, luminosity distance, angular diameter, and galaxy number counts versus redshift are derived and their meaning discussed in detail. It is found that the standard FRW resul

Enke Wang, Xin-Nian Wang

Medium modification of parton fragmentation functions induced by multiple scattering and gluon bremsstrahlung is shown to describe the recent HERMES data in deeply inelastic scattering (DIS) very well, providing the first evidence of $A^{2/3}$-dependence of the modification. The energy loss is found to be $<dE/dL> \approx 0.5$ GeV/fm for a 10-GeV quark in a

R. Delbourgo, M. D. Scadron

Once massless quadratically divergent tadpole diagrams are discarded, because they contain no intrinsic scale, it is possible to convert other divergences into logarithmic form, using partial fraction identities; this includes the case of quadratic divergences, as has been applied to the linear sigma model. However the procedure must be carried out with due

Marco Frasca

Starting from the study of one-dimensional potentials in quantum mechanics having a small distance behavior described by a harmonic oscillator, we extend this way of analysis to models where such a behavior is not generally expected. In order to obtain significant results we approach the problem by a renormalization group method that can give a fixed point H

Jeffrey C. Jackson, Christino Tamon, Tomoyuki Yamakami

We describe a quantum PAC learning algorithm for DNF formulae under the uniform distribution with a query complexity of $\tilde{O}(s^{3}/ε+ s^{2}/ε^{2})$, where $s$ is the size of DNF formula and $ε$ is the PAC error accuracy. If $s$ and $1/ε$ are comparable, this gives a modest improvement over a previously known classical query complexity of $\tilde{O}(ns^

Evan M. Fortunato, Marco A. Pravia, Nicolas Boulant, Grum Teklemariam

We describe a method for improving coherent control through the use of detailed knowledge of the system&#39;s Hamiltonian. Precise unitary transformations were obtained by strongly modulating the system&#39;s dynamics to average out unwanted evolution. With the aid of numerical search methods, pulsed irradiation schemes are obtained that perform accurate, ar

W. P. Smith, J. E. Reiner, L. A. Orozco, S. Kuhr

Detection of a single photon escaping an optical cavity QED system prepares a non-classical state of the electromagnetic field. The evolution of the state can be modified by changing the drive of the cavity. For the appropriate feedback, the conditional state can be captured (stabilized) and then released. This is observed by a conditional intensity measurem

V. I Man&#39;ko, L. Rosa, P. Vitale

The symmetry properties under permutation of tomograms representing the states of a system of identical particles are studied. Starting from the action of the permutation group on the density matrix we define its action on the tomographic probability distribution. Explicit calculations are performed in the case of the two-dimensional harmonic oscillator.

Alec Maassen van den Brink

The book deals with a stochastic formulation of path integration in real time, by rotating the_space_ variables over exp(i pi/4). Preliminary chapters deal with quantum and classical mechanics, probability theory and stochastic calculus, and the conventional approach to path integration through the Trotter product formula. Subsequently, the stochastic formul

Miroljub Dugic

In contradistinction with some plausible statements of the information theory, we point out the possibility of the zero energy quantum information processing. Particularly, we investigate the rate of the entanglement formation in the operation of the quantum &#34;oracles&#34; employing the &#34;quantum parallelism&#34;, and we obtain that the relative maximu

A. D. Jackson, B. Lautrup, P. Johansen, M. Nielsen

We derive analytic expressions for infinite products of random 2x2 matrices. The determinant of the target matrix is log-normally distributed, whereas the remainder is a surprisingly complicated function of a parameter characterizing the norm of the matrix and a parameter characterizing its skewness. The distribution may have importance as an uncommitted pri

M. P. Lorikyan

Performance of the known porous multiwire radiation detectors is stable in the mode of pulsed voltage supply. The results of the study of multiwire porous detector operated at constant voltage supply are presented in this article. It is shown that the detector&#39;s performance is stable, and its spatial resolution $Δx β\pm 60 μm$.

D. R. Entem, R. Machleidt

We calculate the impact of the complete set of two-pion exchange contributions at chiral order four (also known as next-to-next-to-next-to-leading order, N3LO) on peripheral partial waves of nucleon-nucleon scattering. Our calculations are based upon the analytical studies by Kaiser. It turns out that the contribution of order four is substantially smaller t

P. Kammel, V. A. Andreev, D. V. Balin, R. M. Carey

The aim of the MuCap experiment is a 1% measurement of the singlet capture rate Lambda_S for the basic electro-weak reaction mu + p -> n + nu_mu. This observable is sensitive to the weak form-factors of the nucleon, in particular to the induced pseudoscalar coupling constant g_P. It will provide a rigorous test of theoretical predictions based on the Standar

A. Foerster

At the Kaon Spectrometer KaoS at SIS, GSI the production of kaons and antikaons in heavy ion reactions at a beam energy of 1.5 AGeV has been measured for the collision systems Ni+Ni and Au+Au. The K-/K+ ratio is found to be constant for both systems and as a function of impact parameter but the slopes of K+ and K- spectra differ for all impact parameters. Fu

T. C. Awes, A. Bazilevsky, S. Bathe, D. Bucher

In the PHENIX experiment at RHIC, the electro-magnetic calorimeter plays an important role in both the heavy-ion and spin physics programs for which it was designed. In order to measure its performance in the energy range up to 80GeV, a beam test was performed at the CERN-SPS H6 beam line. We describe the beam test and present results on calorimeter performa

D. Bandyopadhyay, C. Bhattacharya, K. Krishan, S. Bhattacharya

The energy spectra of evaporated light charged particles (LCP) $α$, p, d and t have been measured in $7^$Li(47 MeV) + ${24}^$Mg and ${19}^$F(96 MeV)+ ${12}^$C reactions. Both the systems populate the same compound nucleus ${31}^$F at excitation energy E$^*$ ~ 60 MeV. It has been observed that the light particle spectra obtained in Li + Mg reaction follow sta

M. Onorato, A. Osborne, M. Serio, R. Fedele

We study the nonlinear energy transfer around the peak of the spectrum of surface gravity waves by taking into account nonhomogeneous effects. In the narrow-banded approximation the kinetic equation resulting from a nonhomogeneous wave field is a Vlasov-Poisson type equation which includes at the same time the random version of the Benjamin-Feir instability

Oleg Pikhurko

Borsuk&#39;s conjecture states that any bounded set in R^n can be partitioned into n+1 sets of smaller diameter. It is known to be false for all n bigger or equal to 323. Here we show that Borsuk&#39;s conjecture fails in dimensions 321 and 322. (This result has been independently discovered by Hinrichs and Richter.)

G. Lusztig

We show that any two homomorphisms of the alternating group A_5 into E_8 (over the complex numbers) whose images has finite centralizers are conjugate under E_8. This, in conjunction with earlier work of Frey, completes the classification up to G-conjugacy of homomorphisms of A_5 into a simple adjoint algebraic group over the complex numbers.

Mikhail Khovanov

The sequence of rings $H^n, n\ge 0,$ introduced in math.QA/0103190, controls categorification of the quantum sl(2) invariant of tangles. We prove that the center of $H^n$ is isomorphic to the cohomology ring of the (n,n) Springer variety and show that the braid group action in the derived category of $H^n$-modules descends to the Springer action of the symme

Yuri I. Manin

Classical theory of Complex Multiplication (CM) shows that all abelian extensions of a complex quadratic field $K$ are generated by the values of appropriate modular functions at the points of finite order of elliptic curves whose endomorphism rings are orders in $K$. For real quadratic fields, a similar description is not known. However, the relevant (still

Youssef Jabri

We establish an abstract critical point theorem for locally Lipschitz functionals that does not require any compactness condition of Palais-Smale type. It generalizes and unifies three other critical point theorems established in [Jabri-Moussaoui] for $C^{1}$-functionals under slightly stronger assumptions. Our approach uses continuous selections of multival

Youssef Jabri

We adapt a technique of nonsmooth critical point theory developed by Degiovanni-Zani for a semilinear problem involving the Laplacian to the the case of the $p$-Laplacian. We suppose only coercivity conditions on the potential and impose no growth condition of the nonlinearity. The coercivity is obtained using similar nonresonance conditions to [Mawhin-Ward-

Sergey Kudryavtsev

In this paper the detailed classification of three-dimensional exceptional canonical hypersurface singularities which don&#39;t satisfy the condition of well-formedness is given. This result completes the classification of three-dimensional exceptional log canonical hypersurface singularities started in [4] (math.AG 0201025).

Volker Kaibel

Blind and Mani (1987) proved that the entire combinatorial structure (the vertex-facet incidences) of a simple convex polytope is determined by its abstract graph. Their proof is not constructive. Kalai (1988) found a short, elegant, and algorithmic proof of that result. However, his algorithm has always exponential running time. We show that the problem to

Oscar Arratia, Mariano A. del Olmo

Unitary representations of kinematical symmetry groups of quantum systems are fundamental in quantum theory. We propose in this paper its generalization to quantum kinematical groups. Using the method, proposed by us in a recent paper (olmo01), to induce representations of quantum bicrossproduct algebras we construct the representations of the family of stan

J. Kolumban, A. Soos

We use contraction method in probabilistic metric spaces to prove existence and uniqueness of selfsimilar random fractal measures.

Eugene Karolinsky, Alexander Stolin

Jiang-Hua Lu showed that any dynamical r-matrix for the pair $(g,u)$ naturally induces a Poisson homogeneous structure on $G/U$. She also proved that if $g$ is complex simple, $u$ is its Cartan subalgebra and $r$ is quasitriangular, then this correspondence is in fact 1-1. In the present paper we find some general conditions under which the Lu correspondence

Terry Gannon

This paper is primarily intended as an introduction for the mathematically inclined to some of the rich algebraic combinatorics arising in for instance CFT. It is essentially self-contained, apart from some of the background motivation and examples which are included to give the reader a sense of the context. The theory is still a work-in-progress, and empha

Terry Gannon

Weyl groups are ubiquitous, and efficient algorithms for them -- especially for the exceptional algebras -- are clearly desirable. In this paper we provide several of these, addressing practical concerns arising naturally for instance in computational aspects of the study of affine algebras or Wess-Zumino-Witten conformal field theories. We also discuss the

Bert-Jan Nauta, Alejandro Arrizabalaga

We study Chern-Simons number diffusion in a SU(2)-Higgs model with CP-odd dimension-eight operators. We find that the thermal average of the magnitude of the velocity of the Chern-Simons number depends on the direction of the velocity. This implies that the distribution function of the Chern-Simons number will develop an asymmetry. It is argued that this asy

A. Andonov, D. Bardin, S. Bondarenko, P. Christova

In this paper we complete a description of calculation of the one-loop amplitude for e+e- -->f fbar process started in CERN-TH/2001-308. This study is performed within the framework of the project CalcPHEP. Here we add QED subsets of the one-loop diagrams and the soft-photon contribution. The formulae we derived are realized in two independent FORTRAN codes,

John Ellis, Keith Olive, Yudi Santoso

We review constraints on the minimal supersymmetric extension of the Standard Model (MSSM) coming from direct searches at accelerators such as LEP, indirect measurements such as b -> s gamma decay and the anomalous magnetic moment of the muon. The recently corrected sign of pole light-by-light scattering contributions to the latter is taken into account. We

M. Beneke, G. Buchalla, C. Greub, A. Lenz

We compute perturbative QCD corrections to the lifetime splitting between the charged and neutral $B$ meson in the framework of the heavy quark expansion. These next-to-leading logarithmic corrections are necessary for a meaningful use of hadronic matrix elements of local operators from lattice gauge theory. We find the uncertainties associated with the choi

C. E. Aalseth, F. T. Avignone, R. L. Brodzinski, S. Cebrian

The International Germanium Experiment (IGEX) has analyzed 117 mole yr of 76Ge data from its isotopically enriched (86% 76Ge) germanium detectors. Applying pulse-shape discrimination (PSD) to the more recent data, the lower bound on the half-life for neutrinoless double-beta decay of 76Ge is: $T_{1/2}(0ν)> 1.57 \times 10^{25}$ yr (90% C.L.). This corresponds

Yu. V. Pavlov

The nonconformal scalar field is considered in N-dimensional space-time with metric which includes, in particular, the cases of nonhomogeneous spaces and anisotropic spaces of Bianchi type-I. The modified Hamiltonian is constructed. Under the diagonalization of it the energy of quasiparticles is equal to the oscillator frequency of the wave equation. The den

F. I. Mikhail, M. I. Wanas, Gamal G. L. Nashed

The field equations of the new general relativity (NGR) have been applied to an absolute parallelism space having three unknown functions of the radial coordinate. The field equations have been solved using two different schemes. In the first scheme, we used the conventional procedure used in orthodox general relativity. In the second scheme, we examined the

Ali Havare, Taylan Yetkin, Murat Korunur

In this work we solve Dirac equation by using the method of seperation of variables. Then we analyzed the particle creation process. To compute the density number of particles created Bogoliubov transformation technique is used.

Takayuki Tomaru, Toshikazu Suzuki, Shinji Miyoki, Takashi Uchiyama

We report the reduction of the thermal lensing in cryogenic sapphire mirrors, which is planed to be used in the Large scale Cryogenic Gravitational wave Telescope (LCGT) project. We measured three key parameters of sapphire substrate for thermal lensing at cryogenic temperature. They are optical absorption coefficient, thermal conductivity and temperature co

Jim Gray, Alex S. Szalay, Ani R. Thakar, Peter Z. Kunszt

An earlier paper (Szalay et. al. &#34;Designing and Mining MultiTerabyte Astronomy Archives: The Sloan Digital Sky Survey,&#34; ACM SIGMOD 2000) described the Sloan Digital Sky Survey&#39;s (SDSS) data management needs by defining twenty database queries and twelve data visualization tasks that a good data management system should support. We built a databas

Alexander S. Szalay, Jim Gray, Ani R. Thakar, Peter Z. Kunszt

The SkyServer provides Internet access to the public Sloan Digi-tal Sky Survey (SDSS) data for both astronomers and for science education. This paper describes the SkyServer goals and archi-tecture. It also describes our experience operating the SkyServer on the Internet. The SDSS data is public and well-documented so it makes a good test platform for resear

Michael Leuschel, Maurice Bruynooghe

Program specialisation aims at improving the overall performance of programs by performing source to source transformations. A common approach within functional and logic programming, known respectively as partial evaluation and partial deduction, is to exploit partial knowledge about the input. It is achieved through a well-automated application of parts of

David Bremner, Ferran Hurtado, Suneeta Ramaswami, Vera Sacristan

In this paper, we give upper and lower bounds on the number of Steiner points required to construct a strictly convex quadrilateral mesh for a planar point set. In particular, we show that $3{\lfloor\frac{n}{2}\rfloor}$ internal Steiner points are always sufficient for a convex quadrilateral mesh of $n$ points in the plane. Furthermore, for any given $n\geq

Denjoe O&#39;Connor, C. R. Stephens, J. A. Santiago

We consider dimensional crossover for an O(N) model on a d-dimensional layered geometry of thickness L, in the sigma-model limit, using ``environmentally friendly&#39;&#39; renormalization. We show how to derive critical temperature shifts, giving explicit results to one loop. We also obtain expressions for the effective critical exponents delta and beta eff

M. E. J. Newman

The random graph of Erdos and Renyi is one of the oldest and best studied models of a network, and possesses the considerable advantage of being exactly solvable for many of its average properties. However, as a model of real-world networks such as the Internet, social networks or biological networks it leaves a lot to be desired. In particular, it differs f

F. Corberi, A. de Candia, E. Lippiello, M. Zannetti

A thorough numerical investigation of the slow dynamics in the d=1 random field Ising model in the limit of an infinite ferromagnetic coupling is presented. Crossovers from the preasymptotic pure regime to the asymptotic Sinai regime are investigated for the average domain size, the autocorrelation function and staggered magnetization. By switching on an add

Josep Perello, Jaume Masoliver

We prove that a wide class of correlated stochastic volatility models exactly measure an empirical fact in which past returns are anticorrelated with future volatilities: the so-called ``leverage effect&#39;&#39;. This quantitative measure allows us to fully estimate all parameters involved and it will entail a deeper study on correlated stochastic volatilit

R. M. L. Evans, M. D. Haw

We examine the geometry of the spaces between particles in diffusion-limited cluster aggregation, a numerical model of aggregating suspensions. Computing the distribution of distances from each point to the nearest particle, we show that it has a scaled form independent of the concentration phi, for both two- (2D) and three-dimensional (3D) model gels at low

G. Viliani, E. Duval, L. Angelani

Numerical simulation is employed to study dynamical heterogeneities in model harmonic glasses whose atoms interact via three variants of the Lennard-Jones potential (monoatomic full Lennard-Jones, soft spheres, binary mixture). Heterogeneities are observed to exist in all three kinds of glasses, and in some cases they are observed to depend on temperature. T

Gerald Paul, H. Eugene Stanley

The incipient infinite cluster appearing at the bond percolation threshold can be decomposed into singly-connected ``links&#39;&#39; and multiply-connected ``blobs.&#39;&#39; Here we decompose blobs into objects known in graph theory as 3-blocks. A 3-block is a graph that cannot be separated into disconnected subgraphs by cutting the graph at 2 or fewer vert

R. Everaers, A. Milchev, V. Yamakov

We use large scale Monte Carlo simulations to test scaling theories for the electrostatic persistence length $l_e$ of isolated, uniformly charged polymers with Ðintrachain interactions in the limit where the screening length $κ^{-1}$ exceeds the intrinsic persistence length of the chains. Our simulations cover a significantly larger part of the parameter spa

E. G. Moshopoulou, K. Prokes, E. Garcia-Matres, P. G. Pagliuso

We present neutron diffraction measurements in high magnetic fields (0 to 14.5 T) and at low temperatures (2.5, 2.3, 0.77 and 0.068 K) on single crystals of the tetragonal heavy fermion antiferromagnet Ce2RhIn8. For B//[110] the field dependence of selected magnetic and nuclear reflections reveals that the material undergoes several transitions, the temperat

Hans A. Weidenmueller

In two recent papers, O. Entin-Wohlman et al. studied the question: ``Which physical information is carried by the transmission phase through a quantum dot?&#39;&#39; In the present paper, this question is answered for an islolated Coulomb-blockade resonance and within a theoretical model which is more closely patterned after the geometry of the actual exper

C. Pinettes, B. Canals, C. Lacroix

The stability of the disordered ground state of the classical Heisenberg pyrochlore antiferromagnet is studied within extensive Monte Carlo simulations by introducing an additional exchange interaction $J&#39;$ that interpolates between the pyrochlore lattice ($J&#39;=0$) and the face-centered cubic lattice ($J&#39;=J$). It is found that for $J&#39;/J$ as lo

A. Fledderjohann, K. -H. Muetter

The ground state properties of the Shastry-Sutherland model in the presence of an external field are investigated by means of variational states built up from unpaired spins (monomers) and singlet pairs of spins (dimers). The minimum of the energy is characterized by specific monomer-dimer configurations, which visualize the magnetic order in the sectors wit

M. Elhajal, B. Canals, C. Lacroix

Due to the particular geometry of the kagomé lattice, it is shown that antisymmetric Dzyaloshinsky-Moriya interactions are allowed and induce magnetic ordering. The symmetry of the obtained low temperature magnetic phases are studied through mean field approximation and classical Monté Carlo simulations. A phase diagram relating the geometry of the interacti

E. B. Sonin

In superconducting ferromagnets the equilibrium domain structure is absent in the Meissner state, but appears in the spontaneous vortex phase (the mixed state in zero external magnetic field), though with a period, which can essentially exceed that in normal ferromagnets. Metastable domain walls are possible even in the Meissner state. The domain walls creat

Indrani Bose

In this review, we give an introduction to the structural and functional properties of the biological networks. We focus on three major themes: topology of complex biological networks like the metabolic and protein-protein interaction networks, nonlinear dynamics in gene regulatory networks and in particular the design of synthetic genetic networks using the

Nobuhiko Hayashi, Yusuke Kato

The elementary vortex pinning potential is studied in a chiral p-wave superconductor with a pairing d=z(k_x + i k_y) on the basis of the quasiclassical theory of superconductivity. An analytical investigation and numerical results are presented to show that the vortex pinning potential is dependent on whether the vorticity and chirality are parallel or antip

Patrick C. McGuire, Henrik Bohr, John W. Clark, Robert Haschke

We study the diversity of complex spatio-temporal patterns in the behavior of random synchronous asymmetric neural networks (RSANNs). Special attention is given to the impact of disordered threshold values on limit-cycle diversity and limit-cycle complexity in RSANNs which have `normal&#39; thresholds by default. Surprisingly, RSANNs exhibit only a small rep

Arjun Berera, David Hochberg

The dynamic renormalization group (RG) is used to study the large-distance and long-time limits of viscous and resistive incompressible magnetohydrodynamics subject to random forces and currents. The scale-dependent viscosity and magnetic resistivity are derived and used for carrying out RG-improved perturbation theory. This is applied to derive both the asy

Tal Alexander

This is a pedagogical review of recent results on the interactions of central massive black holes with stars very near them, focused on the black hole in the center of the Milky Way. Table of contents: [1] Introduction [2] Stellar dynamics near a black hole [2.1] Physical scales [2.2] A relaxed stellar system around a MBH [3] The stellar collider in the Gala

Piero Ranalli, Andrea Comastri, Giancarlo Setti

Radio and far infrared luminosities of star forming galaxies follow a tight linear relation. Making use of BeppoSAX and ASCA observations of a well-defined sample of star forming galaxies, we argue that a tight linear relation holds between the 2-10 keV X-ray luminosity and both the radio and far infrared ones. It is suggested that the hard X-ray emission is

Letizia Stanghellini

This review contains: (1) the scientific motivations for studying Planetary Nebulae in the Magellanic Clouds; (2) a review of this field of study, from the origins to the most recent results, focusing on the papers that have been published since the last IAU Symposium on Planetary Nebulae; (3) a review of the Hubble contribution to the field, from the early

J. Christopher Howk, Blair D. Savage, Kenneth R. Sembach, Charles G. Hoopes

We report Far Ultraviolet Spectroscopic Explorer (FUSE) observations of interstellar O VI absorption in the halo of the Milky Way towards 12 early-type stars in the Large Magellanic Cloud (LMC) and 11 in the Small Magellanic Cloud (SMC). The mean column densities of O VI associated with the Galactic halo towards the LMC and SMC are log<N(OVI)> = 14.52(+0.10,

Jay M. Pasachoff, Bryce A. Babcock, Kevin D. Russell, Daniel B. Seaton

As a part of a study of the cause of solar coronal heating, we searched for high-frequency (~1 Hz) intensity oscillations in coronal loops in the [Fe XIV] coronal green line. We summarize results from observations made at the 11 August 1999 total solar eclipse from Ramnicu-Valcea, Romania, through clear skies. We discuss the image reduction and analysis thro

Adam P. Showman, Tristan Guillot

We examine the properties of the atmospheres of extrasolar giant planets at orbital distances smaller than 0.1 AU from their stars. We show that these ``51Peg b-like&#39;&#39; planets are rapidly synchronized by tidal interactions, but that small departures from synchronous rotation can occur because of fluid-dynamical torques within these planets. Previous

Tristan Guillot, Adam P. Showman

About one-quarter of the extrasolar giant planets discovered so far have orbital distances smaller than 0.1 AU. These ``51Peg b-like&#39;&#39; planets can now be directly characterized, as shown by the planet transiting in front the star HD209458. We review the processes that affect their evolution. We apply our work to the case of HD209458b, whose radius ha

Sheila J. Kannappan, Daniel G. Fabricant, Charles B. Hughes

We discuss the design of an inexpensive, high-throughput CCD spectrograph for a small telescope. By using optical fibers to carry the light from the telescope focus to a table-top spectrograph, one can minimize the weight carried by the telescope and simplify the spectrograph design. We recently employed this approach in the construction of IntroSpec, an ins

E. van der Swaluw, A. Achterberg, Y. A. Gallant, T. P. Downes

Hydrodynamical simulations are presented of a pulsar wind emitted by a supersonically moving pulsar. The pulsar moves through the interstellar medium or, in the more interesting case, through the supernova remnant created at its birth event. In both cases there exists a three-fold structure consisting of the wind termination shock, contact discontinuity and

James Chiang

Using a geometry consisting of a hot central Comptonizing plasma surrounded by a thin accretion disk, we model the optical through hard X-ray spectral energy distributions of the type 1 Seyfert galaxies NGC 3516 and NGC 7469. As in the model proposed by Poutanen, Krolik, & Ryde for the X-ray binary Cygnus X-1 and later applied to Seyfert galaxies by Zdziarsk

F. A. Aharonian, A. A. Belyanin, E. V. Derishev, V. V. Kocharovsky

We find the general requirements, set by classical electrodynamics, to the sources of extremely high-energy cosmic rays (EHECRs). It is shown that the parameters of EHECR accelerators are strongly limited not only by the particle confinement in large-scale magnetic field or by the difference in electric potentials (generalized Hillas criterion), but also by

Robert A. Benjamin, Evan D. Skillman, Derck P. Smits

We consider the effect of optical depth of the 2 ^{3}S level on the nebular recombination spectrum of He I for a spherically symmetric nebula with no systematic velocity gradients. These calculations, using many improvements in atomic data, can be used in place of the earlier calculations of Robbins. We give representative Case B line fluxes for UV, optical,

L. J. King, D. I. Clowe, C. Lidman, P. Schneider

We present the first detection of weak gravitational shear at infrared wavelengths, using observations of the lensing cluster Abell 1689, taken with the SofI camera on the ESO-NTT telescope. The imprint of cluster lenses on the shapes of the background galaxy population has previously been harnessed at optical wavelengths, and this gravitational shear signal

M. Rheinhardt, U. Geppert

In the presence of a strong magnetic field and under conditions as realized in the crust and the superfluid core of neutron stars the Hall--drift dominates the field evolution. We show by a linear analysis that for a sufficiently strong large--scale background field depending at least quadratically on position in a plane conducting slab an instability occurs

Veronica Cocco, Francesco Longo, Marco Tavani

In this paper (Paper II) we complete our discussion on the results of a comprehensive GEANT simulation of the scientific performance of the AGILE Gamma-Ray Imaging Detector (GRID), operating in the 30 MeV - 50 GeV energy range in an equatorial orbit of height near 550 km. Here we focus on the on-board Level-2 data processing and discuss possible alternative

Francesco Longo, Veronica Cocco, Marco Tavani

We present in this paper the results of a comprehensive GEANT simulation of the Gamma-Ray Imaging Detector (GRID) being developed for the AGILE space astrophysics mission. The GRID is designed to be sensitive in the 30 MeV - 50 GeV energy range, with excellent imaging and timing capabilities, and with a very large field-of-view (~3 sr). In this paper (Paper

Carlotta Pittori, Marco Tavani

We present the Agile REconstruction Method (AREM) for gamma-ray (30 MeV - 50 GeV) direction reconstruction applicable to high-resolution Silicon Tracker detectors in space. It can be used in a &#34;fast mode&#34;, independently of Kalman filters techniques, or in an &#34;optimized mode&#34;, including Kalman filter algorithms for track identification. AREM c