February 1999 arXiv papers — page 9

Debashish Chowdhury, Dietrich Stauffer, Reinhard Strey, ;

From extensive Monte Carlo simulations of a Larson model of perfectly periodic heteropolymers (PHP) in water a striking stiffening is observed as the period of the alternating hydrophobic and hydrophilic blocks is shortened. At short period and low temperature needle-like conformations are the stable conformation. As temperature is increased thermal fluctuat

A. Andrianov, F. Cannata, M. Ioffe, D. Nishnianidze

We study a complex intertwining relation of second order for Schroedinger operators and construct third order symmetry operators for them. A modification of this approach leads to a higher order shape invariance. We analyze with particular attention irreducible second order Darboux transformations which together with the first order act as building blocks. F

E. Gabrielli, V. A. Ilyin, B. Mele

We consider the possibility of studying anomalous contributions to the gamma-gamma-H and Z-gamma-H vertices through the process e-gamma--> e-H at future e-gamma linear colliders, with Sqrt(S)=500-1500 GeV. We make a model independent analysis based on SU(2)xU(1) invariant effective operators of dim=6 added to the standard model lagrangian. We consider a ligh

R. F. Bishop, D. J. J. Farnell, J. B. Parkinson

We present new and exact ``sign rules'' for various spin-s anisotropic spin-lattice models. It is shown that, after a simple transformation which utilizes these sign rules, the ground-state wave function of the transformed Hamiltonian is positive-definite. Using these results exact statements for various expectation values of off-diagonal operators are prese

C. Murali, J. Dubinski

We discuss how to use tidal streams from globular clusters to measure the mass distribution of the Milky Way. Recent proper motion determinations for globular clusters from plate measurements and Hipparcos astrometry provide several good candidates for Galactic mass determinations in the intermediate halo, far above the Galactic disk, including Pal 5, NGC 41

S. V. Goloskokov

We calculate the cross section and the $A_{ll}$ asymmetry of the diffractive vector meson leptoproduction for a simple model of the pomeron coupling with the proton. It is found that the sensitivity of the spin--dependent cross section of the diffractive $J/Ψ$ production to the pomeron coupling structure is rather weak. The conclusion is made that it will be

E. M. Chudnovsky, X. Martinez-Hidalgo

The ground state tunnel splitting for the biaxial spin model in the magnetic field, H = -D S_{x}^2 + E S_{z}^2 - g μ_B S_z H_z, has been investigated using an instanton approach. We find a new type of spin instanton and a new quantum interference phenomenon associated with it: at a certain field, H_2 = 2SE^{1/2}(D+E)^{1/2}/(g μ_B), the dependence of the tunn

Ch. Kopper, V. F. Mueller

The proof given in the paper was incomplete due to an omission in the proof of Lemma 2. A corrected and improved version of the paper is in arXiv:0902.2486.

A. V. Belitsky

We unravel the structure of the spectrum of the anomalous dimensions of the quark-gluon twist-3 operators which are responsible for the multiparton correlations in hadrons and enter as a leading contribution to several physical cross sections. The method of analysis is bases on the recent finding of a non-trivial integral of motion for the corresponding Hami

E. Friedman, A. Gal

Using optical potentials fitted to a comprehensive set of strong interaction level shifts and widths in $K^-$ atoms, we predict that the $K^-$ atomic levels which are inaccessible in the atomic cascade process are generally narrow, spanning a range of widths about 50 - 1500 keV over the entire periodic table. The mechanism for this narrowing is different fro

S. Ishikawa

Three-nucleon forces have been considered to be one possibility to resolve the well known discrepancy between experimental values and theoretical calculations of the nucleon analyzing power in low energy nucleon-deuteron scattering. In this paper, we investigate possible effects of two-pion exchange three-nucleon forces on the analyzing power and the differe

V. Berezinsky, G. Fiorentini, M. Lissia

The He3 abundance is not constrained by helioseismic data. Mixing of He3 inside the solar core by processes not included in the solar standard model (SSM) has been recently proposed as possible solution to the solar neutrino problem. We have performed a model independent analysis of solar neutrino fluxes using practically arbitrary He3 mixing. In addition, w

S. Esposito

Collective interactions of a beam of neutrinos/antineutrinos traversing a dense magnetized plasma of electrons/positrons, protons and neutrons are studied with particular reference to the case of a Supernova. We find that the ponderomotive force exerted by neutrinos gives, contrary to expectations, a negligible contribution to the revival of the shock for a

Conor Houghton, Patrick Irwin, A. J. Mountain

The metric on the moduli space of charge (2,1) SU(3) Bogomolny-Prasad-Sommerfield monopoles is calculated and investigated. The hyperKahler quotient construction is used to provide an alternative derivation of the metric. Various properties of the metric are derived using the hyperKahler quotient construction and the correspondence between BPS monopoles and

Toshinobu Takagi, Nobuo Arimoto, Vladas Vansevicius

A spectral evolution model of galaxies that includes both stellar and dust effects is newly built. xApplying the model to 22 nearby starburst galaxies, we have shown that far infrared luminosity of galaxies helps to break the age-dustiness degeneracy. We have derived a unique solution of age and the dustiness for each starburst galaxy. The resulting starburs

S. Rai Choudhury, Naveen Gaur, Abhinav Gupta

Rare B decays provides an opportunity to probe for new physics beyond the standard model. the effective Hamiltonian for the decay $b \to s l^+ l^-$ predicts the characteristic polarization for the final state lepton. Lepton polarization has, in addition to a longitudinal component $P_L$, two orthogonal components $P_T$ and $P_N$ lying in and perpendicular to

Hiroaki Nishioka, Kazuhiro Yamamoto

A theoretical formulation for the two-point correlation function on a light-cone is developed in the redshift space. On the basis of the previous work by Yamamoto & Suto (1999), in which a theoretical formula for the two-point correlation function on a light-cone has been developed in the real space, we extend it to the formula in the redshift space by takin

Toby Falk

In the MSSM, the assumptions of a common sfermion mass parameter m_0 and a common gaugino mass parameter m_1/2, along with the requirements from radiative electroweak symmetry breaking, lead to relatively large values of the Higgs mixing parameter mu, and consequently to a gaugino-like lightest neutralino. Lifting the requirement that the Higgs mass paramete

Kentaro Hori

We show that the transformation of D-branes under T-duality on four-torus is represented by Nahm transform of instantons. The argument for this allows us to generalize Nahm transform to the case of orthogonal and symplectic gauge groups as well as to instantons on Z_2 orbifold of four-torus. In addition, we identify the isomorphism of K-theory groups that re

V. V. Ulyanov, O. B. Zaslavskii

Spin coherent states play a crucial role in defining QESM (quasi-exactly solvable models) establishing a strict correspondence between energy spectra of spin systems and low-lying quantum states for a particle moving in a potential field of a certain form. Spin coherent states are also used for finding the Wigner-Kirkwood expansion and quantum corrections to

E. Scapparone

The most important underground detectors addressing Cosmic Ray physics are described, with a special emphasis on the description of the used technology.

S. Gov, S. Shtrikamn, H. Matzner

We use covariance and dimensional analysis to find expressions for the discontinuity of the potential and normal electric field across a flat surface with multipolar charge surface density in vacuum.

Nadejda L. Cherkas

In a frame of quasi-crystal approximation the dispersion equations are obtained for the wave vector of a coherent electromagnetic wave propagating in a media which contains a random set of parallel dielectric cylinders with possible overlapping. The results are compared with that for the case when a regularity at the cylinder placement exists.

Martin van Hecke, Cornelis Storm, Wim van Saarloos

We study the coupled complex Ginzburg-Landau (CGL) equations for traveling wave systems in the regime where sources and sinks separate patches of left and right-traveling waves. We show that sources and sinks are the important coherent structures that organize much of the dynamical properties of traveling wave systems. We present in detail the framework to a

K. Zajac, L. Prochniak, K. Pomorski, S. G. Rohozinski

Quadrupole excitations of even-even Ru and Pd isotopes are described within microscopic approach based on the general collective Bohr model which includes the effect of coupling with the pairing vibrations. The excitation energies and E2 transition probabilities observed in 104-114Ru and 106-110Pd are reproduced in the frame of the calculation containing no

J. A. Templon

I present the case for studying the nature of short-range internucleon interactions with electron-scattering experiments on few-body nuclear targets. I first review what electron-scattering studies have unearthed about the nature of the interactions between nucleons in nuclei at small separation. Special consideration is given to a couple of recent experimen

Alexander Yu. Vlasov

In the comment to the article by J.Baez and K.Krasnov (hep-th/9703112) are discussed some topics related with application of certain constructions to non-trivial principal bundles.

Ch. Kopper

We study the infrared behaviour of the two-dimensional Euclidean O(N) nonlinear sigma-Model with a suitable ultraviolet cutoff. It is proven that for a sufficiently large (but finite!) number N of field components the model is massive and thus has exponentially decaying correlation functions. We use a representation of the model with an interpolating bosonic

M. Boiti, F. Pempinelli, A. Pogrebkov, B. Prinari

Potentials of the nonstationary Schrödinger operator constructed by means of $n$ recursive Bäcklund transformations are studied in detail. Corresponding Darboux transformations of the Jost solutions are introduced. We show that these solutions obey modified integral equations and present their analyticity properties. Generated transformations of the spectral

G. W. Patrick, R. M. Roberts

We show that, given a certain transversality condition, the set of relative equilibria $\mcl E$ near $p_e\in\mcl E$ of a Hamiltonian system with symmetry is locally Whitney-stratified by the conjugacy classes of the isotropy subgroups (under the product of the coadjoint and adjoint actions) of the momentum-generator pairs $(μ,ξ)$ of the relative equilibria.

Kyungho Oh, Radu Tatar

We consider four dimensional supersymmetric gauge field theories from brane configurations with the matter content given by semi-infinite D4 branes ending on both sides of NS branes. In M theory configuration, we discuss the splitting of the M5 brane into infinite cylindrical M5 branes (which decouple) and transversal M5 brane. The splitting condition appear

Eric R. Sharpe

In this paper we describe how Grothendieck groups of coherent sheaves and locally free sheaves can be used to describe type II D-branes, in the case that all D-branes are wrapped on complex varieties and all connections are holomorphic. Our proposal is in the same spirit as recent discussions of K-theory and D-branes; within the restricted class mentioned, G

Gerald V. Dunne

Lectures at the 1998 Les Houches Summer School: Topological Aspects of Low Dimensional Systems. These lectures contain an introduction to various aspects of Chern-Simons gauge theory: (i) basics of planar field theory, (ii) canonical quantization of Chern-Simons theory, (iii) Chern-Simons vortices, and (iv) radiatively induced Chern-Simons terms.

Jose A. Magpantay

Using the recently proposed non-linear gauge condition, we show the area law behavior of the Wilson loop and the linear dependence of the instantaneous gluon propagator. The field configurations responsible for confinement are those in the non-linear sector of the gauge-fixing condition (the linear sector being the Coulomb gauge). The non-linear sector is ac

Ichiro Oda

It is shown in a quantum-mechanically exact manner that a supersymmetric and $κ$-symmetric D-string action in a general type IIB supergravity background is transformed to a form of the type IIB Green-Schwarz superstring action with the SL(2,Z) covariant tension through an S-duality transformation. This result precisely proves a conjecture mentioned previousl

G. K. Leontaris, N. D. Tracas

Motivated by the fact that the string scale can be many orders of magnitude lower than the Planck mass, we investigate the required modifications in the MSSM $β$--functions in order to achieve intermediate ($10^{10-13}$GeV) scale unification, keeping the traditional logarithmic running of the gauge couplings. We present examples of string unified models with

V. Dmitrašinović

We show that, as a consequence of fixing f_π= 93 MeV: (1) a bound state pole in the J^P = 1^- scattering amplitude of the ENJL model exists for arbitrarily weak (positive) vector coupling G_2 so long as the constituent quark mass is sufficiently large; (2) there is a bound state for any quark mass when G_2 \geq 0.6/(8 f_π^2); (3) this bound state becomes mas

Johann Rafelski, Jean Letessier

Abundances and $m_\bot$-spectra of strange and other hadronic particles emanating from central 158-200 A GeV reactions between nuclei are found to originate from a thermally equilibrated, deconfined source in chemical non-equilibrium. Physical freeze-out parameters and physical conditions (pressure, specific energy, entropy, and strangeness) are evaluated. F

John Ellis, S. Lola, D. V. Nanopoulos

We discuss leptogenesis in the light of indications of neutrino masses and mixings from Super-Kamiokande and other data on atmospheric neutrinos, as well as the solar neutrino deficit. Neutrino masses and mixings consistent with these data may produce in a natural and generic way a lepton asymmetry that is suffient to provide the observed baryon asymmetry, a

Massimo Pietroni

The formation of topological defects in a second order phase transition in the early universe is an out-of-equilibrium process. Condensed matter experiments seem to support Zurek's mechanism, in which the freezing of thermal fluctuations close to the critical point (critical slowing down) plays a crucial role. We discuss how this picture can be extrapola

N. Brambilla, A. Vairo

We review the present knowledge on the heavy quark interaction. The framework is the NRQCD effective theory and the interaction is expressed in terms of Wilson loop chromoelectric and chromomagnetic insertions.

V. V. Anisovich, L. G. Dakhno, D. I. Melikhov, V. A. Nikonov

We study the reactions $γ^*(Q^2)p\toρ^0 p$ and $γ^*(Q^2)p\toγ^*(Q^2) p$ at large Q^2 and $W^2/Q^2$ and small momentum transfer, $κ^2_\perp$, to the nucleon where the pomeron exchange dominates. At large Q^2 the virtual photon selects a hard $q\bar q$ pair, thus selecting the hard pomeron component (the BFKL pomeron). The amplitudes for both transverse and lo

K. Kimura, A. Takamura

Under the assumption that the neutrinos are Majorana particles we study how the lepton mass matrices can be transformed into the simple form which has the same physical quantities by removing redundant parameters. We propose the exact parametrization of the lepton mass matrices which reflects the small nu_e-nu_mu mixing and the large nu_mu-nu_tau mixing. The

A. I. Sanda

What do we know about CPT symmetry? We conclude that the direcrt measurement of CPT violation leads to a result that CPT violation force is limited to about 30% of CP violating forces. The best test of CPT symmetry is to see if theoretical prediction for the phase of eta_{+-} and eta_{00} agree with experiments. We discuss uncertainties associated with this

Robert G. Edwards, Urs M. Heller, Rajamani Narayanan

The low-lying spectrum of the Dirac operator is predicted to be universal, within three classes, depending on symmetry properties specified according to random matrix theory. The three universal classes are the orthogonal, unitary and symplectic ensemble. Lattice gauge theory with staggered fermions has verified two of the cases so far, unitary and symplecti

The OPAL Collaboration, G. Abbiendi et al

The structure of both quasi-real and highly virtual photons is investigated using the reaction e+e- -> e+e-mu+mu-, proceeding via the exchange of two photons. The results are based on the complete OPAL dataset taken at e+e- centre-of-mass energies close to the mass of the Z boson. The QED structure function F_2^gamma and the differential cross-section dsigdx

D. Glenzinski

In 1997 each LEP experiment collected approximately $55 {pb}^{-1}$ of data at a center-of-mass energy of 183 GeV. These data yield a sample of candidate $e^+e^- \to W^+W^-$ events from which the mass of the W boson, M_W, is measured. The preliminary LEP combined result, including data taken at $\roots = 161$ and 172 GeV and assuming the Standard Model relati

Bozhidar Z. Iliev

We investigate connections between pairs of (pseudo-)Riemannian metrics whose sum is a (tensor) product of a covector field with itself. A bijective mapping between the classes of Euclidean and Lorentzian metrics is constructed as a special result. The existence of such maps on a differentiable manifold is discussed. Similar relations for metrics of arbitrar

Mark D. Roberts

Recently it has been argued that autocatalytic theory could be applied to the origin of culture. Here possible application to a theory of meaning in the philosophy of language, called radical interpretation, is commented upon and compared to previous applications.

Miodrag L. Kulic, Oleg V. Dolgov

Tunneling and point contact spectroscopy show clear phonon features and together with optic measurements give strong support that the electron-phonon interaction (EPI) is large in HTS oxides. Strong correlations in HTS oxides renormalize the EPI (and interaction with impurities) so that the forward scattering peak (FSP) develops for small hole doping δ<<1. T

Anders W. Sandvik, David K. Campbell

We study the spin-Peierls transition in a Heisenberg spin chain coupled to optical bond-phonons. Quantum Monte Carlo results for systems with up to N=256 spins show unambiguously that the transition occurs only when the spin-phonon coupling alpha exceeds a critical value alpha_c. Using sum rules, we show that the phonon spectral function has divergent (for i

Cecilia Clementi, Michele Vendruscolo, Amos Maritan, Eytan Domany

We studied the possibility to approximate a Lennard Jones interaction by a pairwise contact potential. First we used a Lennard-Jones potential to design off-lattice, protein-like heteropolymer sequences, whose lowest energy (native) conformations were then identified by Molecular Dynamics. Then we turned to investigate whether one can find a pairwise contact

Cecilia Clementi, Paolo Carloni, Amos Maritan

Fundamental questions about the role of the quaternary structures are addressed using a statistical mechanics off-lattice model of a dimer protein. The model, in spite of its simplicity, captures key features of the monomer-monomer interactions revealed by atomic force experiments. Force curves during association and dissociation are characterized by sudden

Anders W. Sandvik

A cluster update (the ``operator-loop&#39;&#39;) is developed within the framework of a numerically exact quantum Monte Carlo method based on the power series expansion of exp(-BH) (stochastic series expansion). The method is generally applicable to a wide class of lattice Hamiltonians for which the expansion is positive definite. For some important models t

G. G. Sergeeva

We discuss the scenario of two-step magnetic ordering in layered high temperature superconductors after charge ordering. As the temperature decreases, the transition from 3D Heisenberg spin behavior to 2D XY coupling of the Cu spins occurs at Berezinskii-Kosterlitz-Thouless temperature in dielectric stripes. Further temperature decreasing leads to the 3D spi

Marcus Mueller

Computer simulation studies on the miscibility behavior and single chain properties in binary polymer blends are reviewed. We consider blends of various architectures in order to identify important architectural parameters on a coarse grained level and study their qualitative consequences for the miscibility behavior. The phase diagram, the relation between

Clement Sire

In this paper, we study the dynamics of a random walker diffusing on a disordered one-dimensional lattice with random trappings. The distribution of escape probabilities is computed exactly for any strength of the disorder. These probabilities do not display any multifractal properties contrary to previous numerical claims. The explanation for this apparent

T. Lorenz, A. Kaeufler, Y. Luo, M. Moske

Permalloy (Py:Ni81Fe19) exhibits an anisotropic magnetoresistance (AMR) which is very often used to read magnetic signals from storage devices. Py-films of thickness 20nm were prepared by dc-magnetron sputtering in a magnetic field onto thermally oxidized Si-wafers and annealed ex situ at temperatures up to 1000K in order to investigate the dependence of the

Jun-ichi Igarashi, Manabu Takahashi, Tatsuya Nagao

A three-body scattering theory previously proposed by one of the present authors is developed to be applied to the saturated ferromagnetic state in the two-dimensional Hubbard model. The single-particle Green&#39;s function is calculated by taking account of the multiple scattering between two electrons and one hole. Several limiting cases are discussed and

Roland R. Netz, H. Orland

A field theory is presented for particles which interact via Coulomb and hard-core potentials. We apply the method to the one-component plasma (OCP) with hard cores, consisting of identical particles of fixed charge and diameter in a neutralizing background, and the symmetric two-component plasma (TCP) with hard cores, consisting of equal numbers of positive

Romualdo Pastor-Satorras

We study the ballistic adsorption of a polydisperse mixture of spheres onto a line. Within a mean-field approximation, the problem can be analytically solved by means of a kinetic equation for the gap distribution. In the mean-field approach, the adsorbed substrate as approximated as composed by {\em effective} particles with the {\em same} size, equal to th

Debasis Dan, Mangal. C. Mahato, A. M. Jayannavar

We study the mobility of an overdamped particle in a periodic potential tilted by a constant force. The mobility exhibits a stochastic resonance in inhomogeneous systems with space dependent friction coefficient. The result indicates that the presence of oscillating external field is not essential for the observability of stochastic resonance, at least in th

Keita Kishigi, Yasumasa Hasegawa, Mitake Miyazaki

The effects of the Zeeman term on the de Haas-van Alphen oscillation is studied in the magnetic breakdown system. We find that the amplitude of the oscillation with the frequencies of $f_β + f_α$ and $f_β + 2f_α$ are enhanced by the Zeeman term, while they are expected to be reduced in the semiclassical theory. A possible interpretation of the experiments in

M. Sigrist, D. Agterberg, A. Furusaki, C. Honerkamp

The symmetry of the superconducting phase of Sr2RuO4 is identified as the odd-parity pairing state d(k)=\hat{z}(k_x \pm i k_y) based on recent experiments. The experimental evidence for the so-called orbital dependent superconductivity leads to a single-band description of superconductivity based on spin fluctuation mechanism. It is shown that the state \hat

Hyok-Jon Kwon

We investigate a zero-temperature itinerant antiferromagnetic transition where the fermions possess a d-wave gap. This problem pertains to both the nodal liquid insulating phase and the d-wave superconducting phase of the underdoped cuprates. We find that a non-trivial quantum phase transition exists, and that the quantum critical point is dominated by a lon

Catherine Pepin, Patrick A. Lee

In this paper we present a method to compute the exact density of states induced by $N$ non magnetic impurities in a system of two dimensional Dirac fermions in the unitarity limit. We review the case of the $π$-flux phase of the Heisenberg model and also treat the disordered d-wave superconductor. In both case we find additional states in the gap with $δρ(ω

D. Davidovic, M. Tinkham

This papaer has been withdrawn

J. Schiotz, A. E. Carlsson

We use computer simulations to study the behavior of atomically sharp and blunted cracks in various f.c.c. metals. The simulations use effective medium potentials which contain many-body interactions. We find that when using potentials representing platinum and gold a sharp crack is stable with respect to the emission of a dislocation from the crack tip, whe

Yoshiyuki Y. Yamaguchi, Yasusada Nambu

Renormalization group method is one of the most powerful tool to obtain approximate solutions to differential equations. We apply the renormalization group method to Hamiltonian systems whose integrable parts linearly depend on action variables. We show that the renormalization group method gives the same approximate solutions as canonical perturbation theor

Stanley L. Robertson

GRB 990123 may have radiated more than one solar mass equivalent in just its gamma emissions. Though this may be within the upper limit of the binding energy available from neutron stars in the Schwarzschild metric, it is difficult to imagine a process with the required efficiency of conversion to gamma rays. Neutron stars of ~10 solar mass are permitted in

Harry I. Teplitz, Ian S. McLean, Matthew A. Malkan

We present the results of an infrared survey of QSO fields at z=0.95, 0.995 and 1.5. Each z<1 field was imaged to typical continuum limits of J=20.5, Kprime=19 (5 sigma), and line fluxes of 1.3E10{-16}ergs/cm^2/s (1 sigma)in a 1% interference filter. 16 fields were chosen with z~0.95 targets, 14 with z~0.995 and 6 with z~1.5. A total area of 0.05 square degr

D. Elbaz, H. Aussel, C. J. Cesarsky, F. X. Desert

ISOCAM extragalactic mid-infrared deep surveys have detected a population of strong IR emitters ten times more numerous than expected if there were no evolution from z<0.2 (IRAS) up to the maximum redshift of these galaxies (z=1.5). The mid-IR cosmic background produced by these galaxies (2.35+/-0.8 nW m^-2 sr^-1, at 15 microns above 50 microJy) is larger th

Piero Madau

There has been remarkable progress recently in both observational and theoretical studies of galaxy formation and evolution. Largely due to a combination of deep Hubble Space Telescope imaging, Keck spectroscopy, and COBE far-IR background measurements, new constraints have emerged on the emission history of the galaxy population as a whole. While the bulk o

T. Shahbaz, P. H. Hauschildt, T. Naylor, F. Ringwald

We have obtained high resolution echelle spectroscopy of the recurrent nova T CrB. We find that the surface lithium abundance in T CrB is signifcantly enhanced compared to field M giants, where it is not detectable. We offer possible explanations for this in terms of either a delay in the onset of convection in the giant star, enhanced coronal activity due t

L. Maraschi, G. Fossati, F. Tavecchio, L. Chiappetti

Mkn 421 was observed for about two days with BeppoSAX, prior to and partly overlapping the start of a 1 week continuous exposure with ASCA in April 1998, as part of a world-wide multiwavelength campaign. A pronounced, well defined, flare observed in X-rays was also observed simultaneously at TeV energies by the Whipple Observatory&#39;s 10 m gamma-ray telesc

A. Cattaneo, M. G. Haehnelt, M. J. Rees

The growth of supermassive black holes by merging and accretion in hierarchical models of galaxy formation is studied by means of Monte Carlo simulations. A tight linear relation between masses of black holes and masses of bulges arises if if the mass accreted by supermassive black holes scales linearly with the mass forming stars and if the redshift evoluti

Pablo Reig, Paul Roche

We present RXTE observations of two recently identified massive X-ray binaries. RX J0440.9+4431/BSD 24-491 and RX J1037.5-564/LS 1698 are confirmed as accreting Be/X-ray systems following the discovery of X-ray pulsations, with barycentric pulse periods of 202.5$\pm$0.5 s and 860$\pm$2 s respectively. The X-ray spectral analysis shows that the energy spectra

John Dubinski, J. Christopher Mihos, Lars Hernquist

We present an extensive parameter survey to study the influence of halo mass profiles on the development of tidal tails in interacting disk galaxies. We model the galaxies using a fixed exponential disk with a central bulge and vary the halo potential over a range of parameters using both the Hernquist and NFW mass distributions, probing the effect of the ha

Nikita Nekrasov, Samson L. Shatashvili

We show that the $\mathcal{N}=0$ theories on the self-dual D3-branes of Type 0 string theory are in the class of the previously considered tadpole-free orbifolds of $\mathcal{N} = 4$ theory (although they have SO(6) global symmetry) and hence have vanishing beta function in the planar limit to all orders in 't Hooft coupling. Also, all planar amplitudes in t

Adan Cabello, Jose L. Cereceda

This paper has been withdrawn.

Cristopher Moore, Mats G. Nordahl, Nelson Minar, Cosma Shalizi

We study the dynamics of topological defects in the triangular Ising antiferromagnet, a related model on the square lattice equivalent to the six-vertex ice model, and the three-state antiferromagnetic Potts model on the square lattice. Since each of these models has a height representation in which defects are screw dislocations, we expect them to be attrac

Edmond L. Berger, Michael Klasen, Tim Tait

We report a next-to-leading order (NLO) calculation of the production of gaugino-like charginos ($\chargino$) and neutralinos ($\neutralino$) in association with gluinos ($\gluino$) at hadron colliders, including the strong corrections from colored particles and sparticles. We predict inclusive cross sections at the Fermilab Tevatron and CERN LHC. The NLO cr

Thomas E. Harrison, Bernard J. McNamara, Paula Szkody, Barbara J. McAurthur

We report astrometric parallaxes for three well known dwarf novae obtained using the Fine Guidance Sensors on the Hubble Space Telescope. We found a parallax for SS Aurigae of Pi = 5.00 +/- 0.64 mas, for SS Cygni we found Pi = 6.02 +/- 0.46 mas, and for U Geminorum we obtained Pi = 10.37 +/- 0.50 mas. These represent the first true trigonometric parallaxes o

Alberto S. Cattaneo, Giovanni Felder

We give a quantum field theory interpretation of Kontsevich&#39;s deformation quantization formula for Poisson manifolds. We show that it is given by the perturbative expansion of the path integral of a simple topological bosonic open string theory. Its Batalin-Vilkovisky quantization yields a superconformal field theory. The associativity of the star produc

P. Sikivie

I investigate the caustics produced by the fall of collisionless dark matter in and out of a galaxy in the limit of negligible velocity dispersion. The outer caustics are spherical shells enveloping the galaxy. The inner caustics are rings. These are located near where the particles with the most angular momentum are at their distance of closest approach to

Pablo Reig, Paul Roche

We report on the discovery of X-ray pulsations from the Be/X-ray system LS 992/RX J0812.4-3114 during an RXTE observation. From a timing analysis of the source we obtained a barycentric pulse period of 31.8851 \pm 0.0004 s. The pulse profile is highly structured and departs from a pure sinusoidal shape. It shows a sharp dip that may indicate absorption by th

F. Cano, P. Faccioli, M. Traini

Significant differences between transverse and longitudinal polarized parton distributions are found at low energies within a light-front covariant quark model of the nucleon. These differences are due to relativistic spin effects introduced by the Melosh rotations and survive evolution to higher $Q^2$ scales. A specific observable related to double-spin asy

Thomas John, Ralf Stannarius, Ulrich Behn

We report on-off intermittency in electroconvection of nematic liquid crystals driven by a dichotomous stochastic electric voltage. With increasing voltage amplitude we observe laminar phases of undistorted director state interrupted by shorter bursts of spatially regular stripes. Near a critical value of the amplitude the distribution of the duration of lam

Christophe Chatelain, Bertrand Berche

We present a numerical study of 2D random-bond Potts ferromagnets. The model is studied both below and above the critical value $Q_c=4$ which discriminates between second and first-order transitions in the pure system. Two geometries are considered, namely cylinders and square-shaped systems, and the critical behavior is investigated through conformal invari

Domenico Giulini, Donald Marolf

This work addresses certain ambiguities in the Dirac approach to constrained systems. Specifically, we investigate the space of so-called ``rigging maps&#39;&#39; associated with Refined Algebraic Quantization, a particular realization of the Dirac scheme. Our main result is to provide a condition under which the rigging map is unique, in which case we also

P. Cea, M. Consoli, L. Cosmai, P. M. Stevenson

Using a high-statistics lattice simulation of the Ising limit of $(λΦ^4)_4$ theory, we have measured the susceptibility and propagator in the broken phase. We confirm our earlier finding of a discrepancy between the field re-scaling implied by the propagator data and that implied by the susceptibility. The discrepancy becomes {\it worse} as one goes closer t

Arne Brataas, Gen Tatara, Gerrit E. W. Bauer

We study transport through ballistic and diffuse ferromagnetic domain walls in a two-band Stoner model with a rotating magnetization direction. For a ballistic domain wall, the change in the conductance due to the domain wall scattering is obtained from an adiabatic approximation valid when the length of the domain wall is much longer than the Fermi waveleng

K. Coble, M. Dragovan, J. Kovac, N. W. Halverson

Observations of the microwave sky using the Python telescope in its fifth season of operation at the Amundsen-Scott South Pole Station in Antarctica are presented. The system consists of a 0.75 m off-axis telescope instrumented with a HEMT amplifier-based radiometer having continuum sensitivity from 37-45 GHz in two frequency bands. With a 0.91 deg x 1.02 de

Ashoke Sen

We show that the tachyonic kink solution on a pair of D-p-branes in the bosonic string theory can be identified with the D-(p-1)-brane of the same theory. We also speculate on the possibility of obtaining the D-(p-1)-brane as a tachyonic lump on a single D-p-brane. We suggest a possible reinterpretation of the first result which unifies these two apparently

Freddy P. Zen, Hendry I. Elim

The integrable vector nonlinear Schrodinger (vector NLS) equation is investigated by using Zakharov-Shabat (ZS) scheme. We get a Lax pair formulation of the vector NLS model. Multi-soliton solution of the equation is also derived by using inverse scattering method of ZS scheme. We also find that there is an elastic and inelastic collision of the bright and d

Chun Wa Wong

The $d^* \to d ππ$ partial decay width has been calculated in a wave-function model for $d^*$ and $d$. It is found to be smaller than a previous estimate by a factor of 7. A previously proposed dependence on dibaryon sizes is confirmed. Additional dependence on the high-momentum components of dibaryon wave functions is found.

I. V. Volovich

Mathematical models of quantum computers such as a multidimensional quantum Turing machine and quantum circuits are described and its relations with lattice spin models are discussed. One of the main open problems one has to solve if one wants to build a quantum computer is the decoherence due to the coupling with the environment. We propose a possible solut

S. Sivakumar

We show that a class of even and odd nonlinear coherent states, defined as the eigenstates of product of a nonlinear function of the number operator and the square of the boson annihilation operator, can be generated in the center-of-mass motion of a trapped and bichromatically laser-driven ion. The nonclasscial properties of the states are studied.

Hagen Kleinert, Axel Pelster, Michael Bachmann

We introduce a general class of generating functionals for the calculation of quantum-mechanical expectation values of arbitrary functionals of fluctuating paths with fixed end points in configuration or momentum space. The generating functionals are calculated explicitly for harmonic oscillators with time-dependent frequency, and used to derive a smearing f

Jyotipratim Ray Chaudhuri, Bimalendu Deb, Gautam Gangopadhyay Deb Shankar Ray

We extend the quantum theory of dissipation in the context of system-reservoir model, where the reservoir in question is kept in a nonequilibrium condition. Based on a systematic separation of time scales involved in the dynamics, appropriate generalizations of the fluctuation-dissipation and Einstein&#39;s relations have been pointed out. We show that the W