April 1998 arXiv papers — page 8

A. Ghosh, P. Mitra

It is shown that Zaslavskii's misunderstanding of our published proof of the irrelevance of all extremal black hole configurations (whether with equal charge and mass or not) rests on his refusal to see the essential difference between the correct inequality governing extremal and non-extremal actions and his incorrect version.

Emil J. Martinec

We explore the connection between anti-deSitter supergravity and gauge theory, in the context of bound states of many D1 and D5 branes. The near-horizon $AdS_3$ supergravity describes the identity sector of the conformal field theory produced by the brane dynamics. A variant of anomaly inflow (for the 2d conformal anomaly) is involved. Dynamical matter field

H. Schmid, G. Raffelt, A. Leike

The bremsstrahlung process Nu_Tau -> Nu_e E+ E- Gamma is the dominant photon-producing decay of heavy Tau neutrinos with m_Nu_Tau > 2 m_e so that this process is instrumental for supernova 1987A constraints on the properties of these particles, notably on their mixing amplitude with Nu_e. We calculate the rate of the bremsstrahlung process as well as the pho

R. Kreckel, D. Kreimer, K. Schilcher

We describe a first attempt to calculate scalar 2-loop box-functions with arbitrary internal masses, applying a novel method proposed in hep-ph/9407234. Four of the eight integrals are accessible to integration by means of the residue theorem, leaving a rational function in the remaining variables. The result of the procedure is a three- or sometimes two-dim

D. A. Ross

We discuss the significance of the next-to-leading order term in the BFKL equation on the energy dependence of diffractive processes controlled by the perturbative QCD pomeron. It is shown that whereas the large negative corrections do indeed reduce the rate of growth of diffractive amplitudes with increasing energy, this reduction is considerably less than

S. Plaszczynski

The BABAR experiment is a new generation detector located at the SLAC B factory PEP-II ring which should start taking data at the end of 1999. Its main goal is the study of CP violation in the B0-B0b system. After explaining the nature of this CP violation, I review the scientific program for achieving this study in many different modes, in the light of the

Gi-Chol Cho

Impacts on new physics search from $\bbbar, \kkbar$ mixings and the rare decay $\kplusdecay$ are discussed. We show that, in a certain class of new physics models, the extra contributions to those processes can be parametrized by its ratio to the standard model (SM) contribution with the common CKM factors. We introduce two ratios to measure the new physics

R. Foot, R. R. Volkas, O. Yasuda

Neutrino oscillation scenarios involving large angle $ν_μ \to ν_e$ oscillations are disfavoured in the parameter range $Δm^2/eV^2 >~ 10^{-3}$ by recent results from the CHOOZ reactor-based $\barν_e$ disappearance experiment. For this reason we extend our previous work on up-down asymmetries for various oscillation scenarios by computing up-down asymmetries a

Deborah A. Harris, Kevin S. McFarland

Several different scenarios for neutrino scattering experiments using a neutrino beam from the muon collider complex are discussed. The physics reach of a neutrino experiment at the front end of a muon collider is shown to extend far beyond that of current neutrino experiments, since the high intensity neutrino beams one would see at the muon collider allow

R. Casadio, B. Harms

In this paper we continue the analysis of our previous papers and study the affect of the existence of a non-trivial dilaton background on the propagation of electromagnetic waves in the Kerr-Newman dilatonic black hole space-time. For this purpose we again employ the double expansion in both the background electric charge and the wave parameters of the rele

M. A. Grebeniuk, V. D. Ivashchuk, V. N. Melnikov

Multidimensional cosmological model with static internal spaces describing the evolution of an Einstein space of non-zero curvature and n internal spaces is considered. The action contains several dilatonic scalar fields and antisymmetric forms and lambda-term. When forms are chosen to be proportional to volume forms of p-brane submanifolds of internal space

Z. Toroczkai

We investigate the lattice walk performed by a tagged member of an infinite `sea' of particles filling a d-dimensional lattice, in the presence of a Brownian vacancy. Particle-particle exchange is forbidden; the only interaction between them being hard core exclusion. The tagged particle, differing from the others only by its tag, moves only when it exch

Klaus Kirsten, David J. Toms

We discuss the phenomenon of Bose-Einstein condensation under general external conditions using connections between partition sums and the heat-equation. Thermodynamical quantities like the critical temperature are given in terms of the heat-kernel coefficients of the associated Schrödinger equation. The general approach is applied to situations where the ga

Peter D. Olmsted, Scott T. Milner

We compute phase diagrams for $A_nB_m$ starblock copolymers in the strong-segregation regime as a function of volume fraction $ϕ$, including bicontinuous phases related to minimal surfaces (G, D, and P surfaces) as candidate structures. We present the details of a general method to compute free energies in the strong segregation limit, and demonstrate that t

Alberto Franceschetti, Lin-Wang Wang, Alex Zunger

We show that the method used by Ogut, Chelikowsky and Louie (Phys. Rev. Lett. 79, 1770 (1997)) to calculate the optical gap of Si nanocrystals omits an electron-hole polarization energy. When this contribution is taken into account, the corrected optical gap is in excellent agreement with semi-empirical pseudopotential calculations.

Ya. M. Blanter, M. Buttiker

We investigate analytically the motion of underdamped particles subject to a deterministic periodic potential and a periodic temperature. Despite the fact that an underamped particle experiences the temperature oscillation many times in its escape out of a well and in its motion along the potential, a net directed current linear in the friction constant is f

R. J. F. Leote de Carvalho, E. Trizac, J. P Hansen

The non-linear Poisson-Boltzmann equation for a circular, uniformly charged platelet, confined together with co- and counter-ions to a cylindrical cell, is solved semi-analytically by transforming it into an integral equation and solving the latter iteratively. This method proves efficient, robust, and can be readily generalized to other problems based on ce

Avinash Khare

I obtain the exact ground state of $N$-fermions in $D$-dimensions $(D \geq 2)$ in case the $N$ particles are interacting via long-ranged two-body and three-body interactions and further they are also interacting via the harmonic oscillator potential. I also obtain the $N$-fermion ground state in case the oscillator potential is replaced by an $N$-body Coulom

Sara M. Cronenwett, Tjerk H. Oosterkamp, Leo P. Kouwenhoven

We demonstrate a tunable Kondo effect realized in small quantum dots. We can switch our dot from a Kondo impurity to a non-Kondo system as the number of electrons on the dot is changed from odd to even. We show that the Kondo temperature can be tuned by means of a gate voltage as a single-particle energy state nears the Fermi energy. Measurements of the temp

Rahul Siddharthan

We examine the question of whether Bethe's ansatz reproduces all states in the periodic Heisenberg XXZ and XXX spin chains. As was known to Bethe himself, there are states for which the Bethe momenta $k_n$ diverge: these are in fact the simplest examples of ``string'' solutions. The coefficients of the Bethe wavefunction, too, diverge. When there

J. Riera, D. Poilblanc, E. Dagotto

Several experiments in the context of ladder materials have recently shown that the study of simple models of anisotropic ladders (i.e. with different couplings along legs and rungs) is important for the understanding of these compounds. In this paper Exact Diagonalization studies of the one-band Hubbard and t-J models are reported for a variety of densities

N. Gurappa, Avinash Khare, Prasanta. K. Panigrahi

We establish the exact correspondence of the Calogero-Marchioro-Wolfes model and several of its generalizations with free oscillators. This connection yields the eigenstates and leads to a proof of the quantum integrability. The usefulness of our method for finding new solvable models is then demonstrated by an example.

Peter Sollich

We solve exactly and describe in detail a simplified scalar model for the low frequency shear rheology of foams, emulsions, slurries, etc. [P. Sollich, F. Lequeux, P. Hebraud, M.E. Cates, Phys. Rev. Lett. 78, 2020 (1997)]. The model attributes similarities in the rheology of such ``soft glassy materials'' to the shared features of structural disorder

A. Soffer, M. I. Weinstein

An important class of resonance problems involves the study of perturbations of systems having embedded eigenvalues in their continuous spectrum. Problems with this mathematical structure arise in the study of many physical systems, e.g. the coupling of an atom or molecule to a photon-radiation field, and Auger states of the helium atom, as well as in spectr

Jean-Luc Thiffeault, P. J. Morrison

Reduction is a process that uses symmetry to lower the order of a Hamiltonian system. The new variables in the reduced picture are often not canonical: there are no clear variables representing positions and momenta, and the Poisson bracket obtained is not of the canonical type. Specifically, we give two examples that give rise to brackets of the noncanonica

David B. Reitzel, Puragra Guhathakurta, Andrew Gould

Deep UBRI images of a 15'x15' field in the M31 galaxy's outer spheroid obtained with the KPNO 4-m telescope, and Keck 10-m telescope+LRIS I-band images, are used to isolate candidate red giant branch stars located at R=19 kpc (projected) along the minor axis. These stars are distinguished from the more numerous distant field galaxies by isolating

M. J. Drinkwater, M. D. Gregg, R. M. Smith

In a spectroscopic survey of the Fornax cluster to Bj=17.5 using the FLAIR spectrograph on the UK Schmidt Telescope we have discovered seven new compact dwarf cluster members. These were previously thought to be giant background spirals. These new members are among the most compact, high surface brightness dwarf galaxies known with absolute magnitudes of M_B

D. E. Harris, J. A. Biretta, W. Junor

Beginning in 1995 June, we have obtained an observation of M87 with the ROSAT High Resolution Imager (HRI) every 6 months. We present the measurements of X-ray intensity for the core and knot A through 1998 January. We find significant changes in both components. For the core, intensities measured in 95 Jun, 96 Dec, and 97 Dec are roughly 30% higher than val

D. E. Harris, J. A. Biretta, W. Junor

We describe asymmetrical features in a long exposure X-ray map of M87 made with the ROSAT High Resolution Imager (HRI). A bright triangular region is marked by a linear `spur' along one edge. The structure of this spur suggests an interpretation of a tangential view of a shock front 18 kpc long. None of the brighter features are spatially coincident with

D. E. Harris

We review some of the ways that X-ray observations provide unique information on radio galaxies. Thermal bremsstrahlung X-ray emission provides detailed data on ambient densities and temperatures. These parameters in turn can be used for pressure balance calculations and can demonstrate how the ambient gas affects radio source structure. Additionally, many s

D. E. Harris, K. M. Leighly, J. P. Leahy

By summing a large number of ROSAT High Resolution Imager (HRI) observations of the variable radio galaxy 3C 390.3, we demonstrate that the X-ray emission associated with the northern radio lobe (reported by Prieto 1997) can be identified with hotspot B. None of the other hotspots have been detected. We present evidence that the anomalous X-ray emission is t

J. D. Silverman, D. E. Harris, W. Junor

26W20, a radio galaxy located at a projected distance of 2.2 Mpc from the center of Abell 754 (z=0.054) exhibits core emission properties similar to those of a BL Lac object. New radio observations and VLA archival data show parsec scale features in the core (L_{r} approx.10^{41}) ergs/s with a flat spectrum. From observations with ROSAT, we demonstrate that

F. W. Stecker, O. C. De Jager

We present a new calculation of the intergalactic gamma-ray absorption coefficient as a function of both energy and redshift. In reexamining this problem, we make use of a new, empirically based calculation (as opposed to previous model calculations) of the intergalactic infrared radiation field. We find smaller opacities than those given previously (Stecker

R. P. van der Marel, F. C. van den Bosch

We present an HST study of the nuclear region of the E4 radio galaxy NGC 7052, which has a nuclear disk of dust and gas. The WFPC2 was used to obtain B, V and I broad-band images and an H_alpha+[NII] narrow-band image. The FOS was used to obtain H_alpha+[NII] spectra along the major axis, using a 0.26 arcsec diameter circular aperture. The observed rotation

Przemyslaw Wozniak, Michal Szymanski

We search OGLE-I photometric database for stars, which, as defined by formal criteria adopted by OGLE-I microlensing search, showed variability during only one out of 3 or 4 observing seasons. The results include 17 previously reported microlensing events, 2 newly discovered candidate events and 15 intrinsically variable stars that have a potential of contam

C. M. Rudge, D. J. Raine

The nuclei of a wide class of active galaxies emit broad emission lines with widths at half maximum (FWHM) in the range $10^{3}-10^{4}$ km s$^{-1}$. This spread of widths is not solely a consequence of the range of the luminosities of these sources since a plot of width versus luminosity shows a large scatter. We propose that the broad line emission region (

T. J. Galama, R. A. M. J. Wijers, M. Bremer, P. J. Groot

We have reconstructed the spectrum of the afterglow of GRB 970508, on May 21.0 UT (12.1 days after the GRB), on the basis of observations spanning the X-ray to radio range. The low-frequency power law index of the spectrum, $α=0.44\pm0.07$ ($F_ν\proptoν^α$), is in agreement with the expected value $α=1/3$ for optically thin synchrotron radiation. The 1.4 GHz

T. J. Galama, R. A. M. J. Wijers, M. Bremer, P. J. Groot

We report on Westerbork 1.4 GHz radio observations of the radio counterpart to $γ$-ray burst GRB~970508, between 0.80 and 138 days after this event. The 1.4 GHz light curve shows a transition from optically thick to thin emission between 39 and 54 days after the event. We derive the slope $p$ of the spectrum of injected electrons ($dN/dγ_{e}\proptoγ_{e}^{-p}

Ch. Schaab, F. Weber, M. K. Weigel

The possibility of a neutron m=2-superfluid in the interior of neutron stars is investigated. This pairing state is energetically favoured in strong magnetic fields ($H\sim 10^{16}-10^{17}$ G). Because of the node in the angular-dependent energy gap along the field direction the neutrino emissivity is only suppressed polynomially as function in $T/T_{c}$ ins

M. Girardi, G. Giuricin, F. Mardirossian, M. Mezzetti

We evaluate in a homogeneous way the optical masses of 170 nearby clusters (z< 0.15). The sample includes both data from the literature and the new ENACS data (Katgert et al. 1996, 1998). On the assumption that mass follows the galaxy distribution, we compute the masses of each cluster by applying the virial theorem to the member galaxies. We constrain the m

G. L. Israel, S. Campana, G. Cusumano, F. Frontera

We analysed 13 archival ROSAT PSPC and HRI observations which included the position of a newly discovered 59s X-ray pulsar in the Small Magellanic Cloud, 1SAX J0054.9-7226 = 2E 0053.2-7242. The source was detected three times between 1991 and 1996 at a luminosity level ranging from about 8 x 10^{34} - 4 x 10^{35} erg s^{-1} (0.1-2.4 keV). Highly significant

Max Tegmark, Daniel J. Eisenstein, Wayne Hu

We compute the accuracy with which Omega and Lambda can be measured by combining future SN Ia and CMB experiments, deriving a handy expression for the SN Ia Fisher information matrix. The two data sets are found to be highly complementary: a joint analysis reduces the error bars by more than an order of magnitude compared to a separate analysis of either dat

E. D&#39;Hoker, D. H. Phong

The Seiberg-Witten curves and differentials for $\N=2$ supersymmetric Yang-Mills theories with one hypermultiplet of mass $m$ in the adjoint representation of the gauge algebra $\G$, are constructed for arbitrary classical or exceptional $\G$ (except $G_2$). The curves are obtained from the recently established Lax pairs with spectral parameter for the (twis

E. D&#39;Hoker, D. H. Phong

The elliptic Calogero-Moser Hamiltonian and Lax pair associated with a general simple Lie algebra $\G$ are shown to scale to the (affine) Toda Hamiltonian and Lax pair. The limit consists in taking the elliptic modulus $τ$ and the Calogero-Moser couplings $m$ to infinity, while keeping fixed the combination $M = m e^{i πδτ}$ for some exponent $δ$. Critical s

E. D&#39;Hoker, D. H. Phong

We construct a Lax pair with spectral parameter for the elliptic Calogero-Moser Hamiltonian systems associated with each of the finite dimensional Lie algebras, of the classical and of the exceptional type. When the spectral parameter equals one of the three half periods of the elliptic curve, our result for the classical Lie algebras reduces to one of the L

Masamichi Nishino, Kizashi Yamaguchi, Seiji Miyashita

By studying the dynamics of the metastable magnetization of a statistical mechanical model we propose a switching mechanism of photoinduced magnetization. The equilibrium and nonequilibrium properties of the Blume-Capel (BC) model, which is a typical model exhibiting metastability, are studied by mean field theory and Monte Carlo simulation. We demonstrate r

D. M. Appleby

The distribution of measured values for maximally accurate, unbiased simultaneous measurements of position and momentum is investigated. It is shown, that if the measurement is retrodictively optimal, then the distribution of results is given by the initial state Husimi function (or Q-representation). If the measurement is predictively optimal, then the dist

D. M. Appleby

The problem of characterising the accuracy of, and disturbance caused by a joint measurement of position and momentum is investigated. In a previous paper the problem was discussed in the context of the unbiased measurements considered by Arthurs and Kelly. It is now shown, that suitably modified versions of these results hold for a much larger class of simu

Krystyna Kuperberg

For every triple of integers a, b, and c, such that a>O, b>0, and c>1, there is a homogeneous, non-bihomogeneous continuum whose every point has a neighborhood homeomorphic the Cartesian product of three Menger compacta m^a, m^b, and m^c. In particular, there is a homogeneous, non-bihomogeneous, Peano continuum of covering dimension four.

A. M. Bratkovsky, J. H. Nickel

We have studied tunnel magnetoresistance (TMR) in junctions with 3d ferromagnetic electrodes. Previously we predicted that defects in the barrier would result in reduced effective polarization P of the impurity assisted current. This is confirmed experimentally in the present work: introductions of defects into the barrier drastically decreases the TMR. The

Dan T. Fuchs, Eli Zeldov, Tsuyoshi Tamegai, Shuuichi Ooi

The vortex matter phase diagram of BSCCO crystals is analyzed by investigating vortex penetration through the surface barrier in the presence of a transport current. The strength of the effective surface barrier, its nonlinearity, and asymmetry are used to identify a possible new ordered phase above the first-order transition. This technique also allows sens

Richard Berkovits, Yshai Avishai

The local persistent current in two dimensional strongly interacting systems is investigated. As the interaction strength is enhanced the current in the sample undergoes a transition from diffusive to ordered flow. The strong interacting flow has the characteristics of a plastic flow through dislocations in the pinned charge density wave which develops in th

Chih-Lung Chou

We discuss a supersymmetric grand unified model which has gauge group SU(5) $\times$ SU(5) $\times$ SU(5), with matter fields transforming asymmetrically under different gauge SU(5) groups. We observe that the gauge structure of the model leads to approximate texture zero structures in fermion mass matrices and a natural hierarchy in the Yukawa couplings. Th

Yoshiyuki Y. Yamaguchi, Yasusada Nambu

We investigate Hamiltonian systems with two degrees of freedom by using renormalization group method. We show that the original Hamiltonian systems and the renormalization group equations are integrable if the renormalization group equations are Hamiltonian systems up to the second leading order of a small parameter.

Steven B. Giddings, Feike Hacquebord, Herman Verlinde

In this paper we use the matrix string approach to begin a study of high energy scattering processes in M-theory. In particular we exhibit an instanton-type configuration in 1+1 super-Yang-Mills theory that can be interpreted as a non-perturbative description of a string interaction. This solution is used to describe high energy processes with non-zero longi

Jun&#39;ichi Yokoyama

The mass function of primordial black holes created through the near-critical gravitational collapse is calculated in a manner fairly independent of the statistical distribution of underlying density fluctuation, assuming that it has a sharp peak on a specific scale. Comparing it with various cosmological constraints on their mass spectrum, some newly exclud

Andris Ambainis, Ashwin Nayak, Amnon Ta-Shma, Umesh Vazirani

We consider the possibility of encoding m classical bits into much fewer n quantum bits so that an arbitrary bit from the original m bits can be recovered with a good probability, and we show that non-trivial quantum encodings exist that have no classical counterparts. On the other hand, we show that quantum encodings cannot be much more succint as compared

B. J. Suh, Y. Yoshinari, J. D. Thompson, P. C. Hammel

^{139}La nuclear quadrupole resonance measurements in lightly doped La_2Cu_{1-x}Li_xO_4 have been performed to reveal the dependence of the magnetic properties of the antiferromagnetic CuO_2 planes on the character of the doped holes and their interactions with the dopant. A detailed study shows that the magnetic properties are remarkably insensitive to the

D. V. Juriev

The paper is devoted to the symmetry aspects of 2D nonlocal field theory, which is the simplest deformation of the conformally invariant quantum field theory with one free bosonic field. The inverse problem of representation theory is solved for $q_R$-conformal symmetries, which are infinite dimensional hidden symmetries of the field theory. There is develop

H. van Hecke, H. Sorge, N. Xu

Recently reported transverse momentum distributions of strange hadrons produced in Pb(158AGeV) on Pb collisions and corresponding results from the relativistic quantum molecular dynamics (RQMD) approach are examined. We argue that the experimental observations favor a scenario in which multi-strange hadrons are formed and decouple from the system rather earl

Alexei Borodin, Grigori Olshanski

In Part I (G.Olshanski, math.RT/9804086) and Part II (A.Borodin, math.RT/9804087) we developed an approach to certain probability distributions on the Thoma simplex. The latter has infinite dimension and is a kind of dual object for the infinite symmetric group. Our approach is based on studying the correlation functions of certain related point stochastic p

Alexei Borodin

We continue the study of the correlation functions for the point stochastic processes introduced in Part I (G.Olshanski, math.RT/9804086). We find an integral representation of all the correlation functions and their explicit expression in terms of multivariate hypergeometric functions. Then we define a modification (``lifting&#39;&#39;) of the processes whi

Grigori Olshanski

We study a 2-parametric family of probability measures on an infinite-dimensional simplex (the Thoma simplex). These measures originate in harmonic analysis on the infinite symmetric group (S.Kerov, G.Olshanski and A.Vershik, Comptes Rendus Acad. Sci. Paris I 316 (1993), 773-778). Our approach is to interpret them as probability distributions on a space of p

Romesh K. Kaul

Chern-Simons theories, which are topological quantum field theories, provide a field theoretic framework for the study of knots and links in three dimensions. These are rare examples of quantum field theories which can be exactly and explicitly solved. Expectation values of Wilson link operators yield a class of link invariants, the simplest of them is the f

Hai-Yang Cheng, Chi-Yee Cheung, Wei-Min Zhang

In this paper we present a detailed formulation for a recently proposed effective field theory to describe the nonperturbative QCD dynamics of heavy mesons. This effective theory incorporates with heavy quark symmetry (HQS) and the heavy quark effective theory (HQET). Heavy mesons in this theory are constructed as composite particles of a heavy quark bounded

H. Suganuma, F. Araki, M. Fukushima, H. Ichie

We study the nonperturbative QCD in terms of topological objects, i.e., QCD-monopoles and instantons. In the &#39;t Hooft abelian gauge, QCD is reduced into an abelian gauge theory with QCD-monopoles, and the confinement mechanism can be understood with the dual superconductor picture. Regarding the flux-tube ring as the glueball, we study the glueball prope

Nikolai Uraltsev

I give an introduction to the QCD-based theory of the heavy flavor hadrons and their weak decays. Trying to remain at the next-to-elementary level and skip technicalities, I concentrate on the qualitative description of the most important applications and physical meaning of the theoretical statements. The numerical results of the dedicated theoretical analy

H. Suganuma, K. Amemiya, A. Tanaka, H. Ichie

Based on the dual-superconductor picture, we study the confinement physics in QCD in terms of the monopole in the maximally abelian (MA) gauge using the SU(2) lattice QCD. In the MA gauge, the off-diagonal gluon component is forced to be small, and hence microscopic abelian dominance on the link variable is observed in the lattice QCD for the whole region of

Malte Henkel, Stéphane Andrieu, Philippe Bauer, Michel Piecuch

The critical temperature of thin Fe layers on Ir(100) is measured through Mößbauer spectroscopy as a function of the layer thickness. From a phenomenological finite-size scaling analysis, we find an effective shift exponent lambda = 3.15 +/- 0.15, which is twice as large as the value expected from the conventional finite-size scaling prediction lambda=1/nu,

Scott J. Kenyon, Jane X. Luu

We describe planetesimal accretion calculations in the Kuiper Belt. Our evolution code simulates planetesimal growth in a single annulus and includes velocity evolution but not fragmentation. Test results match analytic solutions and duplicate previous simulations at 1 AU. In the Kuiper Belt, simulations without velocity evolution produce a single runaway bo

Scott J. Kenyon, David I. Brown, Chris Tout, Perry Berlind

This paper describes the first optical spectroscopic survey of class I sources (also known as embedded sources and protostars) in the Taurus-Auriga dark cloud. We detect 10 of the 24 known class I sources in the cloud at 5500-9000 A. All detected class I sources have strong H-alpha emission; most also have strong [O I] and [S II] emission. These data - toget

T. A. A. Sigut, Anil K. Pradhan

We have calculated FeII emission line strengths for Active Galactic Nuclei Broad-Line Regions using precise radiative transfer and Iron Project atomic data. We improve the treatment of all previously considered excitation mechanisms for the FeII emission, continuum fluorescence, collisional excitation, fluorescence by self-overlap among the iron lines, and f

Kenji Bekki

We numerically investigate chemodynamical evolution of interstellar medium (ISM) in gas-rich disk-disk galaxy mergers in order to explore the origin of fundamental chemical properties of halo ISM observed in elliptical galaxies. Main results obtained in this chemodynamical study are the following three. (1) Elliptical galaxies formed by gas-rich mergers show

V. Borkous, A. S. Kaniovsky, R. A. Sunyaev, V. V. Efremov

We present the results of the observations of the giant bursts from the X-ray pu lsar A0535+26 made by HEXE onboard Mir-Kvant in April 1989, November 1993 and February 1994. The pulse periods were measured, pulse profiles in different energy bands were produced, and their variability was investigated. The power density spectra (PDS) in 2x10^(-3)-1 Hz range i

J. M. Niczyporuk, E. E. W. Bruins

We describe a general approach to quark flavor tagging in polarized hadronic processes, with particular emphasis on semi-inclusive deep inelastic scattering. A formalism is introduced that allows one to relate chosen quark flavor polarizations to an arbitrary combination of final-state hadron spin asymmetries. Within the context of the presented formalism, w

John Ellison, Jose Wudka

We review studies of the trilinear gauge boson couplings at the Tevatron proton-antiproton collider from data collected by the CDF and D0 collaborations during the period 1992--1996. The gauge boson couplings are a fundamental prediction of the standard model, resulting from the non-Abelian nature of the theory. Therefore, experimental tests of the couplings

Daniela Bigatti

We aim to connect the non commutative geometry ``quotient space&#39;&#39; viewpoint with the standard super Yang Mills theory approach in the spirit of Connes-Douglas-Schwartz and Douglas-Hull description of application of noncommutative geometry to matrix theory. This will result in a relation between the parameters of a rational foliation of the torus and

Kazusumi Ino

We investigate the modular properties of the characters which appear in the partition functions of nonabelian fractional quantum Hall states. We first give the annulus partition function for nonabelian FQH states formed by spinon and holon (spinon-holon state). The degrees of freedom of spin are described by the affine SU(2) Kac-Moody algebra at level $k$. T

A. I. L&#39;vov

Recently, a longitudinal sum rule for the electric polarizability of nuclei was used to revise a relativistic correction in a dipole sum rule for the polarizability (nucl-th/9802011). This revision is shown to be wrong because of neglecting an asymptotic contribution in the underlying dispersion relation. The status and correct use of the longitudinal sum ru

Andrew R Liddle, Anupam Mazumdar, Franz E Schunck

In inflationary scenarios with more than one scalar field, inflation may proceed even if each of the individual fields has a potential too steep for that field to sustain inflation on its own. We show that scalar fields with exponential potentials evolve so as to act cooperatively to assist inflation, by finding solutions in which the energy densities of the

C. de Calan, A. P. C. Malbouisson, F. S. Nogueira, N. F. Svaiter

We consider a Ginzburg-Landau model for superconductivity with a Chern-Simons term added. The flow diagram contains two charged fixed points corresponding to the tricritical and infrared stable fixed points. The topological coupling controls the fixed point structure and eventually the region of first order transitions disappears. We compute the critical exp

C. D. Dermer, J. Chiang, M. Boettcher

A simple function for the spectral power $P(ε,t) \equiv νL(ν) $ is proposed to model, with 9 parameters, the spectral and temporal evolution of the observed nonthermal synchrotron power flux from GRBs in the blast wave model. Here $ε= hν/$m$_e$c$^2$ is the observed dimensionless photon energy and $t$ is the observing time. Assumptions and an issue of lack of

R. Aldrovandi, V. C. de Andrade, J. G. Pereira

The quadratic form of the Dirac equation in a Riemann spacetime yields a gravitational gyromagnetic ratio κ_S = 2 for the interaction of a Dirac spinor with curvature. A gravitational gyromagnetic ratio κ_S = 1 is also found for the interaction of a vector field with curvature. It is shown that the Dirac equation in a curved background can be obtained as the

F. Onufrieva, P. Pfeuty, M. Kiselev

We have discovered a new nontrivial aspect of electronic topological transition (ETT) in a 2D free fermion system on a square lattice. The corresponding exotic quantum critical point, δ=δ_c, T=0, (n=1-δis an electron concentration) is at the origin of anomalous behaviour in the interacting system on one side of ETT, δ<δ_c. The most important is an appearance

M. Ulmke, P. J. H. Denteneer, V. Janis, R. T. Scalettar

We study the influence of disorder and randomly distributed impurities on the properties of correlated antiferromagnets. To this end the Hubbard model with (i) random potentials, (ii) random hopping elements, and (iii) randomly distributed values of interaction is treated using quantum Monte Carlo and dynamical mean-field theory. In cases (i) and (iii) weak

Ruth Durrer, Francesco Sylos Labini

In this letter we present an idea which reconciles a homogeneous and isotropic Friedmann universe with a fractal distribution of galaxies. We use two observational facts: The flat rotation curves of galaxies and the (still debated) fractal distribution of galaxies with fractal dimension D=2. Our idea can also be interpreted as a redefinition of the notion of

F. Csikor, Z. Fodor, J. Heitger

We present a calculation of the O(g^2,λ) perturbative corrections to the coupling anisotropies of the SU(2)-Higgs model on lattices with asymmetric lattice spacings. These corrections are obtained by a one-loop calculation requiring the rotational invariance of the gauge and Higgs boson propagators in the continuum limit. The coupling anisotropies are also d

Yasufumi Yamashita, Naokazu Shibata, Kazuo Ueda

Effect of quantum fluctuations concerned with the orbital degrees of freedom is discussed for the model with SU(4) symmetry in one dimension. An effective Hamiltonian is derived from the orbitally degenerate Hubbard model at quarter filling. This model is equivalent to the Bethe soluble SU(4) exchange model. Quantum numbers of the ground state and the lowest

M. Passera, A. Sirlin

We discuss radiative corrections to W and quark propagators in the resonance region, |s-M^2| \lsim M*Gamma. We show that conventional mass renormalization, when applied to photonic or gluonic corrections, leads in next to leading order (NLO) to contributions proportional to [M*Gamma/(s-M^2)]^n, (n=1,2...), i.e. to a non-convergent series in the resonance reg

D. Matrasulov

Schrödinger equation for two center Coulomb plus harmonic oscillator potential is solved by the method of ethalon equation at large intercenter separations. Asymptotical expansions for energy term and wave function are obtained in the analytical form.

G. Garcia-Calderon, J. L. Mateos, M. Moshinsky

In our paper [Phys. Rev. Lett. 74, 337 (1995)], we derived an exact expression for the survival and nonescape probabilities as an expansion in terms of resonant states. It was shown that these quantities exhibit at long times a different behavior. Although both decay as a power law, they have different exponents. In this paper we show that, contrary to the c

Martin J. Savage

Recent progress in using effective field theory to describe systems with two nucleons is discussed with particular emphasis placed on the inclusion of pions. Inconsistencies arising in Weinberg&#39;s power counting are demonstrated with two concrete examples. A consistent power-counting scheme is discussed in which pion exchange is sub-leading to local four-

J. C. Perez Bueno

It is shown that the family of deformed algebras ${\cal U}_λ(iso_{ω_2... ω_N}(N))$ has a different bicrossproduct structure for each $ω_a=0$ in analogy to the undeformed case.

Tamas Hausel

In this paper we consider a canonical compactification of Hitchin&#39;s moduli space of stable Higgs bundles with fixed determinant of odd degree over a Riemann surface, producing a projective variety by gluing in a divisor at infinity. We give a detailed study of the compactified space, the divisor at infinity and the moduli space itself. In doing so we rep

H. W. Braden, J. G. B. Byatt-Smith

We solve the functional equations $$ \begin{vmatrix} 1 & 1 & 1 f(x) & f(y) & f(z) f\sp{\prime}(x)& f\sp{\prime}(y)& f\sp{\prime}(z) \end{vmatrix} =0,\quad\quad \begin{vmatrix} 1 & 1 & 1 f(x) & g(y) & h(z) \\ f\sp{\prime}(x)& g\sp{\prime}(y)& h\sp{\prime}(z) \end{vmatrix} =0, for suitable functions $f$, $g$ and $h$ subject to $x+y+z=0$. These equations essent

Guido Cognola, Ilya L. Shapiro

We consider the GUT-like model with two scalar fields which has infinitesimal deviation from the conformal invariant fixed point at high energy region. In this case the dominating quantum effect is the conformal trace anomaly and the interaction between the anomaly-generated propagating conformal factor of the metric and the usual dimensional scalar field. T

Emilio Elizalde, Guido Cognola, Sergio Zerbini

In the framework leading to the multiplicative anomaly formula ---which is here proven to be valid even in cases of known spectrum but non-compact manifold (very important in Physics)--- zeta-function regularisation techniques are shown to be extremely efficient. Dirac like operators and harmonic oscillators are investigated in detail, in any number of space

B. B. Deo, L. P. Singh

We show the existence of quasi-supersymmetry as formulated by Nambu in the top-sector of the standard model. We present the explicit form of the quasi-supersymmetric charge. We also deduce,like Nambu, a quasi supersymmetric mass relation which is the same as suggested by Veltman.

D. S. Berman

We examine the D-3 brane from the point of view of the double dimensionally reduced M theory 5 brane on a torus. M-theory, IIB identifications are explicitly constructed and a possible reformulation of the D-3 brane is discussed. The duality transformation of the reduced 3-brane necessary to make the identification is discussed in detail.

H. Baer, F. E. Paige, S. D. Protopopescu, X. Tata

ISAJET is a Monte Carlo event generator for $pp$, $\bar pp$, and $e^+e^-$ interactions at high energies. This document summarizes the physics underlying the program and describes how to use it.