December 1996 arXiv papers — page 14

S. Andreon, E. Davoust, T. Heim

We have performed an isophotal analysis of galaxies in the distant (z=0.4) cluster Cl0939+4713 (Abell 851), using post-refurbished Hubble Space Telescope images. Morphological type estimates for the galaxies are given. A rigorous comparison of the properties of the types shows that early-type galaxies in Cl0939+4713 are, within the present statistical or sys

N. Bissantz, P. Englmaier, J. Binney, O. Gerhard

We examine the left-right asymmetry in the cleaned COBE/DIRBE near-infrared data of the inner Galaxy and show (i) that the Galactic bar is probably not seen very nearly end-on, and (ii) that even if it is, it is not highly elongated. The assumption of constant mass-to-light ratio is used to derive simulated terminal-velocity plots for the ISM from our model

Rodrigo Ibata, Rosemary Wyse, Gerard Gilmore, Michael Irwin

The Sagittarius galaxy (Sgr), the closest satellite galaxy of the Milky Way, has survived for many orbits about the Galaxy. Extant numerical calculations modeled this galaxy as a system with a centrally-concentrated mass profile, following the light, and found that it should lose more than one-half of its mass every 2--4 orbits and be completely disrupted lo

Jinwu Ye

Using Abelian Bosonization, we develop a simple and powerful method to calculate the correlation functions of the two channel Kondo model and its variants. The method can also be used to identify all the possible boundary fixed points and their maximum symmetry, to calculate straightforwardly the finite size spectra, to demonstrate the physical picture at th

Steven B. Giddings

A novel probe of D-brane dynamics is via scattering of a high energy ripple traveling along an attached string. The inelastic processes in which the D-brane is excited through emission of an additional attached string is considered. Corresponding amplitudes can be found by factorizing a one-loop amplitude derived in this paper. This one-loop amplitude is sho

Zurab Berezhiani, Zurab Tavartkiladze

The anomalous gauge $U(1)_A$ symmetry which could emerge in the context of the string theories can be very useful ingredient towards builting the complete supersymmetric SO(10) model. We present an example of the $SO(10)\times U(1)_A$ model which provides the ``all order'' solution to the doublet-triplet splitting problem via the missing VEV mechanis

Jussi Kalkkinen

We study a class of noncommutative geometries that give rise to dimensionally reduced Yang-Mills theories. The emerging geometries describe sets of copies of an even dimensional manifold. Similarities to the D-branes in string theory are discussed.

Dragana Popović, S. Washburn

We study conductance fluctuations in a two-dimensional electron gas as a function of chemical potential (or gate voltage) from the strongly insulating to the metallic regime. Power spectra of the fluctuations decay with two distinct exponents (1/v_l and 1/v_h). For conductivity $σ\sim 0.1 e^{2}/h$, we find a third exponent (1/v_i) in the shortest samples, an

S. Dawson

Introductory lectures on the phenomenology of the minimal supersymmetric Standard Model. The emphasis is on general signatures for supersymmetry and on the motivation for constructing supersymmetric models. These lectures are intended for experimental graduate students.

J. Kisker, H. Rieger

We study the Villain representation of the two-dimensional disordered boson Hubbard model via Monte Carlo simulations. It is shown that the probability distribution of the local susceptibility has a 1/χ^2-tail in the Bose glass phase. This gives rise to a divergence although particles are completely localized here as we prove with the help of the participati

Corinne Cerf

In this paper, we show how to split the writhe of reduced projections of oriented alternating links into two parts, called nullification writhe, or wx, and remaining writhe, or wy, such that the sum of these quantities equals the writhe w, and each quantity remains an invariant of isotopy. The chirality of oriented alternating links can be detected by a non-

M. Kirchbach, H. -J. Weber

The decoupling of the eta meson from the nucleon, as recently deduced from analyzing \bar p p collisions and eta photoproduction off the proton at threshold, is shown to provide an argument against the octet Goldstone boson nature of the eta meson. This argument concerns the structure of the strong isoscalar axial vector current. A vanishing eta-N coupling m

Andreas Albrecht

I argue that the proposition that primordial perturbations were produced by inflation is most definitely falsifyable. Far from ``predicting anything you want'', the Gaussianity and passivity of inflationary perturbations strongly constrain the possible outcomes. For example, the next generation of CMB satellites could easily prove that the perturbati

Henrik Nordborg, Gianni Blatter

The vortex system in a high-T_c superconductor has been studied numerically using the mapping to 2D bosons and the path-integral Monte Carlo method. We find a single first-order transition from an Abrikosov lattice to an entangled vortex liquid. The transition is characterized by an entropy jump dS = 0.4 k_B per vortex and layer (parameters for YBCO) and a L

S. Schwegmann, A. P. Seitsonen, H. Dietrich, H. Bludau

The local adsorption geometries of the (2x2)-N and the (sqrt(3)x sqrt(3))R30^o -N phases on the Ru(0001) surface are determined by analyzing low-energy electron diffraction (LEED) intensity data. For both phases, nitrogen occupies the threefold hcp site. The nitrogen sinks deeply into the top Ru layer resulting in a N-Ru interlayer distance of 1.05 AA and 1.

S. Falkenberg, S. D. Odintsov

We study the gauge dependence of the effective average action Gamma_k and Newtonian gravitational constant using the RG equation for Gamma_k. Then we truncate the space of action functionals to get a solution of this equation. We solve the truncated evolution equation for the Einstein gravity in the De Sitter background for a general gauge parameter alpha an

Adriano Barenco

Recent theoretical results confirm that quantum theory provides the possibility of new ways of performing efficient calculations. The most striking example is the factoring problem. It has recently been shown that computers that exploit quantum features could factor large composite integers. This task is believed to be out of reach of classical computers as

Jerzy Lukierski, Peter C. Stichel, Wojtek J. Zakrzewski

We consider a new D=2 nonrelativistic classical mechanics model providing via the Noether theorem the (2+1)-Galilean symmetry algebra with two central charges: mass m and the coupling constant k of a Chern-Simons-like term. In this way we provide the dynamical interpretation of the second central charge of the (2+1)-dimensional Galilean algebra. We discuss a

Rochus Klesse, Marcus Metzler

The spectral properties of a disordered electronic system at the metal-insulator transition point are investigated numerically. A recently derived relation between the anomalous diffusion exponent $η$ and the spectral compressibility $χ$ at the mobility edge, $χ=η/2d$, is confirmed for the integer quantum Hall delocalization transition. Our calculations are

M. K. Banerjee, J. A. Tjon

Due to the internal structure of the nucleon, we should expect, in general, that the effective meson nucleon parameters may change in nuclear medium. We study such changes by using a chiral confining model of the nucleon. We use density-dependent masses for all mesons except the pion. Within a Dirac-Brueckner analysis, based on the relativistic covariant str

A. A. Nersesyan, A. M. Tsvelik

It is shown that a sufficiently strong four-spin interaction in the spin-1/2 spin ladder can cause dimerization. Such interaction can be generated either by phonons or (in the doped state) by the conventional Coulomb repulsion between the holes. The dimerized phases are thermodynamically undistinguishable from the Haldane phase, but have dramatically differe

Michiyasu Nagasawa, Jun'ichi Yokoyama

The Jeans scale is estimated during the coexistence epoch of quark-gluon and hadron phases in the first-order QCD phase transition. It is shown that, contrary to the previous claims, reduction of the sound speed is so little that the phase transition does not affect evolution of cosmological density fluctuations appreciably.

A. Chamblin, J. M. A. Ashbourn-Chamblin

We examine the pair creation of black holes in the presence of supergravity domain walls with broken and unbroken supersymmetry. We show that black holes will be nucleated in the presence of non- extreme, repulsive walls which break the supersymmetry, but that as one allows the parameter measuring deviation from extremality to approach zero the rate of creat

Hai-Yang Cheng

Cabibbo-allowed two-body hadronic weak decays of bottom baryons are analyzed. Contrary to the charmed baryon sector, many channels of bottom baryon decays proceed only through the external or internal W-emission diagrams. Moreover, W-exchange is likely to be suppressed in the bottom baryon sector. Consequently, the factorization approach suffices to describe

Eric M. Rains

In a recent paper ([quant-ph/9610040]), Shor and Laflamme define two ``weight enumerators'' for quantum error correcting codes, connected by a MacWilliams transform, and use them to give a linear-programming bound for quantum codes. We introduce two new enumerators which, while much less powerful at producing bounds, are useful tools nonetheless. The

S. N. Molotkov, S. S. Nazin

A new cryptosystem based on the fundamental time--energy uncertainty relation is proposed. Such a cryptosystem can be implemented with both correlated photon pairs and single photon states.

S. N. Molotkov

The effects of dispersion in the communication channel on the secrecy of a quantum cryptosystem based on single photon states with different frequencies are studied. A maximum communication channel length which can still ensure the secrecy of the key generation procedure is found.

M. Dakna, T. Anhut, T. Opartny, L. Knoll

A scheme for generating Schrödinger cat-like states of a single-mode optical field by means of conditional measurement is proposed. Feeding into a beam splitter a squeezed vacuum and counting the photons in one of the output channels, the conditional states in the other output channel exhibit a number of properties that are very similar to those of superposi

Karl Svozil

A straightforward argument shows that, by allowing counterfactual elements of physical reality, any arbitrary discrete finite-dimensional operator corresponds to an observable.

Andrei Ludu, Walter Greiner

We introduce a smooth mapping of some discrete space-time symmetries into quasi-continuous ones. Such transformations are related with q-deformations of the dilations of the Euclidean space and with the non-commutative space. We work out two examples of Hamiltonian invariance under such symmetries. The Schrodinger equation for a free particle is investigated

G. A. Kotel'nikov

A new relativistic invariant version of nonlinear Maxwell equations is offerred. Some properties of these equations are considered.

A. Bulgac, G. Do Dang, D. Kusnezov

The microscopic origin of dissipation of a driven quantum many body system is addressed in the framework of a parametric banded random matrix approach. We find noticeable violations of the fluctuation-dissipation theorem and we observe also that the energy diffusion has a markedly non-Gaussian character. Within the Feynman-Vernon path integral formalism and

Bernard Pire

We review the theory of hard exclusive scattering in Quantum Chromodynamics. After recalling the classical counting rules which describe the leading scale dependence of form factors and exclusive cross-sections at fixed angle, the pedagogical example of the pion form factor is developped in some detail in order to show explicitely what factorization means in

E. Friedman, A. Gal, J. Mares

Self consistency in the analysis of transmission measurements for K^+ on several nuclei in the momentum range of 500-700 MeV/c is achieved with a "t_{eff}(rho)rho" potential and new results are derived for total cross sections. The imaginary part of the t_{eff} amplitude is found to increase linearly with the average nuclear density in excess of a th

Andrei Ludu, Aurel Sandulescu, Walter Greiner

By introducing in the hydrodynamic model, i.e. in the hydrodynamic equations and the corresponding boundary conditions, the higher order terms in the deviation of the shape, we obtain in the second order the Korteweg de Vries equation (KdV). The same equation is obtained by introducing in the liquid drop model (LDM), i.e. in the kinetic, surface and Coulomb

Abhee K. Dutt-Mazumder, Jan-e Alam, Binayak Dutta-Roy, Bikash Sinha

The excess of low invariant mass dilepton yield in heavy ion collisions arising from reduction in the rho meson mass at finite temperatures is partially suppressed because of the effect on the width of the rho meson induced by Bose enhancement, essentially due to emission of pions in a medium of the pion gas in the central rapidity region. The sensitivity of

Marvin Justice

A feedforward multilayered neural network has been trained to "recognize" true V0's in the presence of a large combinatoric background using simulated data for 2 GeV/nucleon Ni + Cu interactions. The resulting neural network filter has been applied to actual data from the EOS TPC experiment. An enhancement of signal to background over more tradit

P. Di Francesco

We prove a determinantal formula for quantities related to the problem of enumeration of (semi-) meanders, namely the topologically inequivalent planar configurations of non-self-intersecting loops crossing a given (half-) line through a given number of points. This is done by the explicit Gram-Schmidt orthogonalization of certain bases of subspaces of the T

L. Griguolo, D. Seminara

We investigate the quantum effects of the non-minimal matter-gravity couplings derived by Cangemi and Jackiw in the realm of a specific fermionic theory, namely the abelian Thirring model on a Riemann surface of genus zero and one. The structure and the strength of the new interactions are seen to be highly constrained, when the topology of the underlying ma

Jens Hoppe

It is shown that time-harmonic motions of spherical and toroidal surfaces can be deformed non-locally without loosing the existence of infinitely many constants of the motion.

R. W. Gebert

A recently found new free field realization of the affine Sugawara operators at arbitrary level is reviewed, which involves exponentials of the well-known DDF operators in string theory.

F. Antonuccio, S. Pinsky

We consider a dimensional reduction of 3+1 dimensional SU(N) Yang-Mills theory coupled to adjoint fermions to obtain a class of 1+1 dimensional matrix field theories. We derive the quantized light-cone Hamiltonian in the light-cone gauge A_- = 0 and large-N limit, and then solve for the masses, wavefunctions and structure functions of the color singlet ``mes

D. Karczewska, R. Manka

A numerical study of static, spherically symmetric sphaleron solutions in the standard model coupled to the dilaton field is presented. We show that sphaleron is surrounded by strong dilaton cloud which vanishes inside the sphaleron.

G. X. Ju, J. F. Cai, H. Y. Guo, K. Wu

On the basis of graded RTT formalism,the defining relation of the super-Yangian Y(gl(1|1)) is derived and its oscillator realization is constructed.

M. J. Duff, J. T. Liu, J. Rahmfeld

As a further test of the conjectured equivalence of string states and extremal black holes, we compute the dipole moments of black holes with arbitrary spin and superspin in D=4,N=4 supergravity coupled to 22 vector multiplets and compare them with the dipole moments of states in the heterotic string on $T^6$ or the Type IIA string on $K3 \times T^2$. Starti

Renata Kallosh

The Hamiltonian of the wrapping and KK modes of the supermembrane is identified with the SL(2, Z) symmetric axion-dilaton black hole mass formula. It means that the supermembrane with KK modes wrapped $m$ times around the space-time torus of compactified dimensions induces the superpotential breaking spontaneously N=2 down to N=1 SUSY. The supersymmetry brea

Abdellatif Abada, Michael C. Birse

In the framework of the linear sigma model, we study the time evolution of a system of classical $σ$ and pion fields coupled to quarks. For this purpose we solve numerically the classical transport equation for relativistic quarks coupled to the nonlinear Klein-Gordon equations for the meson fields. We examine evolution starting from variety of initial condi

C. M. Maekawa, M. R. Robilotta

We study the interactions of an elementary pion with a nucleon made of constituent quarks and show that the enforcement of chiral symmetry requires the use of a two-body operator, whose form does not depend on the choice of the pion-quark coupling. The coordinate space NN effective potential in the pion exchange channel is given as a sum of terms involving t

S. Scherer

Two different topics relevant for DA$Φ$NE and CEBAF, respectively, are covered. First we analyze the rare radiative eta decay mode $η\toππγγ$ within the framework of chiral perturbation theory at ${\cal O}(p^4)$. We then discuss virtual Compton scattering off the nucleon at low energies. Predictions for the two spin-independent generalized polarizabilities a

J. Gluza, M. Zralek

The production of heavy and light neutrinos in $e^+e^-$ future colliders is considered. The cross section for the process $e^+e^- \rightarrow νN$ and then the heavy neutrino decay $N \rightarrow W^{\pm} e^{\mp}$ is determined for experimentally possible values of mixing matrix elements. The bound on the heavy neutrino-electron mixing is estimated in models w

J. Bartels, M. G. Ryskin

We discuss the space-time picture of scattering amplitudes with single and double ladder exchange in perturbative QCD. Particular emphasis is given to the Abramovsky Gribov Kanchelli (AGK) rules which describe the relative contributions of the diffractive dissociation and processes with other multiplicities to the elastic scattering amplitude. Inside the Pom

Mayumi Aoki, Noriyuki Oshimo, Akio Sugamoto

We study the baryon asymmetry of the universe in the supersymmetric standard model (SSM). At the electroweak phase transition, the fermionic partners of the charged SU(2) gauge bosons and Higgs bosons are reflected from or transmitted to the bubble wallof the broken phase. Owing to a physical complex phase in their mass matrix, these reflections and transmis

V. I. Shevchenko

Starting from the gauge-invariant quark-antiquark Green function the expression for the nonrelativistic meson scattering amplitude is obtained and the nonperturbative form of this amplitude is discussed.

W. Kerler, C. Rebbi, A. Weber

We present a detailed study of the properties of the phase transition in the four-dimensional compact U(1) lattice gauge theory supplemented by a monopole term, for values of the monopole coupling $λ$ such that the transition is of second order. By a finite size analysis we show that at $λ= 0.9$ the critical exponent is already characteristic of a second-ord

X. Martin, A. Vilenkin

Monopole-antimonopole pairs connected by strings can be formed as topological defects in a sequence of cosmological phase transitions. Such hybrid defects typically decay early in the history of the universe but can still generate an observable background of gravitational waves. We study the spectrum of gravitational radiation from these objects both analyti

D. V. Gal'tsov, P. S. Letelier

Dilaton-axion gravity with $p U(1)$ vector fields is studied on space-times admitting a timelike Killing vector field. Three-dimensional sigma-model is derived in terms of Kähler geometry, and holomorphic representation of the SO(2,2+p) global symmetry is constructed. A general static black hole solution depending on $2p+5$ parameters is obtained via SO(2,2+

Yu. P. Rybakov, B. Saha, G. N. Shikin

Exact self-consistent particle-like solutions with spherical and/or cylindrical symmetry to the equations governing the interacting system of scalar, electromagnetic and gravitational fields have been obtained. As a particular case it is shown that the equations of motion admit a special kind of solutions with sharp boundary known as droplets. For these solu

Fredrik Ståhl

We study local variations of causal curves in a space-time with respect to b-length (or generalised affine parameter length). In a convex normal neighbourhood, causal curves of maximal metric length are geodesics. Using variational arguments, we show that causal curves of minimal b-length in sufficiently small globally hyperbolic sets are geodesics. As an ap

A. O. Barvinsky, A. Yu. Kamenshchik, I. V. Mishakov

We give a detailed presentation of a recently proposed mechanism of generating the energy scale of inflation by loop effects in quantum cosmology. We discuss the quantum origin of the early inflationary Universe from the no-boundary and tunneling quantum states and present a universal effective action algorithm for the distribution function of chaotic inflat

John Lott

We define extensions of the $L^2$-analytic invariants of closed manifolds, called delocalized $L^2$-invariants. These delocalized invariants are constructed in terms of a nontrivial conjugacy class of the fundamental group. We show that in many cases, they are topological in nature. We show that the marked length spectrum of an odd-dimensional hyperbolic man

Maurice Kibler

Hurwitz transformations are defined as specific automorphisms of a Cayley-Dickson algebra. These transformations generate quadratic and nonquadratic forms. We investigate here the Hurwitz transformations corresponding to Cayley-Dickson algebras of dimensions 2m = 2, 4 and 8. The Hurwitz transformations which lead to quadratic forms are discussed from geometr

S. Sakhi

An interacting double layer system, with uniform positive background, is studied at finite temperature in the presense of a strong magnetic field corresponding to half filling in each layer. By mapping this system to composite fermions in zero field, we investigate the momentum transfer rate between the layers. As a result of the residual gauge interactions,

Michel Bockstedte, Matthias Scheffler

Ab initio molecular dynamics simulations are employed to investigate the dominant migration mechanism of the gallium vacancy in gaas as well as to assess its free energy of formation and the rate constant of gallium self-diffusion. our analysis suggests that the vacancy migrates by second nearest neighbour hops. the calculated self-diffusion constant is in g

Osamu Koseki, Fumitaka Matsubara

We have proposed a cluster heat bath(CHB) method of a quasi-one dimensional Ising model and demonstrated that it reproduces the exact results of the two dimensional Ising model with axially anisotropic exchange interactions. The point of the method is to select one of the equilibrium spin configurations of each of the chains which are subjected by effective

J. Esser, U. Nowak, K. D. Usadel

Exact ground states are calculated with an integer optimization algorithm for two and three dimensional site-diluted Ising antiferromagnets in a field (DAFF) and random field Ising ferromagnets (RFIM). We investigate the structure and the size-distribution of the domains of the ground state and compare it to earlier results from Monte Carlo simulations for f

Uwe Girlich, Meik Hellmund

We estimate the composite fermion effective mass for a general two particle potential r^{-α} using exact diagonalization for polarized electrons in the lowest Landau level on a sphere. Our data for the ground state energy at filling fraction ν=1/2 as well as estimates of the excitation gap at ν=1/3, 2/5 and 3/7 show that m_eff \sim α^{-1}.

F. M. Izrailev, T. Kottos, A. Politi, G. P. Tsironis

We study numerically the evolution of wavepackets in quasi one-dimensional random systems described by a tight-binding Hamiltonian with long-range random interactions. Results are presented for the scaling properties of the width of packets in three time regimes: ballistic, diffusive and localized. Particular attention is given to the fluctuations of packet

J. Shiraishi, M. Kohmoto, Y. S. Wu

Quasiparticles of the fractional quantum Hall systems obey fractional (including mutual) exclusion statistics. In this note we study the effects of exclusion statistics on thermal activation of quasiparticle pairs in the approximation of generalized ideal gas. The distribution function for thermally activated quasiparticles is found explicitly for the statis

E. Brezin, S. Hikami

We review the existing results on the scaling dimensions of operators with more than two derivatives in the non-linear sigma models. We argue that the speculations on the relevance of these operators, and correspondingly on the breakdown of the $(d-2)$ expansion for the classical Heisenberg model, or for the one-parameter scaling theory of localization, are

M. Jost, K. D. Usadel

We study the kinetic roughening of a driven domain wall between spin-up and spin-down domains for a model with non-conserved order parameter and quenched disorder. To understand the scaling behavior of this interface we construct an equation of motion and study it theoretically.

Andreas Fledderjohann, Claudius Gros

We study numerically the dimerized Heisenberg model with frustration appropriate for the quasi-1D spin-Peierls compound CuGeO$_3$. We present evidence for a bound state in the dynamical structure factor for any finite dimerization $δ$ and estimate the respective spectral weight. For the homogeneous case ($δ=0$) we show that the spin-wave velocity $v_s$ is re

M. P. Joy

A three species food chain model is studied analytically as well as numerically. Integrability of the model is studied using Painleve analysis while chaotic behaviour is studied using numerical techniques, such as calculation of Lyapunov exponents, plotting the bifurcation diagram and phase plots. We correct and critically comment on the wrong results report

Wendy L. Freedman

Recent developments in the determination of H0 are reviewed in the context of the 3 following questions: 1) What is required to measure an accurate value of H0? Given the wide range of H0 values quoted in the current literature, is there any evidence that the situation has changed very much at all in the last couple of decades? And 3), is a measurement of H0

Richard Henriksen, Lawrence M. Widrow

We consider the evolution of an initially cold, spherically symmetric system of self-gravitating particles. At early times the system undergoes self-similar collapse of the type described by Fillmore & Goldreich and Bertschinger. This stage of phase mixing soon gives way to a period of violent relaxation driven by an instability in the similarity solution. T

Claude R. Canizares, David A. Buote

We summarize a series of papers reporting studies of the ellipticities of X-ray images of five Abell clusters and two early type galaxies to learn about the shape of the gravitational potential and the underlying matter distributions. For the clusters we find the dark matter is centrally concentrated with ellipticity $ε_{DM} \sim 0.5$. For the galaxies we fi

Dennis Zaritsky, Amy E. Nelson, Julianne J. Dalcanton, Anthony H. Gonzalez

We present the first high redshift (0.3 < z < 1.1) galaxy clusters found by systematically identifying optical low surface brightness fluctuations in the background sky. Using spectra obtained with the Keck telescope and I-band images from the Palomar 1.5m telescope, we conclude that at least eight of the ten candidates examined are high redshift galaxy clus

A. Vidal-Madjar, R. Ferlet, M. Lemoine

We review the status of the measurements of the deuterium abundance from the local interstellar medium to the solar system and high redshifts absorbers toward quasars. We present preliminary results toward a white dwarf and a QSO. We conclude that the deuterium evolution from the Big-Bang to now is still not properly understood.

Stacy McGaugh, Erwin de Blok

The gas mass fraction (fg) of spiral galaxies is strongly correlated with the central surface brightness of their disks. There exist many dim galaxies with long gas consumption time scales and fg > 0.5. This resolves the gas consumption paradox. The surface density of gas follows the optical surface brightness, but does not vary by as large a factor. This is

Rob P. Olling

In a previous paper (Paper I) a method was developed to determine the shapes of dark matter halos of spiral galaxies from the flaring and velocity dispersion of the gas layer. Here I present the results for the almost edge-on Scd galaxy NGC 4244 (Paper II Paper III) and preliminary results for the Milky Way. NGC 4244&#39;s dark matter halo is found to be hig

Stephen Hancock, Graca Rocha

Cosmological theories for the origin and evolution of structure in the Universe are highly predictive of the form of the angular power spectrum of cosmic microwave background fluctuations. We present new results from a comprehensive study of CMB observations which provide the first measurements of the power spectrum all the way down to angular scales of ~10

Andreas Albrecht

I discuss the origin of the ``Sakharov oscillations&#39;&#39; (or ``secondary Doppler peaks&#39;&#39;) in standard angular power spectra of the Cosmic Microwave Background anisotropies calculated for inflationary models. I contrast this with the production of CMB anisotropies in `active&#39; models and argue that the presence or absence of Sakharov oscillati

S. Pellegrini, E. V. Held, L. Ciotti

Long slit spectroscopic data for 7 early-type galaxies with X-ray emission have been analyzed to derive velocity dispersion and radial velocity profiles. Major axis rotation curves out to $R\sim R_e$ are presented. Adding these new data to those available in the literature, we have built a sample of early-type galaxies with detected X-ray emission and known

H. J. Haubold, A. M. Mathai

Nuclear reactions govern major aspects of the chemical evolution od galaxies and stars. Analytic study of the reaction rates and reaction probability integrals is attempted here. Exact expressions for the reaction rates and reaction probability integrals for nuclear reactions in the case of nonresonant, modified nonresonant, screened nonresonant and resonant

Alexander Givental

A generalization of the mirror conjecture is proven for the manifolds of complete flags in C^n.

Kefeng Liu

In this paper we continue our study on the moduli spaces of flat G-bundles, for any semi-simple Lie group G, over a Riemann surface by using heat kernel and Reidemeister torsion. Formulas for intersection numbers on the moduli spaces over a Riemann surface with several boundary components, over non-orientable Riemann surfaces are obtained. Some general vanis

Robert A. Malaney

Using the redshift evolution of the cosmic gas, as inferred from QSO absorption line studies, we calculate the past supernova rate and the relic supernova neutrino background. Using this new technique we find the predicted relic neutrino flux at low energies to be at least an order of magnitude below previous estimates. We argue that the evolution of the cos

D. J. Broadhurst, D. Kreimer

At four loops there first occurs a test of the four-term relation derived by the second author in the course of investigating whether counterterms from subdivergence-free diagrams form a weight system. This test relates counterterms in a four-dimensional field theory with Yukawa and $ϕ^4$ interactions, where no such relation was previously suspected. Using i

D. Kreimer

We find that the overall UV divergences of a renormalizable field theory with trivalent vertices fulfil a four-term relation. They thus come close to establish a weight system. This provides a first explanation of the recent successful association of renormalization theory with knot theory.

A. O. Barvinsky

Geometric properties of operators of quantum Dirac constraints and physical observables are studied in semiclassical theory of generic constrained systems. The invariance transformations of the classical theory -- contact canonical transformations and arbitrary changes of constraint basis -- are promoted to the quantum domain as unitary equivalence transform

Lu-Ming Duan, Guang-Can Guo

A simple approach is proposed for the quantization of the electromagnetic field in nonlinear and inhomogeneous media. Given the dielectric function and nonlinear susceptibilities, the Hamiltonian of the electromagnetic field is determined completely by this quantization method. From Heisenberg&#39;s equations we derive Maxwell&#39;s equations for the field o

T. H. Baker, P. J. Forrester

We investigate some properties of non-symmetric Jack, Hermite and Laguerre polynomials which occur as the polynomial part of the eigenfunctions for certain Calogero-Sutherland models with exchange terms. For the non-symmetric Jack polynomials, the constant term normalization ${\cal N}_η$ is evaluated using recurrence relations, and ${\cal N}_η$ is related to

Bodo Pareigis

The set of primitive elements of a Hopf algebra in the braided category of group graded vector spaces (with a commutative group) carry the structure of a generalized Lie algebra. In particular the graded derivations of an associative algebra carry this Lie algebra structure. The Lie multiplications consist of certain n-ary partially defined multiplications s

H. Awata, H. Kubo, S. Odake, J. Shiraishi

We review the W_N algebra and its quantum deformation, based on free field realizations. The (quantum deformed) W_N algebra is defined through the (quantum deformed) Miura transformation, and its singular vectors realize the Jack (Macdonald) polynomials. (Talk at the Nankai-CRM joint meeting on ``Extended and Quantum Algebras and their Applications to Physic

R. Brockmann, R. Machleidt

In this review, we give a thorough introduction into the Dirac-Brueckner approach including the mathematical details of the formalism involved. Furthermore, we present results for nuclear matter, NN scattering in the nuclear medium, and finite nuclei.

Argimiro A. Arratia-Quesada, Iain A. Stewart

We answer a question posed by Makowsky and Pnueli and show that the logic $(\pm\mbox{HEX})^\ast[\mbox{FO}_s]$, where HEX is the operator (i.e., uniform sequence of Lindström quantifiers) corresponding to the well-known {\bf PSPACE}-complete decision problem Generalized Hex, collapses to the fragment $\mbox{HEX}^1[\mbox{FO}_s]$ and, moreover, that this logic

M. Khorrami, M. Alimohammadi

Using the path integral method, we calculate the partition function and the generating functional (of the field strengths) of the generalized 2D Yang-Mills theories in the Schwinger--Fock gauge. Our calculation is done for arbitrary 2D orientable, and also nonorientable surfaces.

D. J. Broadhurst, A. V. Kotikov

We simplify, to a single integral of dilogarithms, the least tractable O(1/N^3) contribution to the large-N critical exponent $η$ of the non-linear sigma-model, and hence $ϕ^4$-theory, for any spacetime dimensionality, D. It is the sole generator of irreducible multiple zeta values in epsilon-expansions with $D=2-2ε$, for the sigma-model, and $D=4-2ε$, for $

D. J. Broadhurst

Multiple zeta values (MZVs) are under intense investigation in three arenas -- knot theory, number theory, and quantum field theory -- which unite in Kreimer&#39;s proposal that field theory assigns MZVs to positive knots, via Feynman diagrams whose momentum flow is encoded by link diagrams. Two challenging problems are posed by this nexus of knot/number/fie

David H. Adams

Simplicial versions of topological abelian gauge theories are constructed which reproduce the continuum expressions for the partition function and Wilson expectation value of linked loops, expressible in terms of R-torsion and linking numbers respectively. The new feature which makes this possible is the introduction of simplicial fields (cochains) associate

C. Lourenco

The present knowledge on hard processes in the context of heavy ion collisions is reviewed, with particular emphasis on J/psi production. The p-A data on charmonia production from Fermilab experiments is shown to be in excelent agreement with the p-A data collected at CERN. The simultaneous analysis of all existing p-A data reaches a precision which allows u