February 1997 arXiv papers — page 7

R. P. van der Marel, P. T. de Zeeuw, H. W. Rix

We have obtained spectra through small apertures centered on the nuclear region and major axis of M32, with the HST/FOS. A detailed analysis and reduction of the data is presented, including: (i) new calibrations and modeling of the FOS aperture sizes, PSF and line-spread-functions; (ii) determination of the aperture positioning for each observation; and (ii

Duncan A. Forbes, Jean P. Brodie, Carl Grillmair

Perhaps the most noteworthy of recent findings in extragalactic globular cluster (GC) research are the multimodal GC metallicity distributions seen in massive early-type galaxies. We explore the origin of these distinct GC populations, the implications for galaxy formation and evolution, and identify several new properties of GC systems. First, when we separ

Alejandro Gonzalez

We calculate the strength of the tidal field produced by the large-scale density field acting on primordial density perturbations in power law models. By analysing changes in the orientation of the deformation tensor, resulted from smoothing the density field on different mass scales, we show that the large-scale tidal field can strongly affect the morpholog

Massimo Ricotti, Andrea Ferrara, Francesco Miniati

We present a study of the kinetic energy dissipation in interstellar cloud collisions. The main aim is to understand the dependence of the elasticity (defined as the ratio of the final to the initial kinetic energy of the clouds) on the velocity and mass ratio of the colliding clouds, magnetic field strength, and gas metallicity for head-on collisions. The p

L. Verdes-Montenegro, A. del Olmo, J. Perea, E. Athanassoula

We analyze the morphology and dynamics of the galaxies of the Hickson 96 compact group by means of deep CCD images in the B, V and R photometric bands and long-slit spectroscopy. The four galaxies of this spiral rich group show signs of gravitational interaction. Two long tails come out from the contact region of the close pair H96ac. It is also there where

S. V. Krasnikov

A time machine (TM) is constructed whose creating in contrast to all TMs known so far requires neither singularities, nor violation of the weak energy condition (WEC). The spacetime exterior to the TM closely resembles the Friedmann universe.

Jorge L. Lopez, D. V. Nanopoulos, Raghavan Rangarajan

We calculate the electroweak-like one-loop supersymmetric contributions to the rare and flavor-violating decay of the top quark into a charm quark and a gauge boson: $t->c V$, with $V=γ,Z,g$. We consider loops of both charginos and down-like squarks (where we identify and correct an error in the literature) and neutralinos and up-like squarks (which have not

Daniel P. Arovas, Martin Janssen, Boris Shapiro

We study a number of hierarchical network models related to the Chalker-Coddington model of quantum percolation. Our aim is to describe the physics of the quantum Hall transition. The hierarchical network models are constructed by combining series and parallel composition of quantum resistors. The localization-delocalization transition occurring in these mod

H. M. Antia

Gravitational collapse of a spherically symmetric cloud has been extensively studied to investigate the nature of resulting singularity. However, there has been considerable debate about the admissibility of certain initial density distributions. Using the Newtonian limit of the equations governing collapse of a fluid with an equation of state p=p(ρ) it is s

H. F. Chau

I construct a quantum error correction code (QECC) in higher spin systems using the idea of multiplicative group character. Each $N$ state quantum particle is encoded as five $N$ state quantum registers. By doing so, this code can correct any quantum error arising from any one of the five quantum registers. This code generalizes the well-known five qubit per

Othmar Brodbeck, Norbert Straumann

The existence of normalizable zero modes of the twisted Dirac operator is proven for a class of static Einstein-Yang-Mills background fields with a half-integer Chern-Simons number. The proof holds for any gauge group and applies to Dirac spinors in an arbitrary representation of the gauge group. The class of background fields contains all regular, asymptoti

T. Hurth, P. van Nieuwenhuizen, C. R. Preitschopf, A. Waldron

We analyze a new MacDowell-Mansouri $R^2$-type supergravity action based on the superalgebra Osp(1|8). This contribution summarizes the work of hep-th/9702052.

Irina Shchepochkina

Dynkin's classification of maximal subalgebras of simple finite dimensional complex Lie algebras is generalized to Lie subsuperalgebras of the general linear Lie superalgebras.

Irina Shchepochkina

The five simple exceptional complex Lie superalgbras of vector fields are described. One of them is new; the other four are explicitely described for the first time. All of the exceptional Lie superalgebras are obtained with the help of the Cartan prolongation or a generalized prolongation. The description of several of the exceptional Lie superalgebras is a

Pavel Grozman, Dimitry Leites, Irina Shchepochkina

We define and describe simple complex Lie superalgbras of vector fields on "supercircles" - simple stringy superalgebras. There are four series of such algebras and four exceptional stringy superalgebras. The 13 of the simple stringy Lie superalgebras are distinguished: only they have nontrivial central extensions; since two of the distinguish algebr

V. M. Malkin

The scale dependent intermittency exponents in developed hydrodynamic turbulence are calculated assuming a natural hierarchy of correlations in the turbulence. The major correlations are taken into account explicitly, while the remaining small correlations are considered as perturbations. The results agree very well with the currently available experimental

A. Lazarian, W. G. Roberge

We present an exact formulation of the physics of Barnett relaxation. Our formulation is based on a realistic kinetic model of the relaxation mechanism which includes the alignment of the grain angular momentum in body coordinates by Barnett dissipation, disalignment by thermal fluctuations, and coupling of the angular momentum to the gas via gas damping. We

A. Lazarian

Paramagnetic alignment of thermally rotating oblate dust grains is studied analytically for finite ratios of grain to gas temperatures. For such ratios, the alignment of angular momentum J in respect to the grain axis of maximal inertia is only partial. We treat the alignment of J using perturbative methods and disentangle the problem of J alignment in grain

A. Lazarian

The measures of mechanical alignment were obtained for both prolate and oblate grains when their temperature is comparable with grain kinetic energy devided by k, the Boltzmann constant. For such grains, the alignment of angular momentum, J, with the axis of maximal inertia, a, is only partial. This substantially alters the alignment as compared with the res

Hagai El-Ad, Tsvi Piran

Voids are the most prominent feature of the LSS of the universe. Still, they have been generally ignored in quantitative analysis of it, essentially due to the lack of an objective tool to identify and quantify the voids. To overcome this, we present the Void-Finder algorithm, a novel tool for objectively quantifying galaxy voids. The algorithm classifies ga

Saurabh D. Rindani, Michael M. Tung

The effect of anomalous chromoelectric couplings of the gluon to the top quark are considered in e+ e- --> t tbar. The total cross section, as well as t and tbar polarizations are calculated to order alpha_s in the presence of the anomalous couplings. One of the two linear combinations of t and tbar polarizations is CP even, while the other is CP odd. Limits

William Fulton

We introduce polynomials that represent general degeneracy loci for maps of vector bundles. These polynomials specialize to the known classical and quantum forms of single and double Schubert polynomials. This is the final version of the paper, to appear in Duke Math. J. The results are strengthened because Lakshmibai and Magyar have proved a conjecture from

Eligio Lisi, Daniele Montanino

We present a simple and accurate method for computing analytically the regeneration probability of solar neutrinos in the Earth. We apply this method to the calculation of several solar model independent quantities than can be measured by the SuperKamiokande and Sudbury Neutrino Observatory experiments.

Arnold E. Sikkema, Ian Affleck, Steven R. White

We show that the Kondo chain away from half-filling has a spin gap upon the introduction of an additional direct Heisenberg coupling between localized spins. This is understood in the weak-Kondo-coupling limit of the Heisenberg-Kondo lattice model by bosonization and in the strong-coupling limit by a mapping to a modified t-J model. Only for certain ranges o

Stefan Boettcher

Aging refers to the property of two-time correlation functions to decay very slowly on (at least) two time scales. This phenomenon has gained recent attention due to experimental observations of the history dependent relaxation behavior in amorphous materials (``Glasses'') which pose a challenge to theorist. Aging signals the breaking of time-transla

Naoki Mizutani, Hirofumi Yamada

We apply a recently proposed approximation method to the evaluation of non-Gaussian integral and anharmonic oscillator. The method makes use of the truncated perturbation series by recasting it via the modified Laplace integral representation. The modification of the Laplace transformation is such that the upper limit of integration is cut off and an extra t

Tapani Hyttinen, Saharon Shelah

We show that if M is a stable unsuperstable homogeneous structure, then for most kappa < |M|, the number of elementary submodels of M of power kappa is 2^kappa .

Patrice Le Calvez, Marco Martens, Charles Tresser, Patrick A. Worfolk

Pecora and Carroll presented a notion of synchronization where an (n-1)-dimensional nonautonomous system is constructed from a given $n$-dimensional dynamical system by imposing the evolution of one coordinate. They noticed that the resulting dynamics may be contracting even if the original dynamics are not. It is easy to construct flows or maps such that no

Armando Antillon, Joaquin Escalona, Manuel Torres

We study the structure and properties of vortices in a recently proposed Abelian Maxwell-Chern-Simons model in $2 +1 $ dimensions. The model which is described by gauge field interacting with a complex scalar field, includes two parity and time violating terms: the Chern-Simons and the anomalous magnetic terms. Self-dual relativistic vortices are discussed i

M. Biyajima, N. Suzuki, A. Ohsawa

Pseudo-rapidity distributions of high multiplicity JACEE events ( Ca-C, Si-AgBr and G27) and Texas Lone Star (TLS) event are analysed by the wavelet transform method. Using the Daubechies&#39; waveltes, $D_4, D_6, D_8,$ and $ D_{10} $, wavelet spectra of those events are calculated. Two JACEE events are compared with the simulation calculations. We discuss h

T. Osada, M. Biyajima, G. Wilk

Recently we have found that integral of the squared Coulomb wave function describing systemcomposed of charged pion and central charged fragment $Z_{eff}$ protons, $|ψ_r(r)|^2$, times pion source function $ρ(r)$ (of the size $β$), $\intdr |ψ_r(r)|^2 ρ(r)$, shows a quasiscaling behavior. This is approximately invariant under the following transformation: $(β,

M. Biyajima, T. Mizoguchi, T. Osada, G. Wilk

We are presenting here the new formulae for Bose-Einstein correlations (BEC) which contain effects of final state interactions (FSI) of both strong (in $s$-wave) and electromagnetic origin. We demonstrate the importance of FSI in BEC by analysing data for $e^+e^-$ annihilation and for heavy collisions. The inclusion of FSI results in the practical eliminatio

Peter Lichard

The hypothesis is scrutinized that the weak interaction of hadronic systems at low energies is dominated by the coupling of the pseudoscalar, vector, and axial-vector mesons to the weak gauge bosons. The strength of the weak coupling of the rho(770) meson is uniquely determined by vector-meson dominance in electromagnetic interactions; flavor and chiral symm

F. Berends, M. Dubinin

We consider the possibility of experimental observation of flavor-diagonal and helicity conserving contact terms in the four fermion reactions e^+ e^- -> e^+ e^- μ^+ μ^- and e^- q -> e^- μ^+ μ^- q at LEP2 and HERA.

Klaus M. Frahm

We consider the quantum dynamics of a particle in a weakly rough billiard. The Floquet operator for reflection at the boundary is obtained as a unitary band matrix. The resulting dynamics in angular momentum space can be treated in the framework of the one-dimensional supersymmetric nonlinear sigma model. We find analytically localization and the correspondi

M. R. Norman, H. Ding, J. C. Campuzano, T. Takeuchi

Photoemission spectra of Bi_2Sr_2CaCu_2O_{8+delta} below T_c show two features near the (pi,0) point of the zone: a sharp peak at low energy and a higher binding energy hump. We find that the sharp peak persists at low energy even as one moves towards (0,0), while the broad hump shows significant dispersion which correlates well with the normal state dispers

Yuri G. Prokhorov

In this paper we study a local structure of extrmal contractions $f\colon X\to S$ from threffolds $X$ with only terminal singularities onto a surface $S$. If the surface $S$ is non-singular and $X$ has a unique non-Gorenstein point on a fiber we prove that either the linear system $|-K_X|$, $|-2K_X|$ or $|-3K_X|$ contains a &#34;good&#34; divisor.

S. P. Strong

We show that a transformed Caldeira-Leggett Hamltonian has two distinct families of fixed points, rather than a single unique fixed point as often conjectured based on its connection to the anisotropic Kondo model. The two families are distinguished by a sharp qualitative difference in their quantum coherence properties and we argue that this distinction is

Jae-Kwon Kim, D. P. Landau, Matthias Troyer

We present an analysis of high precision Monte Carlo data for the two dimensional S=1/2 quantum Heisenberg antiferromagnet up to $ξ= 95.7(3)$ obtained by the continuous time version of the loop algorithm. Our data are in good agreement with a prediction of the recent theory (Phys. Rev. Lett. vol. 77, 3439 (1996)) in very high temperature regime, but they str

Yan Levin, Marcia C. Barbosa, M. N. Tamashiro

A simple theory of the fluid state of a charged colloidal suspension is proposed. The full free energy of a polyelectrolyte solution is calculated. It is found that the counterions condense onto the polyions forming clusters composed of one polyion and n counterions. The distribution of cluster sizes is determined explicitly. In agreement with the current ex

Robert D. Pisarski, Michel Tytgat

Based upon what is known about the phase transition(s) of an SU(3) gauge theory, we argue that in a SU(N_c) gauge theory without quarks, at nonzero temperature the deconfining phase transition is of second order when N_c \geq 4.

Jens Schmalzing, Thomas Buchert

The genus statistics of isodensity contours has become a well-established tool in cosmology. In this Letter we place the genus in the wider framework of a complete family of morphological descriptors. These are known as the Minkowski functionals, and we here apply them for the first time to isodensity contours of a continuous random field. By taking two equi

Eizou Umezawa

We study Sogami&#39;s generalized covariant derivative method for a $SU(2)_{L} \times SU(2)_{R} \times U(1)_{B-L} \times SU(3)_{c}$ model that contains bi-doublet and triplet Higgs bosons. In particular, a detailed study is made on the minimization conditions of the Higgs potential. It is known that a minimization condition and certain phenomenology for a ex

J G Rarity, P R Tapster, R Loudon

When a one-photon state is mixed with a (separate) weak coherent state at a beamsplitter the probability for detecting one photon in each beamsplitter output approaches zero due to destructive interference. We demonstrate this non-classical interference effect using pulse-gated single photons and weak mode-locked laser pulses.

T. Shigehara, Taksu Cheon

We examine the spectral properties of three-dimensional quantum billiards with a single pointlike scatterer inside. It is found that the spectrum shows chaotic (random-matrix-like) characteristics when the inverse of the formal strength $\bar{v}^{-1}$ is within a band whose width increases parabolically as a function of the energy. This implies that the spec

Angus F. Nicholson, Dallas C. Kennedy

A simple, anomaly-free chiral gauge theory can be perturbatively quantised and renormalised in such a way as to generate fermion and gauge boson masses. This development exploits certain freedoms inherent in choosing the unperturbed Lagrangian and in the renormalisation procedure. Apart from its intrinsic interest, such a mechanism might be employed in elect

Maarten Golterman, Ka Chun Leung

In this paper we use one-loop chiral perturbation theory in order to compare lattice computations of the K+ to pi+ pi0 decay amplitude with the experimental value. This makes it possible to investigate three systematic effects that plague lattice computations: quenching, finite-volume effects, and the fact that lattice computations have been done at unphysic

O. V. Radko, A. A. Vladimirov

Intrinsic Hopf algebra structure of the Woronowicz differential complex is shown to generate quite naturally a bicovariant algebra of four basic objects within a differential calculus on quantum groups -- coordinate functions, differential 1-forms, Lie derivatives, and inner derivations -- as the cross-product algebra of two mutually dual graded Hopf algebra

Yasuhiko Yamada

A $q$-analog of the Clebsch Gordan rules for the tensor products of the fundamental representations of Yangian is introduced. Its relation to the crystal base theory and application to the spinon character formulas are discussed in case of $C_2^{(1)}$ explicitly.

E. A. Kolganova, A. K. Motovilov

Algorithm, based on explicit representations for analytic continuation of the T-matrix Faddeev components on unphysical sheets, is worked out for calculations of resonances in the three-body quantum problem. According to the representations, poles of the T--matrix, scattering matrix and resolvent on unphysical sheets, interpreted as resonances, coincide with

Gerald A. Miller

A light front treatment of the nuclear wave function is developed and applied, using the mean field approximation, to infinite nuclear matter. The nuclear mesons are shown to carry about a third of the nuclear plus momentum, p+; but their momentum distribution has support only at p+ =0, and the mesons do not contribute to nuclear deep inelastic scattering. T

David G. Madland

Two existing global medium-energy nucleon-nucleus phenomenological optical model potentials are described and compared with experiment and with each other. The first of these employs a Dirac approach (second-order reduction) that is global in projectile energy and projectile isospin and applies to the target nucleus 208-Pb. Here the standard S-V (isoscalar-s

K. Varga, Y. Suzuki

This paper presents a fortran program to solve diverse few-body problems with the stochastic variational method. Depending on the available computational resources the program is applicable for $N=2-3-4-5-6-...$-body systems with $L=0$ total orbital momentum. The solution with the stochastic variational method is ``automatic&#39;&#39; and universal. One defi

H. M. Chan, S. T. Tsou

It is shown that the operator $B(C) = Tr [P \exp i \tilde{g} \oint \tilde{A}_i(x) dx^i]$ constructed with the recently derived dual potential $\tilde{A}(x)$ and a coupling $\tilde{g}$ related to $g$ by the Dirac quantization condition satisfies the correct commutation relation with the Wilson operator $Tr [P \exp ig \oint A_i(x) dx^i]$ as required by &#39;t

Hwang-hyun Kwon

The role of instantons in three dimensional N=2 supersymmetric SU(2) Yang-Mills theory is studied, especially in relation to the issue of confinement. The instanton-induced low energy effective action is derived by extending the dilute gas approximation to the super-moduli space of instantons. Following Polyakov&#39;s description of confinement in compact U(

H. Partouche, B. Pioline

We review in detail the recently discovered phenomenon of partial spontaneous breaking of supersymmetry in the case of a N=2 pure gauge U(1) theory, and recall how the standard lore no-go theorem is evaded. We discuss the extension of this mechanism to theories with charged matter, and surprisingly find that the gauging forbids the existence of a magnetic Fa

Luca Lusanna

A review is given of the status of the program of classical reduction to Dirac&#39;s observables of the four interactions (standard SU(3)xSU(2)xU(1) particle model and tetrad gravity) with the matter described either by Grassmann-valued fermion fields or by particles with Grassmann charges.

J. Alfaro, R. Medina, L. F. Urrutia

In this paper we obtain the orthogonality relations for the supergroup U(m|n), which are remarkably different from the ones for the U(N) case. We extend our results for ordinary representations, obtained some time ago, to the case of complex conjugated and mixed representations. Our results are expressed in terms of the Young tableaux notation for irreducibl

P. S. Howe, E. Sezgin, P. C. West

The equations of motion for a self-interacting self-dual tensor in six dimensions are extracted from the equations describing the M-theory five-brane. These equations are presented in a self-contained, six-dimensional Lorentz-covariant form. In particular, it is shown that the field-strength tensor satisfies a non-linear generalised self-duality constraint.

David Berenstein, Richard Corrado

We demonstrate the precise numerical correspondence between long range scattering of supergravitons and membranes in supergravity in the infinite momentum frame and in M(atrix)-Theory, both in 11 dimensions and for toroidal compactifications. We also identify wrapped membranes in terms of topological invariants of the vector bundles associated to the field t

F. del Aguila, A. Culatti, R. Munoz-Tapia, M. Perez-Victoria

The method of differential renormalization is extended to the calculation of the one-loop graviton and gravitino corrections to $(g-2)_l$ in unbroken supergravity. Rewriting the singular contributions of all the diagrams in terms of only one singular function, U(1) gauge invariance and supersymmetry are preserved. We compare this calculation with previous on

Hooman Davoudiasl, Adam K. Leibovich

We calculate the perturbative corrections to order α_s^2β_0 to the sum rule derived from the second moment of the time-ordered product of b \to c currents near zero recoil. This sum rule yields a bound on λ_1, the expectation value of the b quark kinetic energy operator inside the B meson. The perturbative corrections significantly weaken the bound relative

A. V. Anisovich, V. V. Anisovich, A. V. Sarantsev

Basing on the previously performed K-matrix analysis of experimental data, we investigate, in the framework of the propagator matrix (D-matrix) technique, the 1100-1900 MeV mass region, where overlapping resonances $f_0(1300)$, $f_0(1500)$, $f_0(1530^{+90}_{-250})$, and $f_0(1780)$ are located. Necessary elements of the D-matrix technique are developed. The

A. A. Andrianov, V. A. Andrianov, D. Ebert, Th. Feldmann

We derive the dimensional non-perturbative part of the QCD effective action for scalar and pseudoscalar meson fields by means of chiral and conformal bosonization. The related structural coupling constants L_5 and L_8 of the chiral lagrangian are estimated using general relations which are valid in a variety of chiral bosonization models without explicit ref

G. Barenboim, J. Bernabeu, M. Raidal

We investigate effects of spontaneous breakdown of CP in $B^0_{d,s}-\overline{B^0}_{d,s}$ systems in left-right symmetric models. Assuming that the left-right contribution to the $B^0-\overline{B^0}$ matrix element $M_{12}$ can be at most equal to the standard model one we obtain a new lower bound, $M_H\gsim 12$ TeV, on the flavour changing Higgs boson mass.

O. G. Tchikilev

It is shown that simple extension of the modified negative binomial distribution describes negatively charged particle multiplicity distributions in e+e- annihilation, measured in the whole phase space, as well as the modified negative binomial.

V. Barger, M. S. Berger, J. F. Gunion, T. Han

Precise determinations of the masses of the $W$ boson and of the top quark could stringently test the radiative structure of the Standard Model (SM) or provide evidence for new physics. We analyze the excellent prospects at a muon collider for measuring $M_W$ and $m_t$ in the $W^+W^-$ and $t\bar t$ threshold regions. With an integrated luminosity of 10 (100)

Roberto Frezzotti, Karl Jansen

We present a simulation algorithm for dynamical fermions that combines the multiboson technique with the Hybrid Monte Carlo algorithm. We find that the algorithm gives a substantial gain over the standard methods in practical simulations. We point out the ability of the algorithm to treat fermion zeromodes in a clean and controllable manner.

The SLD Collaboration, K. Abe et al

We present evidence for leading particle production in hadronic decays of the Z0 boson to light-flavor jets. A polarized electron beam was used to tag quark and antiquark jets, and a vertex detector was employed to reject heavy-flavor events. Charged hadrons were identified with a Cherenkov ring imaging detector. In the quark jets, more high-momentum p, Lamb

Jonathan L. Rosner, John F. Wilkerson

Initial results of a project to detect the radio-frequency pulse associated with extensive air showers of cosmic rays are described briefly. This work is being performed at the CASA/MIA array in Utah, with the intention of designing equipment that can be used in conjunction with the Auger Giant Array proposal.

Lluiís Bel

We propose a distinguished set of positive and negative energy modes of the Klein-Gordon equation as a time independent definition of the vacuum state of a quantized scalar field.

M. E. X. Guimaraes

In the context of the vacuum polarization effect, we consider the backreaction of the energy-momentum tensor of a charged scalar field on the background metric of a cosmic string carrying a magnetic flux $Φ$. Working within the semiclassical approach to the Einstein eqs. we find the first-order (in $\hbar$) metric associated to the magnetic flux cosmic strin

M. Widom, I. Al-Lehyani

Reptation governs motion of long polymers through a confining environment. Slack enters at the ends and diffuses along the polymer as stored length. The rate at which stored length diffuses limits the speed at which the chain can drift. This paper relates the rate of stored length diffusion to the conformation of the tube within which the polymer is confined

Alexandre Diehl, Marcia C. Barbosa, Yan Levin

Sine-Gordon field theory is used to investigate the phase diagram of a neutral Coulomb gas. A variational mean field free energy is constructed and the corresponding phase diagrams in two (2d) and three dimensions (3d) are obtained. When analyzed in terms of chemical potential, the Sine-Gordon theory predicts the phase diagram topologically identical with th

Dror Orgad

The chiral Luttinger model for the edges of the fractional quantum Hall effect is obtained as the low energy limit of the Chern-Simons theory for the two dimensional system. In particular we recover the Kac-Moody algebra for the creation and annihilation operators of the edge density waves and the bosonization formula for the electronic operator at the edge.

Francois David, Bertrand Duplantier, Emmanuel Guitter

We prove the renormalizability of the generalized Edwards model for self-avoiding polymerized membranes. This is done by use of a short distance multilocal operator product expansion, which extends the methods of local field theories to a large class of models with non-local singular interactions. This ensures the existence of scaling laws for crumpled self-

Klaus M. Frahm, Dima L. Shepelyansky

By analytical mapping of the eigenvalue problem in rough billiards on to a band random matrix model a new regime of Wigner ergodicity is found. There the eigenstates are extended over the whole energy surface but have a strongly peaked structure. The results of numerical simulations and implications for level statistics are also discussed.

Scott Dodelson

Anisotropies in the Cosmic Microwave Background (CMB) contain a wealth of information about the past history of the universe and the present values of cosmological parameters. I ouline some of the theoretical advances of the last few years. In particular, I emphasize that for a wide class of cosmological models, theorists can accurately calculate the spectru

G. Fiorentini, B. Ricci

This question, which often comes in when discussing solar neutrinos, is not clearly analysed in any textbook, to our knowledge. In this note we give a simple estimate of the flow time, also reminding its (ir)relevance to the solar neutrino problem.

W. J. Duschl, Peter A. Strittmatter, Peter L. Biermann

We show that the standard model for geometrically thin accretion disks (alpha-disks) leads to inconsistencies if selfgravity plays a role. This problem arises from the parametrization of viscosity in terms of local sound velocity and vertical disk scale height. A viscosity prescription based on turbulent flows at the critical effective Reynolds number allows

Joao Magueijo, Alex Lewin

We present a new tool for relating theory and experiment suited for non-Gaussian theories: non-Gaussian spectra. It does for non-Gaussian theories what the angular power spectrum $C_\ell$ does for Gaussian theories. We then show how previous studies of cosmic strings have over rated their non-Gaussian signature. More realistic maps are not visually stringy.

G. Barbaro, B. M. Poggianti

A spectrophotometric model able to compute the integrated spectrum of a galaxy, including the contribution both of the stellar populations and of the ionized interstellar gas of the HII regions powered by young hot stars, has been used to study several spectral features and photometric quantities in order to derive calibrations of the star formation history

J. Gerssen, K. Kuijken, M. R. Merrifield

Theories of stellar orbit diffusion in disk galaxies predict different rates of increase of the velocity dispersions parallel and perpendicular to the disk plane, and it is therefore of interest to measure the different velocity dispersion components in galactic disks of different types. We show that it is possible to extract the three components of the velo

D. Montes, M. J. Fernandez-Figueroa, E. De Castro, J. Sanz-Forcada

This is the first paper of a series aimed at studying the chromosphere of active binary systems using the information provided for several optical spectroscopic features. Simultaneous H{alpha}, Na I D{1}, D{2}, and He I D{3} spectroscopic observations are reported here for 18 systems. The chromospheric contribution in these lines have been determined using t

Hans-Walter Rix, Tim de Zeeuw, Marcella Carollo, Nicolas Cretton

We describe a powerful technique to model and interpret the stellar line-of-sight velocity profiles of galaxies. Following Schwarzschild&#39;s modeling approach, a representative library of orbits is calculated in a given potential; then the non-negative superposition of these orbits is determined to fit best a given set of observational constraints. Our imp

Steen Hannestad, Jes Madsen

We present a calculation of a neutrino decay scenario in the early Universe. The specific decay is ν_{2} \to ν_{1} + ϕ, where ϕis a boson. If there is a neutrino mass hierarchy, m_{ν_{e}} < m_{ν_μ} < m_{ν_τ}, we show that it is possible to generate stimulated decay and effects similar to atomic lasing without invoking new neutrinos, even starting from identi

Bianca Garilli, Giorgio Sangalli, Stefano Andreon, Dario Maccagni

The Gunn g, r and i CCD images of a representative sample of 17 Brightest Cluster Galaxies (BCM) have been analyzed in order to derive surface brightness and color profiles, together with geometrical parameters like eccentricity and position angle. The sample includes both X-ray and optically selected clusters, ranging in redshift from z=0.049 to z=0.191. We

Crystal L. Martin, Robert C. Kennicutt,

We report measurements of He I 5876 emission from the ionized gas outside the HII regions in three Magellanic irregular galaxies. The mean reddening-corrected He I / H-alpha intensity ratio is 0.041 independent of spatial location within each galaxy. This value is much higher than that measured in the warm ionized medium of the Milky Way and implies the DIG

Gilberto Moretto, Ermanno F. Borra

We investigate whether a three-mirror system, having secondary and the tertiary mirrors with surfaces warped by Zernike polynomials generated by active vase mirrors, is suitable to do the corrections of a fixed parabolic mirror observing at large angles from the zenith. We obtain designs of correctors with remarkable images and control of the distortion of t

Michael Finkelberg, Alexander Kuznetsov

Let $C$ be a smooth projective curve of genus 0. Let $\CB$ be the variety of complete flags in an $n$-dimensional vector space $V$. Given an $(n-1)$-tuple $α\in\BN[I]$ of positive integers one can consider the space $\CQ_α$ of algebraic maps of degree $α$ from $C$ to $\CB$. This space admits some remarkable compactifications $\CQ^D_α$ (Quasimaps), $\CQ^L_α$

Michael J. Pfenning, L. H. Ford

We will apply the quantum inequality type restrictions to Alcubierre&#39;s warp drive metric on a scale in which a local region of spacetime can be considered ``flat&#39;&#39;. These are inequalities that restrict the magnitude and extent of the negative energy which is needed to form the warp drive metric. From this we are able to place limits on the parame

S. A. Dytman, T. P. Vrana, T. S. H. Lee

We present organization and solutions for a new analysis of all $πN$ elastic and the major inelastic channels to extract detailed characteristics of the contributing baryon resonances. This work is based on the work of R. Cutkosky and collaborators at CMU about 20 years ago. The model features analyticity at the amplitude level and unitarity. Results are sim

Nicolas J. Cerf, Richard Cleve

Quantum error-correcting codes are analyzed from an information-theoretic perspective centered on quantum conditional and mutual entropies. This approach parallels the description of classical error correction in Shannon theory, while clarifying the differences between classical and quantum codes. More specifically, it is shown how quantum information theory

H. P. Nilles, S. Stieberger

We derive the universal threshold corrections in heterotic string theory including a continuous Wilson line. Unification of gauge and gravitational couplings is shown to be possible even within perturbative string theory. The relative importance of gauge group dependent and independent thresholds on unification is clarified. Equipped with these results we ca

M. Boyce, J. Treurniet, P. J. S. Watson

It has been shown that the string-flip potential model reproduces most of the bulk properties of nuclear matter, with the exception of nuclear binding. Furthermore, it was postulated that this model with the inclusion of the colour-hyperfine interaction should produce binding. In some recent work a modified version of the string-flip potential model was deve

Claude LeBrun

The Yamabe invariant Y(M) of a smooth compact manifold is roughly the supremum of the scalar curvatures of unit-volume constant-scalar curvature Riemannian metrics g on M. (To be absolutely precise, one only considers constant-scalar-curvature metrics which are Yamabe minimizers, but this does not affect the sign of the answer.) If M is the underlying smooth

Fay Dowker, David Kastor, Jennie Traschen

An expression for the spacetime absorption coefficient of a scalar field in a five dimensional, near extremal black hole background is derived, which has the same form as that presented by Maldacena and Strominger, but is valid over a larger, U-duality invariant region of parameter space and in general disagrees with the corresponding D-brane result. We deve

Malgorzata Rowicka-Kudlicka

A braided category of C*-algebras is constructed. Its objects are C*-algebras endowed with an action of the group R, its morphisms are C*-algebras morphisms intertwining the action of R, the crossed product of its two objects essentially depends on the action of R on considered C*-algebras. Crossed products of any object with the algebra of all continuous va

S. Willenbrock

``Weakly-coupled&#39;&#39; and ``strongly-coupled&#39;&#39; models of electroweak symmetry breaking are introduced by analogy with the Fermi theory of the weak interaction and the low-energy interaction of pions, respectively. The implications of these two classes of models for colliders beyond the LHC and NLC are discussed.

Y. K. Ng, G. Bertelli, C. Chiosi, A. Bressan

Observations of (B-V) colour distributions towards the galactic poles are compared with those obtained from synthetic colour-magnitude diagrams to determine the major constituents in the disc and spheroid. The disc is described with four stellar sub-populations: the young, intermediate, old, and thick disc populations, which have respectively scale heights o