October 1996 arXiv papers — page 8

Chulwoo Jung

We have studied field configurations of the 3-dimensional Georgi-Glashow model which interpolate between the $U(1)$ and the $SU(2)$ limits. In the intermediate region, these configurations contain 't-Hooft--Polyakov monopoles. We use cooling and extremization to find these configurations and investigate their evolution as we adiabatically move towards th

Raphael Bousso

Dilatonic Charged Nariai instantons mediate the nucleation of black hole pairs during extended chaotic inflation. Depending on the dilaton and inflaton fields, the black holes are described by one of two approximations in the Lorentzian regime. For each case we find Euclidean solutions that satisfy the no boundary proposal. The complex initial values of the

Xing Zhuge, Joan M. Centrella, Stephen L. W. McMillan

We calculate the gravitational radiation produced by the coalescence of inspiraling binary neutron stars in the Newtonian regime using 3-dimensional numerical simulations. The stars are modeled as polytropes and start out in the point-mass regime at wide separation. The hydrodynamic integration is performed using smooth particle hydrodynamics (SPH) with Newt

Jolien D. E. Creighton

I generalize the quasilocal formulation of thermodynamics of Brown and York to include dilaton theories of gravity as well as Abelian and Yang-Mills gauge matter fields with possible dilaton couplings. The resulting formulation is applicable to a large class of theories including two-dimensional toy models and the low energy limit of string theory as well as

I. M. Benn, Philip Charlton, Jonathan Kress

By using conformal Killing-Yano tensors, and their generalisations, we obtain scalar potentials for both the source-free Maxwell and massless Dirac equations. For each of these equations we construct, from conformal Killing-Yano tensors, symmetry operators that map any solution to another.

Shou-Cheng Zhang

We show that the complex phase diagram of high $T_c$ superconductors can be deduced from a simple symmetry principle, a $SO(5)$ symmetry which unifies antiferromagnetism with $d$ wave superconductivity. We derive the approximate $SO(5)$ symmetry from the microscopic Hamiltonian and show furthermore that this symmetry becomes exact under the renormalization g

Enrique Diez, Francisco Dominguez-Adame, Enrique Macia, Angel Sanchez

We present a detailed study of the dynamics of electronic wavepackets in Fibonacci semiconductor superlattices, both in flat band conditions and subject to homogeneous electric fields perpendicular to the layers. Coherent propagation of electrons is described by means of a scalar Hamiltonian using the effective-mass approximation. We have found that an initi

F. Borgonovi, D. L. Shepelyansky

We numerically investigate the Anderson transition in an effective dimension $d$ ($3 \leq d \leq 11$) for one particle propagation in a model random and quasiperiodic potential. The found critical exponents are different from the standard scaling picture. We discuss possible reasons for this difference.

Imre Varga, János Pipek, Martin Janssen, Krystian Pracz

Based on differences of generalized Rényi entropies nontrivial constraints on the shape of the distribution function of broadly distributed observables are derived introducing a new parameter in order to quantify the deviation from lognormality. As a test example the properties of the two--measure random Cantor set are calculated exactly and finally using th

Haruhiko Kuroe, Jun-ichi Sasaki, Tomoyuki Sekine, Naoki Koide

We have measured temperature dependence of low-frequency Raman spectra in CuGeO$_3$, and have observed the quasi-elastic scattering in the $(c,c)$ polarization above the spin-Peierls transition temperature. We attribute it to the fluctuations of energy density in the spin system. The magnetic specific heat and an inverse of the magnetic correlation length ca

N. B. Wilding

We review and discuss recent advances in the simulation of bulk critical phenomena in model fluids. In particular we emphasise the extensions to finite-size scaling theory needed to cope with the lack of symmetry between coexisting fluid phases. The consequences of this asymmetry for simulation measurements of quantities such as the particle density and the

G. L. Israel, L. Stella, L. Angelini, N. E. White

We discovered strong 13s X-ray pulsations in the public Rosat PSPC light curve of HD49798, a 1.55d single-component spectroscopic binary containing a hydrogen depleted subdwarf O6 star. We find no evidence for period changes during the about 4hr Rosat pointing. The source X-ray spectrum is extremely soft, with an unabsorbed 0.1-2keV luminosity of a few times

M. L. Montoya, R. Dominguez-Tenreiro, G. Gonzalez-Casado, G. A. Mamon

A statistical method is developed to infer the typical density profiles of poor galaxy systems without resort to binning of data or assuming a given center to each system. The method is applied to the accordant redshift quartets in Hickson's compact groups (HCGs). The distribution of separations in these groups is consistent with a unique generalized mod

A. Iovino, P. Hickson

This paper addresses the long standing question of discordant redshifts in compact groups. We have used an homogenous catalogue of 173 compact groups selected by an automated procedure to objectively predict the fraction of discordant redshifts with high statistical accuracy, and then applied these results to the sample of 92 compact groups in Hickson's

Eduardo Telles, Roberto Terlevich

We present a high spatial resolution CCD surface photometry study in the optical V, R and I broadband filters of a sample of 15 HII galaxies. The colours of the starburst continuum and of the underlying galaxy are measured. The distribution of colours of the underlying galaxy in HII galaxies is similar to the colours of other late type low surface brightness

D. Thompson, F. Mannucci, S. V. W. Beckwith

A narrowband imaging survey of 276 square minutes of arc was carried out at near infrared wavelengths to search for emission line objects at high redshifts. Most of the fields contained a known quasar or radio galaxy at a redshift that placed one of the strong, restframe optical emission lines (H-alpha, [O III], H-beta, or [O II]) in the bandpass of the narr

A. Raga, G. Mellema, P. Lundqvist

We have chosen a reduced set of 18 ionization rate equations (for ions of H, C, N, O, S and Ne), which allow us to obtain a moderately accurate estimate of the non-equilibrium radiative cooling function. We evaluate the accuracy of this approach by comparing our cooling function with previous calculations, computed with a more extended set of ions, for the c

Charles H. Lineweaver, Domingos Barbosa, Alain Blanchard, James G. Bartlett

In this paper we compare data to theory. We use a compilation of the most recent cosmic microwave background (CMB) measurements to constrain Hubble's constant h, the baryon fraction Omega_b, and the cosmological constant lambda. We fit h-, Omega_b- and lambda-dependent power spectra to the data. The models we consider are flat cold dark matter (CDM) domi

H. C. Rosu

Many living organisms on Earth are strongly dependent on water, the natural liquid of the planet. A possible reason for that could be the conjecture of Ryoji Takahashi [Phys. Lett. A 141, 15 (1989)] that water microdrops release negentropy through a phase transition to a phase with zero surface tension. Biological cells could make use of such a phase transit

Michael Bershadsky, Andrei Johansen

We study F-theory on elliptic threefold Calabi-Yau near colliding singularities. We demonstrate that resolutions of those singularities generically correspond to transitions to phases characterized by new tensor multiplets and enhanced gauge symmetry. These are governed by the dynamics of tensionless strings. We also find new transition points which are asso

Adam K. Leibovich

We calculated the polarization of ψ' due to gg \to Q\bar{Q}[^3P_J^(8)]g \to ψ^λcolor-octet quarkonia production. We find that at low transverse momenta the ψ' is unpolarized due to the contributions proportional to the L=S=0 and L=S=1 color-octet matrix elements. As p_\perp increases, the ψ' mesons become 100% polarized, as predicted by fragmenta

Gilad Lifschytz

A zero-brane is used to probe non-threshold BPS bound states of (p, p+2,p+4)-branes. At long distances the stringy calculation agrees with the supergravity calculations. The supergravity description is given, using the interpretation of the D=8 dyonic membrane as the bound state of a two-brane inside a four-brane. We investigate the short distance structure

Albert Schwarz

Infinite-dimensional Grassmannian manifold contains moduli spaces of Riemann surfaces of all genera. This well known fact leads to a conjecture that non-perturbative string theory can be formulated in terms of Grassmannian. We present new facts supporting this hypothesis. In particular, it is shown that Grassmannians can be considered as generalized moduli s

Bryan E. Barmore

The sigma-omega model in mean-field approximation where the meson fields are treated classically, describes much of observed nuclear structure and has been employed to describe the nuclear equation of state up to the quark-gluon phase transition. The acceleration of the meson sources, for example, in relativistic heavy-ion collisions, should result in bremss

Eugene Kogan

General dynamical transport of classical particles in disordered quasi-1D samples is viewed in the framework of scattering approach. Simple equation for the transfer-matrix is obtained within this unified picture. In the case of diffusive transport the solution of this equation exactly coincides with the solution of diffusion equation.

A. A. Andrianov, V. A. Andrianov, V. L. Yudichev

Quark models with four-fermion interaction including derivatives of fields are exploited as prototypes for composite-Higgs extensions of the Standard Model. In the non-trivial case of two- and four-derivative insertions the dynamical breaking of chiral symmetry occurs in two channels, giving rise to two composite Higgs doublets. For special configuration of

Boucif Abdesselam

A two parametric deformation of the enveloping Heisenberg algebra ${\cal H}(4)$ which appear as a combination of the standard and a nonstandard quantization given by Ballesteros and Herranz is defined and proved to be Ribbon Hopf algebra. The universal ${\cal R}$-matrix and its associated quantum group are constructed. New solution of Braid group are obtaine

K. Adel, F. Barreiro, F. J. Ynduráin

We calculate structure functions at small $x$ both under the assumption of a hard singularity (a power behaviour $x^{-λ}, λ$ positive, for $x\rightarrow 0$) or that of a soft-Pomeron dominated behaviour, also called double scaling limit, for the singlet component. A full next to leading order (NLO) analysis is carried for the functions $F_2, F_{\rm Glue}$ an

H. F. Chau

I consider the theory of quantum error correcting code (QECC) where each quantum particle has more than two possible eigenstates. In this higher spin system, I report an explicit QECC that is related to the symmetry group ${\Bbb Z}_2^{\otimes (N-1)} \otimes S_N$. This QECC, which generalizes Shor's simple majority vote code, is able to correct errors ari

Christian Schubert

These two lectures give a pedagogical introduction to the ``string-inspired'' worldline technique for perturbative calculations in quantum field theory. This includes an overview over the present range of its applications. Several examples are calculated in detail, up to the three-loop level. The emphasis is on photon scattering in quantum electrodyn

H. Lu, S. Mukherji, C. N. Pope, K. -W. Xu

We obtain a large class of cosmological solutions in the toroidally-compactified low energy limits of string theories in $D$ dimensions. We consider solutions where a $p$-dimensional subset of the spatial coordinates, parameterising a flat space, a sphere, or an hyperboloid, describes the spatial sections of the physically-observed universe. The equations of

Hong-Chen Fu, Ryu Sasaki

Following the relationship between probability distribution and coherent states, for example the well known Poisson distribution and the ordinary coherent states and relatively less known one of the binomial distribution and the $su(2)$ coherent states, we propose ``interpretation'' of $su(1,1)$ and $su(r,1)$ coherent states ``in terms of probability

Hong-Chen Fu, Ryu Sasaki

`Hypergeometric states', which are a one-parameter generalization of binomial states of the single-mode quantized radiation field, are introduced and their nonclassical properties are investigated. Their limits to the binomial states and to the coherent and number states are studied. The ladder operator formulation of the hypergeometric states is found a

Marcelo R. Ubriaco

We first introduce and discuss the formalism of $SU_q(N)$-bosons and fermions and consider the simplest Hamiltonian involving these operators. We then calculate the grand partition function for these models and study the high temperature (low density) case of the corresponding gases for $N=2$. We show that quantum group gases exhibit anyonic behavior in $D=2

M. V. Manias, C. M. Naon, M. L. Trobo

We consider a recently proposed approach to bosonization in which the original fermionic partition function is expressed as a product of a $G/G$-coset model and a bosonic piece that contains the dynamics. In particular we show how the method works when topological backgrounds are taken into account. We also discuss the application of this technique to the ca

Kwan-Leung Chan

We investigate the effect of a constant threshold correction to a general non-extreme, static, spherically symmetric, electrically charged black hole solution of the dilatonic Einstein-Maxwell Lagrangian, with an arbitrary coupling $β$ between the electromagnetic tensor and the dilaton field. For a small $β$, an exact analytical solution is obtained. For an

Justin R. David, Avinash Dhar, Gautam Mandal, Spenta R. Wadia

We analyze terms subleading to Rutherford in the $S$-matrix between black hole and probes of successively high energies. We show that by an appropriate choice of the probe one can read off the quantum state of the black hole from the S-matrix, staying asymptotically far from the BH all the time. We interpret the scattering experiment as scattering off classi

H. Partouche

We review here some of the checks of string-string duality between N=2, D=4 Heterotic and Type II models. The heterotic low energy field theory is reproduced on the type II side. It is also shown to be a generalization in the string context of the rigid $N=2$ Yang-Mills theory of Seiberg and Witten which is exactly known. The non perturbative information of

J. -G. Zhou, J. -Q. Liang, J. Burzlaff, H. J. W. Mueller-Kirsten

Quantum tunneling between degenerate ground states through the central barrier of a potential is extended to excited states with the instanton method. This extension is achieved with the help of an LSZ reduction technique as in field theory and may be of importance in the study of macroscopic quantum phenomena in magnetic systems.

Carlos E. Laciana

Taking into account a neutral massive scalar field minimally coupled to gravity, in a Robertson-Walker metric, it is shown that when the final state is connected with the initial one by means of a Bogoliubov transformation, which does not include the single-mode rotation operator, the mean value of created particles is conserved. When the rotation operator i

Carlos E. Laciana

A generalization of ``Termo Field Dynamics'' to a curved geometry is proposed. In particular a neutral scalar field minimally coupled to gravity is considered as matter content in a Robertson-Walker metric. A non linear amplification in the particle creation is obtained, due to the altogether action of thermal and geometric effects. As a consequence

Carlos E. Laciana

Scalar radiation, represented by a massless scalar field in a Robertson-Walker metric, is taken into account. By using a weak non minimum vacuum definition, the radiation temperature as a time dependent function is obtained. When the universe evolution is nearly but non equal to $t^{1/2}$, it is possible to fit the temperature of the microwave background. A

Robert Coquereaux

We describe a few properties of the non semi-simple associative algebra H = M_3 + (M_{2|1}(Lambda2))_0, where Lambda2 is the Grassmann algebra with two generators. We show that H is not only a finite dimensional algebra but also a (non co-commutative) Hopf algebra, hence a finite dimensional quantum group. By selecting a system of explicit generators, we sho

Richard Battye, Paul Sutcliffe

We exhibit the dynamical scattering of multi-solitons in the Skyrme model for configurations with charge two, three and four. First, we construct maximally attractive configurations from a simple profile function and the product ansatz. Then using a sophisticated numerical algorithm, initially well-separated skyrmions in approximately symmetric configuration

Miguel S. Costa, Malcolm J. Perry

We present a class of Kaluza-Klein electrically charged black p-brane solutions of ten-dimensional, type IIA superstring theory. Uplifting to eleven dimensions these solutions are studied in the context of M-theory. They can be interpreted either as a p+1 extended object trapped around the eleventh dimension along which momentum is flowing or as a boost of t

Kurt Lechner, Mario Tonin

The quantum consistency of sigma-models describing the dynamics of extended objects in a curved background requires the cancellation of their world-volume anomalies, which are conformal anomalies for the heterotic string and $SO(1,5)$ Lorentz-anomalies for the heterotic five-brane, and of their ten dimensional target space anomalies. In determining these ano

Christopher D. Carone, Hitoshi Murayama

Horizontal flavor symmetries can drastically suppress Dirac neutrino masses well below those of the corresponding charged leptons. We show that models can be constructed where the light neutrino mass eigenvalues are small enough to give the MSW solution to the solar neutrino problem, with a right-handed neutrino scale no larger than a TeV. We present a model

Kingman Cheung, Robert M. Harris

We summarize results of the 1996 Snowmass workshop on future prospects for discovering dynamical electroweak symmetry breaking, compositeness, and anomalous couplings of quarks at colliders. We present the mass reach of the Tevatron to a color singlet or octet technirho, and to a topgluon or topcolor Z' from topcolor assisted technicolor. We explore the sens

J. D. Bjorken

A small test/experiment has been performed at the Fermilab Collider to measure charged particle and photon multiplicities in the forward direction, $η\approx 4.1$. The primary goal is to search for disoriented chiral condensate (DCC). The experiment and analysis methods are described, and preliminary results of the DCC search are presented.

P. Taxil, J. -M. Virey

A new handed interaction between quarks could be at the origin of some small parity violating effects in the inclusive production of one-jet in polarized $pp$ collisions. This interaction could originate from compositeness or from the presence of a new massive vector boson. The measurement of such asymmetries could be performed within a few years by using th

R. Casalbuoni, S. De Curtis, D. Guetta

In this paper we do an analysis of the reaction $e^+e^-\to W^+W^-$ for various options of the Next Linear Colliders (NLC), by considering the possibility of deviations from the Standard Model induced by anomalous trilinear vector boson couplings and non-standard fermionic couplings. We show that there are strong correlations among these parameters. By studyi

William B. Kilgore

Using a multi-channel analysis of W_L W_L scattering signals, I study the LHC's ability to distinguish among various models of strongly interacting electroweak symmetry breaking sectors.

Mar Bastero-Gil, Biswajoy Brahmachari

Following the suggestion of Bachas, Fabre and Yanagida (BFY), we analyze the gauge coupling unification at the two-loop order, in a supersymmetric scenario where scalars belonging to the adjoint representations contribute to the evolution of the couplings from intermediate scales onward, and the unification scale is pushed towards the string scale. Thereafte

Saumen Datta, Rajiv V. Gavai

Using improved mean field and strong coupling expansions we re-analyse the bulk phase diagram of the fundamental-adjoint action of the SU(2) Lattice Gauge Theory. We find that the qualitative features of the bulk phase diagram are robust and unchanged by the inclusion of higher order terms. On the other hand, some of the quantitative features, such as the lo

Gustavo Mana, Andrea Pelissetto, Alan D. Sokal

We carry out a high-precision simulation of the two-dimensional $SU(3)$ principal chiral model at correlation lengths $ξ$ up to $\sim 4 \times 10^5$, using a multi-grid Monte Carlo (MGMC) algorithm and approximately one year of Cray C-90 CPU time. We extrapolate the finite-volume Monte Carlo data to infinite volume using finite-size-scaling theory, and we di

G. Dautcourt

The theory obtained as a singular limit of General Relativity, if the reciprocal velocity of light is assumed to tend to zero, is known to be not exactly the Newton-Cartan theory, but a slight extension of this theory. It involves not only a Coriolis force field, which is natural in this theory (although not original Newtonian), but also a scalar field which

Nils Andersson, Kostas D. Kokkotas

We present new results for pulsating stars in general relativity. First we show that the so-called gravitational-wave modes of a neutron star can be excited when a gravitational wave impinges on the star. Numerical simulations suggest that the modes may be astrophysically relevant, and we discuss whether they will be observable with future gravitational-wave

R. Beig, P. T. Chruściel

We give a complete classification of all connected isometry groups, together with their actions in the asymptotic region, in asymptotically flat, asymptotically vacuum space--times with timelike ADM four--momentum.

M. Tsuda, T. Shirafuji

We study the structure of linearized field equations in $N = 1$ chiral supergravity (SUGRA) with a complex tetrad, as a preliminary to introducing additional auxiliary fields in order that the supersymmetry (SUSY) algebra close off shell. We follow the first-order formulation we have recently constructed using the method of the usual $N = 1$ SUGRA. In partic

Tamotsu Teruya

Let $N \subset M$ be an irreducible inclusion of type type II$_1$ factors with finite Jones index. We shall introduce the notion of normality for intermediate subfactors of the inclusion $N \subset M$. If the depth of $N \subset M$ is 2, then an intermediate subfactor $K$ for $N \subset M$ is normal in $ N \subset M$ if and only if the depths of $N \subset K

Sam Evens, Jiang-Hua Lu, Alan Weinstein

We show that every Lie algebroid $A$ over a manifold $P$ has a natural representation on the line bundle $Q_A = \wedge^{top}A \otimes \wedge^{top} T^*P$. The line bundle $Q_A$ may be viewed as the Lie algebroid analog of the orientation bundle in topology, and sections of $Q_A$ may be viewed as transverse measures to $A$. As a consequence, there is a well-de

P. Wiegmann

We discuss an interrelation between quantum integrable models and classical soliton equations with discretized time. It appeared that spectral characteristics of quantum integrable systems may be obtained from entirely classical set up. Namely, the eigenvalues of the quantum transfer matrix and the scattering $S$-matrix itself are identified with a certain $

Vincenzo Fiorentini, Michael Methfessel, Sabrina Oppo

Core-level shifts and core-hole screening effects in alloy formation are studied ``ab initio'' by constrained-density-functional total-energy calculations. For our case study, the ordered intermetallic alloy MgAu, final-state effects are essential to account for the experimental Mg 1s shift, while they are negligible for Au 4f. We explain the differe

J. Fricke, V. Meden, C. Wohler, K. Schonhammer

We study transport equations for quantum many-particle systems in terms of correlations by applying the general formalism developed in an earlier paper to exactly soluble electron-phonon models. The one-dimensional models considered are the polaron model with a linear energy dispersion for the electrons and a finite number of electrons and the same model inc

J. Fricke

We present a new method to derive transport equations for quantum many-particle systems. This method uses an equation-of-motion technique and is applicable to systems with bosons and fermions, arbitrary interactions and time-dependent external fields. Using a cluster expansion of the r-particle density matrices the infinite hierarchy of equations of motion f

T. Fukui, N. Kawakami

The SU($ν$) generalized Haldane-Shastry spin chain with $1/r^2$ interaction is studied with twisted boundary conditions. The exact wavefunctions of Jastrow type are obtained for every rational value of the twist angle in unit of $2π$. The spectral flow of the ground state is then discussed as a function of the twist angle. By resorting to the motif picture i

R. Mettin

It is demonstrated that improved entrainment control of chaotic systems can maintain periodic goal dynamics near unstable periodic orbits without feedback. The method is based on the optimization of goal trajectories and leads to small open-loop control forces.

S. Zaroubi, N. Sugiyama, J. Silk, Y. Hoffman

The mass density field as extracted from peculiar velocities in our cosmological neighborhood is mapped back in time to the CMB in two ways. First, the density power spectrum ($P_k$) is translated into a temperature angular power spectrum of sub-degree resolution ($C_l$) and compared to observations. Second, the local density field is translated into a tempe

Robert Popham

We examine various ways in which disk accretion can heat an accreting star. These include 1) radiation emitted from the disk surface which is intercepted by the stellar surface, 2) radiative flux directly across the disk-star interface, and 3) advection of thermal energy from the disk into the star. For each of these, the physics of the boundary layer betwee

Riccardo Giovanelli, Martha P. Haynes, Gary Wegner, Luiz N. da Costa

We use Tully--Fisher distances for a sample of field late spiral galaxies to test the Lauer and Postman (1994; hereinafter LP) result suggestive of a bulk flow with respect to the Cosmic Microwave Background reference frame, of amplitude of +689 km/s in the direction l=343, b=+52. A total of 432 galaxies are used, subdivided between two cones, of 30deg semia

Riccardo Giovanelli

Reviews observational situation in the measurement of peculiar velocities in the local universe. Emphasis is placed on such topics as: Do spirals and ellipticals yield the same peculiar velocity field? What is the cluster velocity distribution function? What is the convergence depth of the local universe, as seen by inspection of motions of clusters and of f

The PLANET Collaboration, M. Albrow, J. -P. Beaulieu, P. Birch

The Probing Lensing Anomalies NETwork (PLANET) is a worldwide collaboration of astronomers using semi-dedicated European, South African, and Australian telescopes to perform continuous, rapid and precise multi-band CCD photometric monitoring of on-going Galactic microlensing events. As well as providing important additional information on the nature, distrib

C. S. Reynolds

I present a study of the X-ray spectral properties of a sample containing 24 type-1 active galactic nuclei using the medium spectral resolution of ``ASCA''. The sample consists of 20 radio-quiet objects and 4 radio-loud objects. A simple power-law continuum absorbed by Galactic material provides a very poor description of the spectra of most objects.

James G. Bartlett, Daniel Egret

We discuss some aspects of data management important to cross-wavelength comparison of images and catalogs. We then consider the application of statistics to the general problem of object cross-identification. Finally, two software systems developed as tools to aid the comparison of catalogs and images are briefly presented.

Alexander Vilenkin

A (very) brief review of topological defects and their possible cosmic roles. I emphasize in particular that superheavy defects needed for structure formation can peacefully coexist with inflation, despite the claims to the contrary which are often made in the literature.

L. R. Jones, I. M. McHardy, M. R. Merrifield, K. O. Mason

In the deepest optically identified X-ray survey yet performed, we have identified 32 X-ray selected QSOs to a flux limit of 2x10^{-15} erg cm^{-2} s^{-1} (0.5-2 keV). The survey, performed with the ROSAT PSPC, has 89% spectroscopic completeness. The QSO log(N)-log(S) relation is found to have a break to a flat slope at faint fluxes. The surface density of Q

B. Scott Gaudi, Andrew Gould

A planetary microlensing event occurs when a planet perturbs one of the two images created in a point-mass microlensing event, causing a deviation from the standard Paczyński curve. Determination of the two physical parameters that can be extracted from a planetary microlensing event, the planet/star mass ratio q, and the planet/star separation in units of t

Wolfgang Brandner, Hans Zinnecker

We have analyzed photometric and spectroscopic data of a sample of 14 spatially resolved pre-main-sequence binaries (separations 0.6" to 1.7") in the nearby (150 pc) low-mass star-forming regions of Chamaeleon, Lupus, and rho Ophiuchi. The spectroscopic data have been obtained with the ESO New Technology Telescope (NTT) at La Silla under subarcsec se

T. Nakamura, Y. Kan-ya, R. Nishi

If the density distribution ρ(r) of MACHOs is spherically symmetric with respect to the Galactic center, it is shown that the minimal total mass M_{min}^{ MACHO} of the MACHOs is 1.7\times 10^{10}\sol τ_{-6.7}^{ LMC} where τ_{-6.7}^{ LMC} is the optical depth (τ^{ LMC}) toward the Large Magellanic Cloud (LMC) in the unit of 2\times 10^{-7}. If ρ(r) is a decr

Nick Kaiser

We explore the dependence of weak lensing phenomena on the background cosmology. We first generalise the relation between $P_ψ(ω)$, the angular power spectrum of the distortion, and the power spectrum of density fluctuations to non-flat cosmologies. We then compute $P_ψ$ for various illustrative models. A useful cosmological discriminator is the growth of $P

Sanjay Reddy, Madappa Prakash

We calculate neutrino cross sections from neutral current reactions in the dense matter encountered in the evolution of a newly born neutron star. Effects of composition and of strong interactions in the deleptonization and cooling phases of the evolution are studied. The influence of the possible presence of strangeness-rich hyperons on the neutrino scatter

W. Ogawaguchi, Y. Kojima

We have calculated evolution of neutron star binaries towards the coalescence driven by gravitational radiation. The hydrodynamical effects as well as the general relativistic effects are important in the final phase. All corrections up to post$^{2.5}$-Newtonian order and the tidal effect are included in the orbital motion. The star is approximated by a simp

Zurab Kakushadze, S. -H. Henry Tye

We give a classification of 3-family SO(10) and E_6 grand unification in string theory within the framework of conformal field theory and asymmetric orbifolds. We argue that the construction of such models in the heterotic string theory requires certain Z_6 asymmetric orbifolds that include a Z_3 outer-automorphism, the latter yielding a level-3 current alge

F. Evers, D. Belitz, Wansoo Park

The expansion of the conductivity in 2-d quantum Lorentz models in terms of the scatterer density n is considered. We show that nonanalyticities in the density expansion due to scattering processes with small and large momentum transfers, respectively, have different functional forms. Some of the latter are not logarithmic, but rather of power-law nature, in

I. Vekhter, A. Houghton

The Hall conductivity in the mixed state of a clean ($l \gg ξ_0$) type-II s-wave superconductor is determined from a microscopic calculation within a quasiclassical approximation. We find that below the superconducting transition the contribution to the transverse conductivity due to dynamical fluctuations of the order parameter is compensated by the modific

G. Date

Einstein equations with $T_{μν} = k_μk_ν+ \ell_μ\ell_ν$ where $k, \ell$ are null are considered with spherical symmetry and staticity. The solution has naked singularity and is not asymptotically flat. However, it may be interpreted as an envelope for any static spherical body making it more massive. Such an interpretation and some of its implications are de

E. J. Beggs, P. R. Johnson

We implement the inverse scattering method in the case of the $A_n$ affine Toda field theories, by studying the space-time evolution of simple poles in the underlying loop group. We find the known single soliton solutions, as well as additional solutions with non-linear modes of oscillation around the standard solution, by studying the particularly simple ca

D. de Florian, R. Sassot

We calculate next to leading order QCD corrections to semi-inclusive polarized deep inelastic scattering and $e^+e^-$ annihilation cross sections for processes where the polarization of the identified final-state hadron can also be determined. Using dimensional regularization and the HVBM prescription for the $γ_5$ matrix, we compute corrections for differen

A. Feinstein, M. A. Pérez Sebastián

We discuss the entropy generation in quantum tunneling of a relativistic particle under the influence of a time varying force with the help of squeezing formalism. It is shown that if one associates classical coarse grained entropy to the phase space volume, there is an inevitable entropy increase due to the changes in position and momentum variances. The en

M. E. Madjet, P. A. Hervieux, D. H. E. Gross, O. Schapiro

We present a statistical fragmentation study of doubly charged alkali (Li, Na, K) and antimony clusters. The evaporation of one charged trimer is the most dominant decay channel (asymmetric fission) at low excitation energies. For small sodium clusters this was quite early found in molecular dynamical calculations by Landman et al. For doubly charged lithium

Johan Bijnens, Joaquim Prades

The unknown constants in Chiral Perturbation Theory needed for an all orders analysis of the polarizabilities and electromagnetic corrections to the masses of the pseudo-Goldstone bosons are estimated at leading order in $1/N_c$. We organize the calculation in an $1/N_c$-expansion and separate long- and short-distance physics contributions by introducing an

Shin Ishida, Taku Ishida, Muneyuki Ishida, Kunio Takamatsu

In a previous work, we have reanalyzed the I=0 S-wave ππ-scattering phase-shift through a new method of Interfering Breit-Wigner amplitudes, and have shown the existence of a light scalar, σparticle, accompanied by a negative "repulsive core"-type background phase-shift, whose origin may have some correspondence to a ``compensating'' ππcontac

B. K. Darian, H. P. Kunzle

We use a systematic construction method for invariant connections on homogeneous spaces to find the Einstein-SU(n)-Yang-Mills equations for Friedmann-Robertson-Walker and locally rotationally symmetric homogeneous cosmologies. These connections depend on the choice of a homomorphism from the isotropy group into the gauge group. We consider here the cases of

Sergey Arkhipov

It is known that the semi-infinite cohomology spaces of the infinitely twisted nilpotent subalgebra in an affine Lie algebra $g$ with coefficients in an integrable simple module over the affine Lie algebra have a base enumerated by elements of the corresponding affine Weyl group graded by the semiinfinite length function. Let $U$ be the affine quantum group

Karol Przanowski

The infinitesimal form of the induced representation of the kappa-Poincare group is constructed. The infinitesimal action of the kappa-Poincare group on the kappa-Minkowski space is described. The actions of these two infinitesimal forms on the solution of Klein-Gordon equation are compared.

Katsuhisa Mimachi

We give a short proof of the inner product conjecture for the symmetric Macdonald polynomials of type $A_{n-1}$. As a special case, the corresponding constant term conjecture is also proved.

Friedrich Knop, Siddhartha Sahi

In this paper, we introduce a new family of symmetric polynomials which depends on a parameter r. They are defined by specifying certain of their zeros. For the parameter values 1/2, 1, and 2 they have an interpretation in terms of Capelli identities. First, we give explicit formulas in some special cases. Then we show that the polynomials can also be define

Friedrich Knop, Siddhartha Sahi

Heckman and Opdam introduced a non-symmetric analogue of Jack polynomials using Cherednik operators. In this paper, we derive a simple recursion formula for these polynomials and formulas relating the symmetric Jack polynomials with the non-symmetric ones. These formulas are then implemented by a closed expression of symmetric and non-symmetric Jack polynomi

Jian-yu Lu, J. F. Greenleaf, Erasmo Recami

We have developed a new family of limited-diffraction electromagnetic X-shaped waves based on the scalar "X waves" discovered previously. These waves are diffraction-free in theory and particle-like (wave packets), in that they maintain their shape as they propagate to an infinite distance. The X waves possess (theoretically) infinitely extended arms

Samar Abbas

Recent advances in interdisciplinary fields as diverse as astrophysics, cosmogeophysics, nuclear geology, etc. have led to interesting developments in the non-organic theory of the genesis of petroleum. This theory, which holds that petroleum is of an abiogenic primordial origin, provides an explanation for certain features of petroleum geology that are hard