November 2001 arXiv papers — page 8

Adam Dobrzycki, Jill Bechtold, Jennifer Scott, Miwa Morita

We present results on the evolution and clustering of Ly-alpha lines at low z. The sample contains 1298 Ly-alpha lines from 165 quasar spectra mined from the archives of the HST/FOS. Our sample extends to z=1.7, slightly higher than the sample analyzed by the HST Quasar Absorption Line Key Project. We confirm the Key Project result that the number density ev

A. Kundu, B. C. Whitmore

We present the results of our detailed WFPC2-based photometric study of the globular cluster systems (GCS) of over 60 elliptical and S0 galaxies. Approximately 50\% of the GCSs of ellipticals, and at least 15-20\% of S0s reveal bimodality in the color distribution. We trace the variation in GCS properties with Hubble type and discuss the implications on the

Gianfranco De Zotti, Carlo Burigana, Carlo Baccigalupi

We present a tentative summary of the many very interesting issues that have been addresses at this workshop, focussing in particular on the perspectives for measuring the polarization power spectra of the Cosmic Microwave Background produced by scalar and tensor perturbations, in the presence of foregrounds.

John F. Beacom, Patrick Crotty, Edward W. Kolb

Earth absorbs $\nue$ and $\numu$ of energies above about 100 TeV. As is well-known, although $\nutau$ will also disappear through charged-current interactions, the $\nutau$ flux will be regenerated by prompt tau decays. We show that this process also produces relatively large fluxes of secondary $\nube$ and $\nubmu$, greatly enhancing the detectability of th

Jonathan P. Williams, Catherine A. Garland

Observations of the dust and gas toward two young stellar clusters, IRS1 and IRS2, in the NGC2264 star forming region are presented. Continuum emission is used to locate the dusty envelopes around the clusters and individual protostars within and line emission from the J=3-2 transitions of HCO+ and H13CO+ is used to diagnose the gas flows around them. The mo

L. Baldini, L. Brocco, D. Casadei, F. Cindolo

The Time-of-Flight (TOF) system of the AMS detector gives the fast trigger to the read out electronics and measures velocity, direction and charge of the crossing particles. The first version of the detector (called AMS-01) has flown in 1998 aboard of the shuttle Discovery for a 10 days test mission, and collected about $10^8$ events. The new version (called

J. C. Niemeyer

It is shown that varying speed of light cosmology follows from a string-inspired minimal length uncertainty relation. Due to the reduction of the available phase space volume per quantum mode at short wavelengths, the equation of state of ultrarelativistic particles stiffens at very high densities. This causes a stronger than usual deceleration of the scale

Peter Teuben, Dave DeYoung, Piet Hut, Stuart Levy

During the last couple of years, observers have started to make plans for a Virtual Observatory, as a federation of existing data bases, connected through levels of software that enable rapid searches, correlations, and various forms of data mining. We propose to extend the notion of a Virtual Observatory by adding archives of simulations, together with inte

R. I. Hynes

We describe an algorithm to optimally extract individual spectra of blended sources from a long slit spectrum. A semi-analytic model for the spatial profile is used: a Voigt profile for the undersampled core with a numerical correction applied to the wings. This is derived from an isolated source which must also be placed on the slit. Chi^2 fitting is used t

Jos de Bruijne, Alastair Reynolds, Michael Perryman, Anthony Peacock

We present observations of 11 quasars, selected in the range z = 2.2-4.1, obtained with ESA's Superconducting Tunnel Junction (STJ) camera on the WHT. Using a single template quasar spectrum, we show that we can determine the redshifts of these objects to about 1%. A follow-up spectroscopic observation of one QSO for which our best-fit redshift (z = 2.97

M. Reinecke, W. Hillebrandt, J. C. Niemeyer

Following up on earlier work on this topic (Reinecke et al. 1999, A&A 347, pp. 724 and 739), we present an improved set of numerical models for simulations of white dwarfs exploding as Type Ia supernovae (SNe Ia). Two-dimensional simulations were used to test the reliability and numerical robustness of these algorithms; the results indicate that integral qua

Janusz A. Gil, George I. Melikidze, Dipanjan Mitra

We propose a vacuum gap (VG) model which can be applied uniformly for normal and high magnetic field pulsars. The model requires strong and non-dipolar surface magnetic field near the pulsar polar cap. We assume that the actual surface magnetic field in pulsars results from a superposition of global dipole field and crust-anchored small scale magnetic anomal

M. Reinecke, J. C. Niemeyer, W. Hillebrandt

In this article we discuss the first simulations of two- and three-dimensional Type Ia supernovae with an improved hydrodynamics code. After describing the various enhancements, the obtained results are compared to those of earlier code versions, observational data and the findings of other researchers in this field.

E. C. Moran, M. Eracleous, K. M. Leighly, G. Chartas

We present the results of a 17 ks Chandra observation of the nearby dwarf spiral galaxy NGC 4395, focusing on the X-ray properties of the moderate-mass black hole that resides in its nucleus. Chandra affords the first high-quality, broadband X-ray detection of this object that is free of contamination from nearby sources in the field. We find that the nuclea

V. Reshetnikov, E. Battaner, F. Combes, J. Jimenez-Vicente

We present a statistical study of the presence of galaxy warps in the Hubble deep fields. Among a complete sample of 45 edge-on galaxies above a diameter of 1.''3, we find 5 galaxies to be certainly warped and 6 galaxies as good candidates. In addition, 4 galaxies reveal a characteristic U-warp. Compared to statistical studies of local warps, and tak

Z. Papadopolos, G. Kasner, J. Ledieu, E. J. Cox

The structure of the Al_{70}Pd_{21}Mn_{9} surface has been investigated using high resolution scanning tunnelling microscopy (STM). From two large five-fold terraces on the surface in a short decorated Fibonacci sequence, atomically resolved surface images have been obtained. One of these terraces carries a rare local configuration in a form of a ring. The l

George B. Field, Eric G. Blackman

We present a two-scale approximation for the dynamics of a nonlinear $α^2$ dynamo. Solutions of the resulting nonlinear equations agree with the numerical simulations of Brandenburg (2001), and show that $α$ is quenched by the buildup of magnetic helicity at the forcing scale $1/k_2$ as the $α$ effect transfers it from the large scale $1/k_1$. For times $t >

Kristen Menou

Recent work on the modes of accretion onto black holes (BHs) in Soft X-Ray Transients (SXTs) is reviewed, with an emphasis on uncertainties affecting models of accretion during quiescence (inner hot flow, outer thin disk). Various interpretations of the quiescent X-ray luminosity difference between systems containing neutron stars (NSs) and systems containin

Michael Flohr

These are notes of my lectures held at the first School & Workshop on Logarithmic Conformal Field Theory and its Applications, September 2001 in Tehran, Iran. These notes cover only selected parts of the by now quite extensive knowledge on logarithmic conformal field theories. In particular, I discuss the proper generalization of null vectors towards the log

Ji-Feng Yang

We illustrated via the sunset diagram that dimensional regularization 'deforms' the nonlocal contents of multi-loop diagrams with its equivalence to cut-off regularization scheme recovered only after sub-divergence were subtracted. Then we employed a differential equation approach for calculating loop diagrams to verify that dimensional regularizatio

A. A. Sen, S. Sethi

We have reinvestigated the quintessence model with minimally coupled scalar field in the context of recent Supernova observation at $z=1.7$. By assuming the form of the scale factor which gives both the early time deceleration and late time acceleration, consistent with the observations, we show that one needs a double exponential potential. We have also sho

Michael R. Santos, Volker Bromm, Marc Kamionkowski

We calculate the contribution to the cosmic infrared background from very massive metal-free stars at high redshift. We explore two plausible star-formation models and two limiting cases for the reprocessing of the ionizing stellar emission. We find that Population III stars may contribute significantly to the cosmic near-infrared background if the following

Kathryn V. Johnston, Philip I. Choi, Puragra Guhathakurta

Recent observations of surface brightness distributions of both Milky Way and M31 satellite galaxies have revealed many instances of sudden changes or breaks in the slope of the surface brightness profiles (at some break radius, r_break). These breaks are often accompanied by increasingly elliptical isophotes and sometimes by isophote twisting. We investigat

Philip I. Choi, Puragra Guhathakurta, Kathryn V. Johnston

We investigate the interaction history of the M31 sub-group of galaxies by comparing surface photometry of its two nearest satellites, M32 and NGC 205, with N-body simulations of satellite destruction. The recent discovery of a giant stream in M31's outer halo, apparently pointed towards M32 and NGC 205, makes such an investigation particularly relevant.

Mu-in Park

From first principles, I present a concrete realization of Carlip's idea on the black hole entropy from the conformal field theory on the horizon in any dimension. New formulation is free of inconsistencies encountered in Carlip's. By considering a correct gravity action, whose variational principle is well defined at the horizon, I $derive$ a correc

Wojciech H. Zurek

The aim of these lectures is to investigate the transfer of information occurring in course of quantum interactions. In particular, I shall explore circumstances in which such an information transfer with the quantum environment of the considered quantum system leads to the destruction of the phase coherence between the states of the privileged basis in the

Sibasish Ghosh, Guruprasad Kar, Anirban Roy, Debasis Sarkar

We show that the four states a|00>+b|11>, b^*|00>-a^*|11>, c|01>+d|10> and d^*|01>-c^*|10> cannot be discriminated with certainty if only local operations and classical communication (LOCC) are allowed and if only a single copy is provided, except in the case when they are simply |00>, |11>, |01> and |10> (in which case they are trivially distinguishable wit

W. Q. Chao, C. S. Ju

The newly developed single trajectory quadrature method is applied to a two-dimensional example. The results based on different versions of new perturbation expansion and the new Green's function deduced from this method are compared to each other, also compared to the result from the traditional perturbation theory. As the first application to higher-di

Janusz Skalski

Imaginary- and real-time versions of an equation for the condensate density are presented which describe dynamics and decay of any spherical Bose-Einstein condensate (BEC) within the mean field appraoch. We obtain quantized energies of collective finite amplitude radial oscillations and exact numerical instanton solutions which describe quantum tunneling fro

G. Leveque, G. Colas des Francs, C. Girard, J. -C. Weeber

The polarization state of the optical electromagnetic field lying several nanometers above complex dielectric structures reveals the intricate light-matter interaction that occurs in this near-field zone. This information can only be extracted from an analysis of the polarization state of the detected light in the near-field. These polarization states can be

V. V. Lyahov, V. M. Neshchadim

Within the framework of the hypothesis offered by authors about complex-valued nature of physical quantities, the effect of the Landau damping has been explored with assumption that not only frequency can be a small imaginary component but also a wave vector. The numerical solution of the obtained dispersion equation testifies that uncollisional damping is a

R. Bakker, T. Birke, R. Mueller

The first two years of user service of the third generation light source BESSY II emphasized the importance of a reliable, comprehensive and dense logging of a few thousand setpoints, readbacks, status and alarm values. Today data from sources with various characteristics residing in different protected networks are centrally collected and retrievable via an

Janusz Skalski

We examine a recently proposed nucleon-nucleon interaction, claimed by its authors both realistic and leading to a standing wave instability in symmetric nuclear matter. Contrary to these claims, we find that this interaction leads to a serious overbinding of 4He, 16O and 40Ca nuclei when the Hartree-Fock method is properly applied. The resulting nuclear den

I. R. Gabitov, P. M. Lushnikov

We propose using a nonlinear phase shift interferometric converter (NPSIC) (a new device) for lumped compensation of the nonlinearity in optical fibers. The NPSIC is a nonlinear analog of the Mach-Zehnder interferometer and provides a way to control the sign of the nonlinear phase shift. We investigate a potential use of NPSIC for compensation of the nonline

J. F. Vazquez-Poritz

All previous Randall-Sundrum type models have required a Z_2 identification source which does not have a known string theoretic origin. We show that the near-horizon of various resolved branes on an Eguchi-Hanson instanton dimensionally reduce to a five-dimensional domain wall that traps gravity, without an additional delta-function source. This brings us su

Robert Bluhm

Experiments in atomic physics have exceptional sensitivity to small shifts in energy in an atom, ion, or bound particle. They are particularly well suited to search for unique low-energy signatures of new physics, including effects that could originate from the Planck scale. A number of recent experiments have used CPT and Lorentz violation as a candidate si

Pietro Faccioli

We propose a non-perturbative calculation scheme which is based on the semi-classical approximation of QCD and can be used to evaluate quantities of interest in hadronic physics. As a first application, we evaluate the mass of the pion and of the nucleon. Such masses are related to a particular combination of Green functions which, in some limit, is dominate

Y. F. Wang, K. Whisnant, Z. Xiong, Jin Min Yang

We examine the prospects of making a joint analysis of neutrino oscillation at two baselines with neutrino superbeams. Assuming narrow band superbeams and a 100 kt water Cerenkov calorimeter, we calculate the event rates and sensitivities to the matter effect, the signs of the neutrino mass differences, the CP phase and the mixing angle θ_{13}. Taking into a

W. A. Hofer, A. J. Fisher

The spin-polarized scanning tunnelling microscope (STM) can in principle resolve not only the electronic, but also the magnetic surface structure. We model recent STM measurements achieving magnetic resolution on the atomic scale by a first-principles method. It is shown that the signature of a specific magnetic or non-magnetic STM tip can unambiguously be i

George M. Chechin, Alexandr V. Gnezdilov, Vladimir P. Sakhnenko, Mikhail Yu. Zekhtser

Bushes of normal modes represent exact mathematical objects describing specific dynamical regimes in nonlinear mechanical systems with point or space symmetry. In the present paper, we outline the bush theory and illustrate it with some bushes of small dimensions in octahedral mechanical structures.

Shlomo Dado, Arnon Dar, Alvaro De Rujula

In order to assist in planing the search of supernova (SN) in the late time afterglow (AG) of the gamma ray burst (GRB) 011121 we use the Cannonball Model of GRBs and the observations of its afterglow in the R band in the first two days to predict its late time decline and intrinsic spectrum.

Marco Frasca

A two-level atom interacting with a single radiation mode is considered, without the rotating-wave approximation, in the strong coupling regime. It is shown that, in agreement with the recent results on Rabi oscillations in a Josephson junction (Y. Nakamura, Yu. A. Pashkin and J. S. Tsai, Phys. Rev. Lett. {\bf 87}, 246601 (2001)), the Rabi frequency is indee

M. Glueck, A. R. Kolovsky, H. J. Korsch

In this work, we discuss the resonance states of a quantum particle in a periodic potential plus a static force. Originally this problem was formulated for a crystal electron subject to a static electric field and it is nowadays known as the Wannier-Stark problem. We describe a novel approach to the Wannier-Stark problem developed in recent years. This appro

Neil Russell

Space-based clock-comparison experiments can provide Planck-scale sensitivity to many parameters for Lorentz and CPT violation that are difficult to measure on Earth. The principal advantages are a reduced timescale for data collection, reduced suppression for certain effects, and access to certain parameters not possible with Earth-based experiments.

L. Pietronero, M. Bottaccio, M. Montuori, F. Sylos Labini

The study of the properties of cosmic structures in the universe is one of the most fascinating subject of the modern cosmology research. Far from being predicted, the large scale structure of the matter distribution is a very recent discovery, which continuosly exhibits new features and issues. We have faced such topic along two directions; from one side we

Remi Carles

Bose-Einstein condensation is usually modeled by nonlinear Schroedinger equations with harmonic potential. We study the Cauchy problem for these equations. We show that the local problem can be treated as in the case with no potential. For the global problem, we establish an evolution law, which is the analogue of the pseudo-conformal conservation law for th

E. O. Iltan

We study the flavor changing t -> c H^0 decay in the framework of the general two Higgs doublet model, so called model III. Here, we take the Yukawa couplings complex and switch on the CP violating effects. We predict the branching ratio six orders larger compared to the one calculated in the SM, namely BR ~ 10^{-7}, and observe a measurable CP asymmetry, at

Toshiki Ide, Holger F. Hofmann, Akira Furusawa, Takayoshi Kobayashi

The fidelity of continuous variable teleportation can be optimized by changing the gain in the modulation of the output field. We discuss the gain dependence of fidelity for coherent, vacuum and one photon inputs and propose optimal gain tuning strategies for corresponding input selections.

Yukio Yasui, Masaki Kanada, Masafumi Ito, Hiroshi Harashina

Static and dynamical properties of the magnetic moment system of pyrochlore compound Tb2Ti2O7 with strong magnetic frustration, have been investigated down to the temperature T=0.4 K by neutron scattering on a single crystal sample. The scattering vector (Q)-dependence of the magnetic scattering intensity becomes appreciable with decreasing T at around 30 K,

D. D'Alessandro

Consider a compact connected Lie group $G$ and the corresponding Lie algebra $\cal L$. Let $\{X_1,...,X_m\}$ be a set of generators for the Lie algebra $\cal L$. We prove that $G$ is uniformly finitely generated by $\{X_1,...,X_m\}$. This means that every element $K \in G$ can be expressed as $K=e^{Xt_1}e^{Xt_2} \cdot \cdot \cdot e^{Xt_l}$, where the indeter

W. A. Hofer

We present a theoretical model which allows to keep track of all photons in an interferometer. The model is implemented in a numerical scheme, and we simulate photon interference measurements on one, two, four, and eight slits. Measurements are simulated for the high intensity regime, where we show that our simulations describe all experimental results so fa

Andrei Khrennikov, Johann Summhammer

This dialogue took place at Växjö, 19 November 2001. The main aim of our meeting in Växjö was to clarify our viewpoints on foundations of quantum mechanics. The most attractive in our discussion was the extreme difference in our quantum experiences. On one side, pure mathematician (specializing in foundations of probability theory), Andrei Khrennikov; on the

Stefano Mancini, Rodolfo Bonifacio

We address the timing problem in realizing correcting codes for quantum information processing. To deal with temporal uncertainties we employ a consistent quantum mechanical approach. The conditions for optimizing the effect of error correction in such a case are determined.

Stefano Mancini, Vladimir I. Man'ko

We study the possibility of exploiting superpositions of coherent states to encode qubit. A comparison between the use of deformed and undeformed bosonic algebra is made in connection with the amplitude damping errors.

Timo Korhonen, Martin Heiniger

The timing system of the Swiss Light Source is based on the event system concept of APS, Argonne [1]. However, for SLS the hardware was completely redesigned while preserving the software compatibility with the APS system. This gave us a head start in the implementation: we could use the latest available hardware and take advantage of the features integrated

J. Krempasky, R. Krempaska, D. Vermeulen, D. Maden

On December 15th the Swiss Light Source (SLS) produced a stored beam for the first time. This important milestone was achieved in a very tight time schedule. The fact that all major systems are controlled by Epics made this challenge feasible. In the first phase there are four beamlines: two for the surface science community, one for powder and surface diffr

Reginald J. Hill

The variances of the fluid-particle acceleration and of the pressure-gradient and viscous force are given. The scaling parameters for these variances are velocity statistics measureable with a single-wire anemometer. For both high and low Reynolds numbers, asymptotic scaling formulas are given; these agree quantitatively with DNS data. Thus, the scaling can

R. D. Pisarski, D. H. Rischke

The gap parameter for color superconductivity is expected to be a gauge invariant quantity, at least on the appropriate mass shell. Computing the gap to subleading order in the QCD coupling constant, g, we show that the prefactor of the exponential in 1/g is gauge dependent off the mass shell, and independent of gauge on the mass shell.

Paul B. Slater

We find for the unitary evolution of spin-1/2 systems that the "purely mathematical mixed state holonomy of Uhlmann limitedly agrees, in the case of evolution over geodesic spherical triangles, with the holonomy "in the experimental context of quantum interferometry" recently proposed by Sjoqvist, Pati, Ekert, Anandan, Ericsson, Oi and Vedral (Ph

Raphael Yuster

The domatic number of a graph $G$, denoted $dom(G)$, is the maximum possible cardinality of a family of disjoint sets of vertices of $G$, each set being a dominating set of $G$. It is well known that every graph without isolated vertices has $dom(G) \geq 2$. For every $k$, it is known that there are graphs with minimum degree at least $k$ and with $dom(G)=2$

Bong H. Lian, Chien-Hao Liu, Kefeng Liu, Shing-Tung Yau

We describe the $S^1$-action on the Quot-scheme $\Quot({\cal E}^n)$ associated to the trivial bundle ${\cal E}^n=CP^1\times{\smallBbb C}^n$. In particlular, the topology of the $S^1$-fixed-point components in $\Quot({\cal E}^n)$ and the $S^1$-weights of the normal bundle of these components are worked out. Mirror Principle, as developed by three of the curre

Rolf Schimmrigk

It is proposed that certain techniques from arithmetic algebraic geometry provide a framework which is useful to formulate a direct and intrinsic link between the geometry of Calabi-Yau manifolds and the underlying conformal field theory. Specifically it is pointed out how the algebraic number field determined by the fusion rules of the conformal field theor

J. W. Moffat

A conjectured finite M-theory based on eleven-dimensional supergravity formulated in a superspace with a non-anticommutative <>-product of field operators is proposed. Supermembranes are incorporated in the superspace <>-product formalism. When the deformed supersymmetry invariant action of eleven-dimensional supergravity theory is expanded about the standar

Dmitri Antonov

The renormalization-group (RG) flow in the finite-temperature (2+1)-dimensional Georgi-Glashow model is explored. This is done in the limit when the squared electric coupling constant is much larger than the mass of the Higgs field. The novel equation describing the evolution of the Higgs mass is derived and integrated along the separatrices of the RG flow i

S. I. Kruglov

The Maxwell theory on non-commutative spaces has been considered. The non-linear equations of electromagnetic fields on non-commutative spaces were obtained in the compact spin-tensor (quaternion) form. It was shown that the plane electromagnetic wave is the solution of the system of non-linear wave equations of the second order for the electric and magnetic

Ji-Feng Yang

Formulating the QFT&#39;s as coarse grained &#39;low&#39; energy sectors of a postulated complete quantum theory of everything with the &#39;high&#39; energy modes integrated out or &#39;clustering&#39; into &#39;low&#39; energy objects, we can evaluate the Feynman amplitudes by solving a series of natural differential equations which automatically dissolves

N. Nimai Singh, Mahadev Patgiri

We study the origin of neutrino masses and mixing angles which can accomodate the LMA MSW solutions of the solar neutrino anomaly as well as the solution of the atmospheric neutrino problem, within the framework of the see-saw mechanism. We employ the diagonal form of the Dirac neutrino mass matrices with the physical masses as diagonal elements in the hiera

Chongxing Yue, Hong Li, Xuelei Wang

We calculate the contributions of the neutral top-pion $π_{t}^0$ to the process $e^-γ\to e^-\bar{t}c$ in the framework of topcolor-assisted technicolor(TC2) models and discuss the possible of detecting $π_t^0$ at the high energy linear $e^+e^-$ collider(LC). Our results show that $π_t^0$ can give significant contributions to this process. With reasonable val

Sheldon Stone

I discuss how b decays can be used to unravel new physics beyond the Standard Model. Decays second order in the weak interaction involving loops and CP violation are emphasized. This information is complementary to that obtainable with higher energy machines.

X. Liao, T. Manke

We report on a first relativistic calculation of the quenched bottomonium spectrum from anisotropic lattices. Using a very fine discretisation in the temporal direction we were able to go beyond the non-relativistic approximation and perform a continuum extrapolation of our results from five different lattice spacings (0.04-0.17 fm) and two anisotropies (4 a

L. Gladilin

Recent results on charm and beauty photoproduction at HERA are discussed. The perturbative QCD calculations are generally smaller than the measured cross sections, particularly in the forward (proton) direction. The study of charm dijet photoproduction is consistent with a significant contribution of charm excitation processes.

S. G. Ghosh, R. V. Saraykar

We study the occurrence of naked singularities in the spherically symmetric collapse of radiation shells in a higher dimensional spacetime. The necessary conditions for the formation of a naked singularity or a black hole are obtained. The naked singularities are found to be strong in the Tipler&#39;s sense and thus violating cosmic censorship conjecture.

Sameer Sapra, D. D. Sarma, S. Sanvito, N. A. Hill

We investigate the effect of quantum confinement on the ferromagnetism of diluted magnetic semiconductor Ga$_{1-x}$Mn$_x$As using a combination of tight-binding and density functional methods. We observe strong majority-spin Mn $d$-As $p$ hybridization, as well as half metallic behavior, down to sizes as small as 20 Åin diameter. Below this critical size, th

A. L. Chernyshev, Steven R. White, A. H. Castro Neto

With the help of analytical and numerical studies of the $t$-$J_z$ model we argue that the charge stripe in an antiferromagnetic insulator should be understood as a system of holon-spin-polaron excitations condensed at the self-induced antiphase domain wall. The structure of such a charge excitation is studied in detail with numerical and analytical results

A. L. Chernyshev, Y. C. Chen, A. H. Castro Neto

We have studied the static and dynamic properties of quasi-two-dimensional quantum antiferromagnets (AF) diluted with spinless impurities using spin-wave theory and $T$-matrix approximation. We show that the spectrum of a 2D AF at long wavelengths is overdamped at arbitrary concentration of spinless impurities. The scattering leads to a new length scale $\el

M. Bottaccio, L. Pietronero, A. Amici, P. Moicchi

Self-gravitating systems have acquired growing interest in statistical mechanics, due to the peculiarities of the 1/r potential. Indeed, the usual approach of statistical mechanics cannot be applied to a system of many point particles interacting with the Newtonian potential, because of (i) the long range nature of the 1/r potential and of (ii) the divergenc

M. Bottaccio, A. Amici, P. Miocchi, R. Capuzzo Dolcetta

We study gravitational clustering of mass points in three dimensions with random initial positions and periodic boundary conditions (no expansion) by numerical simulations. Correlation properties are well defined in the system and a sort of thermodynamic limit can be defined for the transient regime of cluste ring. Structure formation proceeds along two path

M. Bottaccio, R. Capuzzo Dolcetta, P. Miocchi, A. Amici

In this talk we discuss some of the main theoretical problems in the understanding of the statistical properties of gravity. By means of N-body simulations we approach the problem of understanding the rôle of gravity in the clustering of a finite set of N-interacting particles which samples a portion of an infinite system. Through the use of the conditional

R. M. Yulmetyev, A. V. Mokshin, P. Hänggi, V. Yu. Shurygin

The realization of idea of time-scale invariance for relaxation processes in liquids has been performed by the memory functions formalism. The best agreement with experimental data for the dynamic structure factor $S(k,ω)$ of liquid cesium near melting point in the range of wave vectors ($0.4 \ang^{-1} \leq k \leq 2.55 \ang^{-1}$) is found with the assumptio

A. V. Zatovsky, V. Lisy

The Zimm equation for the position vector of a polymer segment is generalized taking into account the effect of viscous memory. The Oseen tensor is built on the basis of the nonstationary Navier-Stokes equation. After the preliminary averaging of the tensor a non-Markovian equation for the time correlation function of the Fourier components of the segment po

S. S. Manna, T. Datta, R. Karmakar, S. Tarafdar

The restructuring process of diagenesis in the sedimentary rocks is studied using a percolation type model. The cementation and dissolution processes are modeled by the culling of occupied sites in rarefied and growth of vacant sites in dense environments. Starting from sub-critical states of ordinary percolation the system evolves under the diagenetic rules

H. L. Marshall, N. S. Schulz, T. Fang, W. Cui

Using the Chandra High Energy Transmission Grating Spectrometer (HETGS), we have found significant absorption features in the X-ray spectrum of Cyg X-1 taken in the continuous clocking mode. These features include resonance lines of He-like ions of S, Si, and Mg; the Ly alpha lines of H-like S, Si, Mg, and Ne; and several lower ionization lines of Fe XX, XXI

J. Reunanen, J. K. Kotilainen, M. A. Prieto

We present near-infrared 1.5 - 2.5 micron moderate resolution long-slit spectra of two Seyfert 1 galaxies (NGC 1097 and NGC 1566), three Seyfert 2s (NGC 1386, NGC 4945 and NGC 5128) and one Seyfert 1.5 (NGC 3227), both parallel to ionization cone or jet and perpendicular to it. The spectra are used to study the spatial extent of the line emission, integrated

R. P. Woodard

Quantum gravitational back-reaction offers the potential of simultaneously resolving the problem of the cosmological constant and providing a natural model of inflation in which scalars play no special role. In this model inflation begins because the cosmological constant is not unnaturally small. It ends through the accumulated gravitational interaction bet

Vladimir Privman

We outline a theoretical framework for estimating the evolution of the particle size distribution in colloid and nanoparticle synthesis, when the primary growth mode is by externally controlled addition of singlet building blocks. The master equations, analyzed in the leading &#34;non-diffusive&#34; expansion approximation, are reduced to a set of easily num

Gaston Giribet, Claudio Simeone

Previous analysis about the deparametrization and path integral quantization of cosmological models are extended to models which do not admit an intrinsic time. The formal expression for the transition amplitude is written down for the Taub anisotropic universe with a clear notion of time. The relation existing between the deparametrization associated to gau

Csaba Csaki, Nemanja Kaloper, John Terning

We present a simple model where photons propagating in extra-galactic magnetic fields can oscillate into very light axions. The oscillations may convert some of the photons departing a distant supernova into axions, making the supernova appear dimmer and hence more distant than it really is. Averaging over different configurations of the magnetic field we fi

Hae-Young Kee, Yong Baek Kim

We study the effect of finite chemical potential on the d-density wave state that has been proposed to explain the pseudogap phenomena in underdoped cuprates. We find that the specific heat anomaly at the transition temperature, below which the d-density wave state forms, gets weaker when finite chemical potential is introduced. This provides a useful ground

C. Bachas, J. de Boer, R. Dijkgraaf, H. Ooguri

We study conformal field theories in two dimensions separated by domain walls, which preserve at least one Virasoro algebra. We develop tools to study such domain walls, extending and clarifying the concept of `folding&#39; discussed in the condensed-matter literature. We analyze the conditions for unbroken supersymmetry, and discuss the holographic duals in

Diego A. Wisniacki, Doron Cohen

The idea of perturbation independent decay (PID) has appeared in the context of survival-probability studies, and lately has emerged in the context of quantum irreversibility studies. In both cases the PID reflects the Lyapunov instability of the underlying semiclassical dynamics, and it can be distinguished from the Wigner-type decay that holds in the pertu

Uwe R. Fischer, Gordon Baym

We show that, in the Thomas-Fermi regime, the cores of vortices in rotating dilute Bose-Einstein condensates adjust in radius as the rotation velocity, $Ω$, grows, thus precluding a phase transition associated with core overlap at high vortex density. In both a harmonic trap and a rotating hard-walled bucket, the core size approaches a limiting fraction of t

Giuseppe Iacobucci

The most recent theoretical and experimental results in the field of diffractive scattering are reviewed. A parallel between the two current theoretical approaches to diffraction, the DIS picture in the Breit frame and the dipole picture in the target frame, is given, accompanied by a description of the models to which the data are compared. A recent calcula

J. E. Palomar, S. Hirenzaki, E. Oset

We evaluate radiative decays of $ρ$ and $ω$ going to two neutral mesons, $π^{0} π^{0}$ and $π^{0} η$. We use the sequential vector decay mechanisms in addition to chiral loops and $ρ$-$ω$ mixing. The chiral loops are obtained using elements of $UχPT$ successfully applied in the study of meson-meson interactions up to 1.2 GeV. The chiral loops are found very

A. B. J. Kuijlaars, K. T-R McLaughlin, W. Van Assche, M. Vanlessen

We consider polynomials that are orthogonal on $[-1,1]$ with respect to a modified Jacobi weight $(1-x)^α(1+x)^βh(x)$, with $α,β>-1$ and $h$ real analytic and stricly positive on $[-1,1]$. We obtain full asymptotic expansions for the monic and orthonormal polynomials outside the interval $[-1,1]$, for the recurrence coefficients and for the leading coefficie

P. L. Krotkov, V. P. Mineev

A theory of the upper critical field in a trigonal superconductor with a two-component order-parameter is developed. We demonstrate the existence of sixfold modulations of the upper critical field in the basal plane. The form of the angular dependence of H_c2 in the plane of the main symmetry axis is studied in the whole range of phenomenological rigidity co

Ulf Leonhardt

In diffraction catastrophes such as the rainbow the wave nature of light resolves ray singularities and draws delicate interference patterns. In quantum catastrophes such as the black hole the quantum nature of light resolves wave singularities and creates characteristic quantum effects related to Hawking radiation. The paper describes the theory behind a re

N. Dalal, C. S. Kochanek

We devise a method to measure the abundance of satellite halos in gravitational lens galaxies, and apply our method to a sample of 7 lens systems. After using Monte Carlo simulations to verify the method, we find that substructure comprises fraction f=0.02 (median, 0.006<f<0.07 at 90% confidence) of the mass of typical lens galaxies, in excellent agreement w

Z. G. Dai, T. Lu

We analyze in detail the hydrodynamics and afterglow emission of an ultrarelativistic blast wave when it expands in a density-jump medium. Such a medium is likely to appear in the vicinity of gamma-ray bursts (GRBs) associated with massive stars. The interaction of the blast wave with this medium is described through a reverse shock and a forward shock. We s

Lev Vaidman

It is shown, under the assumption of possibility to perform an arbitrary local operation, that all nonlocal variables related to two or more separate sites can be measured instantaneously, except for a finite time required for bringing to one location the classical records from these sites which yield the result of the measurement. It is a verification measu

CLAS Collaboration, R. De Vita

The double spin asymmetry in the $\vec{e}\vec{p}\to e&#39; π^+ n$ reaction has been measured for the first time in the resonance region for four-momentum transfer $Q^2=0.35-1.5$ GeV$^2$. Data were taken at Jefferson Lab with the CLAS detector using a 2.6 GeV polarized electron beam incident on a polarized solid NH$_3$ target. Comparison with predictions of p