May 1998 arXiv papers — page 8

J. P. Wittmer, A. Milchev, M. E. Cates

We report results of extensive Dynamical Monte Carlo investigations on self-assembled Equilibrium Polymers (EP) without loops in good solvent. (This is thought to provide a good model of giant surfactant micelles.) Using a novel algorithm we are able to describe efficiently both static and dynamic properties of systems in which the mean chain length $\Lav$ i

J. P. Wittmer, A. Milchev, M. E. Cates

We report the results of extensive Dynamic Monte Carlo simulations of systems of self-assembled Equilibrium Polymers without rings in good solvent. Confirming recent theoretical predictions, the mean-chain length is found to scale as $\Lav = \Lstar (ϕ/\phistar)^α\propto ϕ^α\exp(δE)$ with exponents $α_d=δ_d=1/(1+γ) \approx 0.46$ and $α_s = [1+(γ-1)/(νd -1)]/2

J. P. Wittmer, A. Johner

In systems such as block copolymer mesophases or physical gels formed by associating copolymers, the dynamical properties are often controlled by the extraction/association of a sticking group. We propose a description of the extraction/association process of a single sticker. The statistical physics of these associated systems is usually dominated by stretc

C. B. Hanna, A. H. MacDonald, S. M. Girvin

Application of a sufficiently strong parallel magnetic field $B_\parallel > B_{c}$ produces a soliton-lattice (SL) ground state in a double-layer quantum Hall system. We calculate the ground-state properties of the SL state as a function of $B_\parallel$ for total filling factor $ν_{T}=1$, and obtain the total energy, anisotropic SL stiffness, Kosterlitz-Tho

P. Raychaudhuri, T. K. Nath, A. K. Nigam, R. Pinto

It has been observed that in bulk and polycrystalline thin films of collossal magnetoresistive (CMR) materials the magnetoresistance follows a different behaviour compared to single crystals or single crystalline films below the ferromagnetic transition temperature Tc. In this paper we develop a phenomenological model to explain the magnetic field dependence

S. McNamara, S. Luding

We calculate and verify with simulations the ratio between the average translational and rotational energies of systems with rough, inelastic particles, either forced or freely cooling. The ratio shows non-equipartition of energy. In stationary flows, this ratio depends mainly on the particle roughness, but in nonstationary flows, such as freely cooling gran

Dirk Helbing

Several types of stochastic equations are important in thermodynamics, chemistry, evolutionary biology, population dynamics and quantitative social science. For systems with pair interactions four different types of equations are derived, starting from a master equation for the state space: First, general mean value and (co)variance equations. Second, Boltzm

S. Rombouts, K. Heyde, N. Jachowicz

In this work we present a novel quantum Monte-Carlo method for fermions, based on an exact decomposition of the Boltzmann operator $exp(-βH)$. It can be seen as a synthesis of several related methods. It has the advantage that it is free of discretization errors, and applicable to general interactions, both for ground-state and finite-temperature calculation

P. Miller, J. K. Freericks, E. J. Nicol

We calculate the effects of vertex corrections, of non-constant density of states and of a (self-consistently determined) phonon self-energy for the Holstein model on a 3D cubic lattice. We replace vertex corrections with a Coulomb pseudopotential, mu*, adjusted to give the same Tc, and repeat the calculations, to see which effects are a distinct feature of

Yupeng Wang

We propose an integrable model of the spin-1/2 Heisenberg chain coupled to two impurity moments. With the open boundary conditions at the impurity sites, the model can be exactly solved for arbitrary impurity spin and arbitrary exchange constants between the bulk and the impurities. The absence of redundant terms in the hamiltonian makes the model very reaso

M. Mueller, J. P. Wittmer, M. E. Cates

Unconcatenated, unknotted polymer rings in the melt are subject to strong interactions with neighboring chains due to the presence of topological constraints. We study this by computer simulation using the bond-fluctuation algorithm for chains with up to N=512 statistical segments at a volume fraction Φ=0.5 and show that rings in the melt are more compact th

H. Kuroe, H. Seto, J. Sasaki, T. Sekine

We have studied the spin-Peierls (SP) transition in alpha'-Na_{1-delta}V_2O_5 (delta = 0, 0.01 and 0.1) by means of Raman scattering. At room temperature, we observe six A_1 and three A_2 phonon modes and a broad Raman band. Below T_{SP}several new peaks and a new broad band appear. The new peak at 62 cm^{-1} originates from the SP-gap excitation. The ne

S. McNamara, S. Luding

We study vibrated granular media, investigating each of the three components of the energy flow: particle-particle dissipation, energy input at the vibrating wall, and particle-wall dissipation. Energy dissipated by interparticle collisions is well estimated by existing theories when the granular material is dilute, and these theories are extended to include

A. Garcia-Martin, J. A. Torres, J. J. Saenz, M. Nieto-Vesperinas

Exact calculations of transmission and reflection coefficients in surface randomly corrugated optical waveguides are presented. As the length of the corrugated part of the waveguide increases, there is a strong preference to forward coupling through the lowest mode. An oscillating behavior of the enhanced backscattering as a function of the wavelength is pre

J. P. Wittmer, M. E. Cates, A. Johner, M. S. Turner

We consider the growth of a polymer layer on a flat surface in a good solvent by in-situ polymerization. This is viewed as a modified form of diffusion-limited aggregation without branching. We predict theoretically the formation of a pseudo-brush with density rhog(z) \propto z^{-2/3} and characteristic height \propto t^{3}. These results are found by combin

Elka Korutcheva, F. Javier de la Rubia

We investigate the critical dynamics of the time-dependent Landau-Ginzburg model with non conserved n-component order parameter (Model A) in the presence of long-range correlated quenched impurities. We use a special kind of long-range correlations, previously introduced by Weinrib and Halperin. Using a double expansion in εand δwe calculate the critical exp

Dirk Helbing, Peter Molnar

It is suggested that the motion of pedestrians can be described as if they would be subject to `social forces'. These `forces' are not directly exerted by the pedestrians' personal environment, but they are a measure for the internal motivations of the individuals to perform certain actions (movements). The corresponding force concept is discusse

J. Suzuki

Motivated by the recent development on the exact thermodynamics of 1D quantum systems, we propose quasi-particle like formulas for $\hat{\mathfrak{sl}(n)}_{k=1}$ characters. The $\hat{\mathfrak{sl}(2)}_{k=1}$ case is re-examined first. The novel formulation yields a direct connection to the fractional statistics in the short range interacting model, and prov

J. Suzuki

We investigate a 1D quantum system associated with the Ising model in a field(the dilute $A_3$ model) by the recently developed quantum transfer matrix (QTM) approach. A closed set of functional relations is found among variants of fusion QTMs which are characterized by skew Young tableaux. These relations are proved by using a quantum analogue of Jacobi-Tru

O. Zobay, E. M. Wright, P. Meystre

We discuss a method to launch gap soliton-like structures in atomic Bose-Einstein condensates confined in optical traps. Bright vector solitons consisting of a superposition of two hyperfine Zeeman sublevels can be created for both attractive and repulsive interactions between the atoms. Their formation relies on the dynamics of the atomic internal ground st

Koichi Fujimoto, Kunihiko Kaneko

Unidirectionally coupled dynamical system is studied by focusing on the input (or boundary) dependence. Due to convective instability, noise at an up-flow is spatially amplified to form an oscillation. The response, given by the down-flow dynamics, shows both analogue and digital changes, where the former is represented by oscillation frequency and the latte

Rui Carvalho, R. Vilela Mendes, Joao Seixas

We study dynamical systems composed of a set of linearly coupled quadratic maps which, if uncoupled, would be on the Feigenbaum accumulation point. For two units we prove the existence of an infinite number of sinks for an open set of coupling parameters. In the limit of many units a mean field analysis also implies the stabilization in periodic orbits of, a

A. S. Wilson, A. L. Roy, J. S. Ulvestad, E. J. M. Colbert

In this paper, we report VLBA radio maps at three frequencies and an ASCA X-ray spectrum of the water megamaser galaxy NGC 2639, which is believed to contain an edge-on viewed accretion disk. The radio observations reveal a compact ($<$ 0.2 pc) nuclear source with a spectrum that turns over sharply near 5 GHz. The X-ray spectrum shows emission in excess of a

Richard N. Henriksen, Lawrence M. Widrow

Navarro, Frenk, and White have suggested that the density profiles of simulated dark matter halos have a ``universal&#39;&#39; shape so that a given halo can be characterized by a single free parameter which fixes its mass. In this paper, we revisit the spherical infall model in the hope of recognizing in detail the existence and origin of any such universal

Bronson Messer, Anthony Mezzacappa, Steve Bruenn, Mike Guidry

We compare Newtonian three-flavor multigroup Boltzmann (MGBT) and (Bruenn&#39;s) multigroup flux-limited diffusion (MGFLD) neutrino transport in postbounce core collapse supernova environments. We focus our study on quantities central to the postbounce neutrino heating mechanism for reviving the stalled shock. Stationary-state three-flavor neutrino distribut

Adam Frank

Hypersonic bipolar outflows are a ubiquitous phenomena associated with both young and highly evolved stars. Observations of Planetary Nebulae, the nebulae surrounding Luminous Blue Variables such as $η$ Carinae, Wolf Rayet bubbles, the circumstellar environment of SN 1987A and Young Stellar Objects all revealed high velocity outflows with a wide range of sha

Henrique R. Schmitt

This paper presents a comparative study of emission line ratios of the Narrow Line Region (NLR) of Seyfert 1 and Seyfert 2 galaxies. It includes a literature compilation of the emission line fluxes [OII]3727A, [NeIII]3869A, [OIII]5007A and [NeV]3426A, as well as 60mum continuum flux, for a sample of 52 Seyfert 1&#39;s and 68 Seyfert 2&#39;s. The distribution

F. M. Zerbi, L. Mantegazza, S. Campana, E. Antonello

In this paper we revise and complete the photometric survey of the instability strip of the southern open cluster NGC 2516 published by Antonello and Mantegazza (1986). No variable stars with amplitudes larger than $0^m.02$ were found. However by means of an accurate analysis based on a new statistical method two groups of small amplitude variables have been

Eline Tolstoy, J. S. Gallagher, A. A. Cole, J. G. Hoessel

The unprecedented detail of the WFPC2 colour-magnitude diagrams of the resolved stellar population of Leo A presented here allows us to determine a new distance and an accurate star formation history for this extremely metal-poor Local Group dwarf irregular galaxy. From the position of the red clump, the helium-burning blue loops and the tip of the red giant

C. Steidel, K. Adelberger, M. Giavalisco, M. Dickinson

Galaxies at very high redshift (z~3 or greater) are now accessible to wholesale observation, making possible for the first time a robust statistical assessment of their spatial distribution at lookback times approaching ~90% of the age of the Universe. This paper summarizes recent progress in understanding the nature of these early galaxies, concentrating in

S. Moehler, U. Heber

Two high galactic latitude B-type stars, PG1323-086 and PG1704+222, are analysed from low and medium resolution optical spectra and Stroemgren photometry. A differential abundance analysis for He, C, N, O, Mg, Al, and Si reveals that the He abundance is close to solar while metal underabundances relative to the solar value of typically 1.3 and 1.2 dex for PG

B. S. Sathyaprakash, Varun Sahni, Sergei F. Shandarin, Karl B. Fisher

We explore shapes of clusters and superclusters in the IRAS 1.2 Jy redshift survey with three reconstructions spanning the range β= 0.1, 0.5, 1.0, where β= Ω^{0.6}/b, b is the bias factor and Ωthe present value of the dimensionless matter density. Comparing our results to Gaussian randomized reconstructions of the IRAS catalogue, we find structures having bo

Tomonori Totani

Gamma-ray bursts (GRBs) and following afterglows are considered to be produced by dissipation of kinetic energy of a relativistic fireball and radiation process is widely believed as synchrotron radiation or inverse Compton scattering of electrons. We argue that the transfer of kinetic energy of ejecta into electrons may be inefficient process and hence the

Tomonori Totani, Yuzuru Yoshii

We have performed a detailed V/Vmax test for a sample of the Canada-France Redshift Survey (CFRS) for the purpose of examining whether the comoving number density of field galaxies changes significantly at redshifts of z<1. Taking into account the luminosity evolution of galaxies which depends on their morphological type through different history of star for

D. V. Bisikalo, A. A. Boyarchuk, V. M. Chechetkin, O. A. Kuznetsov

The results of 3D hydrodynamic simulation of mass transfer in semidetached binaries of different types (cataclysmic variables and low-mass X-ray binaries) are presented. We find that taking into account of a circumbinary envelope leads to significant changes in the stream-disc morphology. In particular, the obtained steady-state self-consistent solutions sho

J. M. Overduin, F. I. Cooperstock

Evolution of the scale factor a(t) in Friedmann models (those with zero pressure and a constant cosmological term Lambda) is well understood, and elegantly summarized in the review of Felten and Isaacman [Rev. Mod. Phys. 58, 689 (1986)]. Developments in particle physics and inflationary theory, however, increasingly indicate that Lambda ought to be treated a

J. Lopez-Suarez, R. Canal

We present a model for big bang nucleosynthesis which combines baryon inhomogeneities with the effects of the decays of massive particles (masses higher than a few GeV). Those particles, with half-lives longer than the standard nucleosynthesis epoch, give rise to both electromagnetic and hadron cascades which modify the abundances of the light nuclides resul

Xuelei Chen, Marc Kamionkowski

We calculate the cross section for s-wave neutralino annihilation to three-body final states below the W^+ W^- and t-bar t thresholds. Such three-body channels may dominate the annihilation cross section if the neutralino mass is not too much less than m_t and m_W respectively. Furthermore, because neutrinos produced in these channels are much more energetic

Hermann Riecke, Lorenz Kramer

We determine the modulational stability of standing waves with small group velocity in quasi-onedimensional systems slightly above the threshold of a supercritical Hopf bifurcation. The stability limits are given by two different long-wavelength destabilisation mechanisms and generically also a short-wavelength destabilisation. The Eckhaus parabola is shifte

Stephan Dürr

We consider the N_f-flavour Schwinger Model on a thermal cylinder of circumference $β=1/T$ and of finite spatial length $L$. On the boundaries $x^1=0$ and $x^1=L$ the fields are subject to an element of a one-dimensional class of bag-inspired boundary conditions which depend on a real parameter $θ$ and break the axial flavour symmetry. For the cases $N_f=1$

Robert B. Griffiths

An analysis using classical stochastic processes is used to construct a consistent system of quantum counterfactual reasoning. When applied to a counterfactual version of Hardy&#39;s paradox, it shows that the probabilistic character of quantum reasoning together with the ``one framework&#39;&#39; rule prevents a logical contradiction, and there is no eviden

Ashfaq S. Thanawalla, S. K. Dutta, C. P. Vlahacos, D. E. Steinhauer

We describe the use of a cryogenic near-field scanning microwave microscope to image microwave electric fields from superconducting and normal-metal microstrip resonators. The microscope employs an open-ended coaxial probe and operates from 77 to 300 K in the 0.01-20 GHz frequency range with a spatial resolution of about 200 mm. We describe the operation of

D. I. Golosov, M. R. Norman, K. Levin

In the CMR materials, ferromagnetic double exchange (DE) presumably coexists with a direct nearest-neighbour antiferromagnetic interaction. We construct a single-site mean field theory that explicitly takes into account the different nature of carrier-mediated ferromagnetism vs. Heisenberg-like superexchange. We find, in contrast to previous results in the l

Shmuel Elitzur, Oskar Pelc, Eliezer Rabinovici

Confinement and Screening are investigated in SUSY gauge theories, realized by an M5 brane configuration, extending an approach applied previously to N=1 SYM theory, to other models. The electric flux tubes are identified as M2 branes ending on the M5 branes and the conserved charge they carry is identified as a topological property. The group of charges car

Paolo Bellomo, C. R. Stroud,, David Farelly, T. Uzer

The complex processes leading to the collisional population of ultra-long-lived Rydberg states with very high angular momentum can be explained surprisingly well using classical mechanics. In this article, we explain the reason behind this striking agreement between classical theory and experiment by showing that the classical and quantum dynamics of Rydberg

R. Calemczuk, J. Riera, D. Poilblanc, J. -P. Boucher

Specific heat ($C_V$) measurements in the spin-1/2 Cu$_2$(C$_2$H$_{12}$N$_2$)$_2$Cl$_4$ system under a magnetic field up to $H=8.25 T$ are reported and compared to the results of numerical calculations based on the 2-leg antiferromagnetic Heisenberg ladder. While the temperature dependences of both the susceptibility and the low field specific heat are accur

J. J. Halliwell

We investigate a detector scheme designed to measure the arrival of a particle at $x=0$ during a finite time interval. The detector consists of a two state system which undergoes a transition from one state to the other when the particle crosses $x=0$, and possesses the realistic feature that it is effectively irreversible as a result of being coupled to a l

Sumati Surya, Donald Marolf

We address the delocalization of low dimensional D-branes and NS-branes when they are a part of a higher dimensional BPS black brane, and the homogeneity of the resulting horizon. We show that the effective delocalization of such branes is a classical effect that occurs when localized branes are brought together. Thus, the fact that the few known solutions w

M. Caffo, H. Czyz, S. Laporta, E. Remiddi

The master differential equations in the external square momentum p^2 for the master integrals of the two-loop sunrise graph, in n-continuous dimensions and for arbitrary values of the internal masses, are derived. The equations are then used for working out the values at p^2 = 0 and the expansions in p^2 at p^2 =0, in (n-4) at n to 4 limit and in 1/p^2 for

W. de Boer, H. J. Grimm, A. V. Gladyshev, D. I. Kazakov

New limits on the Higgs mass from LEP and new calculations on the radiative (penguin) decay of the b->s gamma branching ratio restrict the parameter space of the Constrained Minimal Supersymmetric Standard Model (CMSSM). We find that for the low tan(beta) scenario only one sign of the Higgs mixing parameter is allowed, while the high tan(beta scenario is pra

Gian F. Giudice, Alexander Kusenko

We argue that in the minimal supersymmetric extension of the Standard Model with a large trilinear coupling both the fundamental Higgs boson and a bound state of squarks (formed via strong scalar interaction) can have a non-zero VEV. This alters drastically the pattern of electroweak-symmetry breaking and the Higgs phenomenology. In particular, the upper bou

Alexander Vilenkin

Models of open inflation with a variable density parameter $Ω$ provide the most natural way to reconcile an open universe with inflation. The use of anthropic principle is essential to derive observational predictions of such models. I discuss how this principle can be used in a quantitative way to determine the most probable value of $Ω$. I also comment on

John Ellis, Zygmunt Lalak, Stefan Pokorski, Witold Pokorski

We discuss the reduction of the eleven-dimensional M-theory effective Lagrangian, considering first compactification from eleven to five dimensions on a Calabi-Yau manifold, followed by reduction to four dimensions on an S_1/Z_2 line segment at a larger distance scale. The Calabi-Yau geometry leads to a structure of the five-dimensional Lagrangian that has m

P. Thalmeier, P. Fulde

Recent X-ray analysis and NMR- experiments have shown that alpha&#39;- NaV2O5 is not a conventional spin-Peierls (SP) compound because above the transition at 33K it is in a homogeneous mixed valent (MV) state and atomic spin chains do not exist. Furthermore, thermal expansion experiments have identified the existence of a double phase transition. We present

Mona Berciu, Sajeev John

We evaluate from first principles the self-consistent Hartree-Fock energies for multi-soliton configurations in a doped, spin-1/2, antiferromagnetic Mott insulator on a two-dimensional square lattice. We find that nearest-neighbor Coulomb repulsion stabilizes a regime of charged meron-antimeron vortex soliton pairs over a region of doping from 0.05 to 0.4 ho

Daniel M. Kaplan, Charles. E. Lane, Kenneth S. Nelson

An introductory review, suitable for the beginning student of high-energy physics or professionals from other fields who may desire familiarity with subatomic-particle detection techniques. Subatomic-particle fundamentals and the basics of particle interactions with matter are summarized, after which we review particle detectors. We conclude with three examp

Peter M. Levy, Sadamichi Maekawa, Patrick Bruno

We have considered the effects of non magnetic impurities and interface roughness on the interlayer coupling between magnetic layers in metallic multilayers. The two types of defects alter the interlayer coupling in quite different ways. Elastic electron scattering by impurities in the non magnetic spacer layers between magnetic layers produces an exponentia

Abhay Shukla, Bernardo Barbiellini, Andreas Erb, Alfred A. Manuel

The (mostly) insulating behaviour of PrBa2Cu3O7-d is still unexplained and even more interesting since the occasional appearance of superconductivity in this material. Since YBa2Cu3O7-d is nominally iso-structural and always superconducting, we have measured the electron momentum density in these materials. We find that they differ in a striking way, the wav

G. Feverati, F. Ravanini, G. Takacs

We examine the connection between the nonlinear integral equation (NLIE) derived from light-cone lattice and sine-Gordon quantum field theory, considered as a perturbed c=1 conformal field theory. After clarifying some delicate points of the NLIE deduction from the lattice, we compare both analytic and numerical predictions of the NLIE to previously known re

Ken-ichiro Imura, Kazusumi Ino

We study the edge transport properties of paired fractional quantum Hall (FQH) states--- the Haldane-Rezayi (HR), Moore-Read (Pfaffian) and Halperin (331) states. A table of exponents is given for the tunneling between the edges of paired FQH states in gated 2D structures and the tunneling into the edge of FQH states from a normal Fermi liquid (N). It is fou

Hong-Yi Zhou, Chong-Sheng Li

The $\alpha m_t^2/m_W^2$ order supersymmetric electroweak corrections arising from loops of chargino, neutralino, and squark to top quark pair production by $gg$ fusion at LHC are calculated in the minimal supersymmetric model. We found that the corrections amount about a few percent.

Alessio Filippetti, Vincenzo Fiorentini, Giancarlo Cappellini, Andrea Bosin

Relaxations at nonpolar surfaces of III-V compounds result from a competition between dehybridization and charge transfer. First principles calculations for the (110) and (10$\bar{1}$0) faces of zincblende and wurtzite AlN, GaN and InN reveal an anomalous behavior as compared with ordinary III-V semiconductors. Additional calculations for GaAs and ZnO sugges

A. Misra, D. S. Koltun

We develop a method for constructing the Heavy Baryon Chiral Perturbation Theory Lagrangian (L_{HBChPT}), to a given chiral order, within HBChPT. We work within SU(2) theory, with only the pion field interacting with the nucleon. The main difficulties, which are solved, are to develop techniques for implementing charge conjugation invariance, and for taking

Tomohiro Harada, Hideo Iguchi, Ken-ichi Nakao

We investigate collapse of a spherical cloud of counter-rotating particles. An explicit solution is given using an elliptic integral. If the specific angular momentum $L(r)=O(r^2)$ at $r\to 0$, no central singularity occurs. With $L(r)$ like that, there is a finite region around the center that bounces. On the other hand, if the order of $L(r)$ is higher tha

Xiangdong Shi, George Fuller, Francis Halzen

It has been suggested that the supermassive black holes, at the centers of galaxies and quasars, may initially form in single collapses of relativistic star clusters or supermassive stars built-up during the evolution of dense star clusters. We show that it may be possible for ICECUBE (a planned 1 km^3 neutrino detector in Antarctica) to detect the neutrino

E. P. Raposo, D. Bazeia

We describe exact kink soliton solutions to nonlinear partial differential equations in the generic form u_{t} + P(u) u_{x} + νu_{xx} + δu_{xxx} = A(u), with polynomial functions P(u) and A(u) of u=u(x,t), whose generality allows the identification with a number of relevant equations in physics. We emphasize the study of chirality of the solutions, and its r

Z. Popowicz

We preesent a new supersymmetric integrable extensions of the a=4,N=2 KdV hierarchy. The root of the supersymmetric Lax operator of the KdV equation is generalized, by including additional fields. This generalized root generate new hierarchy of integrable equations, for which we investigate the hamiltonian structure. In special case our system describes the

C. Anastopoulos

We study information measures in quantu mechanics, with particular emphasis on providing a quantification of the notions of classicality and predictability. Our primary tool is the Shannon - Wehrl entropy I. We give a precise criterion for phase space classicality and argue that in view of this a) I provides a measure of the degree of deviation from classica

Vesselin Petkov

Since the shape of a free body&#39;s worldline is determined by the geometry of spacetime a local change of spacetime geometry will affect a body&#39;s worldline, i.e. a body&#39;s state of motion. The exploration of this possibility constitutes a radically new approach to the idea of how a body can be propelled: instead of applying a force to the body itsel

J. P. Bondorf, A. S. Botvina, I. N. Mishustin

A systematic comparison of different isotopic temperatures with the thermodynamical temperature of a multifragment system is made on the basis of the Statistical Multifragmentation Model. It is demonstrated that isotopic temperatures are strongly affected by the secondary decays of hot primary fragments and the population of particle-stable excited states in

J. L. Forest, V. R. Pandharipande, A. Arriaga

Relativistic Hamiltonians are defined as the sum of relativistic one-body kinetic energy, two- and three-body potentials and their boost corrections. In this work we use the variational Monte Carlo method to study two kinds of relativistic effects in the binding energy of 3H and 4He. The first is due to the nonlocalities in the relativistic kinetic energy an

I. Vidaña, A. Polls, A. Ramos, M. Hjorth-Jensen

Single-particle energies of the $Λ$ and $Σ$ hyperons are obtained from the relevant self-energies. The latter are constructed within the framework of a perturbative many-body approach employing present realistic hyperon-nucleon interactions such as the models of the Juelich and Nijmegen groups. The effects of the non-locality and energy dependence of the sel

S. B. Dubovichenko

The three variant of the potentials with tensor part and ioao containing unobservable forbidden states and having one fitted parameter are considered. Parameter of such potentials is fixed only on the base low energy NN characteristics and deuteron binding energies. The NN characteristics at high energies, deuteron properties and formfactors up to 6 Fm-1 is

Dario Bambusi, Sandro Graffi, Thierry Paul

Let ${\cal H}(x,ξ)$ be a holomorphic Hamiltonian of quadratic growth on $ R^{2n}$, $b$ a holomorphic exponentially localized observable, $H$, $B$ the corresponding operators on $L^2(R^n)$ generated by Weyl quantization, and $U(t)=\exp{iHt/\hbar}$. It is proved that the $L^2$ norm of the difference between the Heisenberg observable $B_t=U(t)BU(-t)$ and its se

Glenn G. Chappell

Given a set D of positive integers, the associated distance graph on the integers is the graph with the integers as vertices and an edge between distinct vertices if their difference lies in D. We investigate the chromatic numbers of distance graphs. We show that, if $D = {d_1,d_2,d_3,...}$, with $d_n | d_{n+1}$ for all n, then the distance graph has a prope

W. Barth

By a K3-surface with nine cusps I mean a compact complex surface with nine isolated double points $A_2$, but otherwise smooth, such that its minimal desingularisation is a K3-surface. In an earlier paper I showd that each such surface is a quotient of a complex torus by a cyclic group of order three. Here I try to classify these $K3$-surfaces, using the peri

S. A. Merkulov

It is shown that the de Rham complex of a symplectic manifold $M$ satisfying the hard Lefschetz condition is formal. Moreover, it is shown that the differential Gerstenhaber-Batalin-Vilkoviski algebra associated to such a symplectic structure gives rise, along the lines explained in the papers of Barannikov and Kontsevich [alg-geom/9710032] and Manin [math/9

Laurent Baulieu, Eliezer Rabinovici

We discuss theories containing higher-order forms in various dimensions. We explain how Chern--Simons-type theories of forms can be defined from TQFTs in one less dimension. We also exhibit new TQFTs with interacting Yang--Mills fields and higher--order forms. They are obtained by the dimensional reduction of TQFTs whose gauge functions are free self-duality

John Ellis, N. E. Mavromatos, D. V. Nanopoulos

We discuss the treatment of quantum-gravitational fluctuations in the space-time background as an `environment&#39;, using the formalism for open quantum-mechanical systems, which leads to a microscopic arrow of time. After reviewing briefly the open-system formalism, and the motivations for treating quantum gravity as an `environment&#39;, we present an exa

Tsuguhiko Asakawa, Taichiro Kugo, Tomohiko Takahashi

The generalized gluing and resmoothing theorem originally proved by LeClair, Peskin and Preitschopf, gives a powerful formula for the fused vertex obtained by contracting any two vertices in string field theories. Although the theorem is naturally expected to hold for the vertices at any loop level, the original proof was restricted to the vertices at tree l

Diana Vaman, Mihai Visinescu

We review the geodesic motion of pseudo-classical spinning particles in curved spaces. Investigating the generalized Killing equations for spinning spaces, we express the constants of motion in terms of Killing-Yano tensors. The general results are applied to the case of the four-dimensional Euclidean Taub-NUT spinning space. A simple exact solution, corresp

L. Susskind

Large N gauge theories have so called Gross-Witten phase transitions which typically can occur in finite volume systems. In this paper we relate these transitions in supersymmetric gauge theories to transitions that take place between black hole solutions in general relativity. The correspondence between gauge theory and gravitation is through matrix theory

L. Susskind, Edward Witten

The correspondence between string theory in Anti-de Sitter space and super Yang Mills theory is an example of the Holographic principle according to which a quantum theory with gravity must be describable by a boundary theory. However, arguments given so far are incomplete because, while the bulk theory has been related to a boundary theory, the holographic

James N. Hormuzdiar, Stephen D. H. Hsu

We describe a class of pionic breather solutions (PBS) which appear in the chiral lagrangian description of low-energy QCD. These configurations are long-lived, with lifetimes greater than $10^3$ fm/c, and could arise as remnants of disoriented chiral condensate (DCC) formation at RHIC. We show that the chiral lagrangian equations of motion for a uniformly i

M. Diehl, T. Gousset

We explain why the time ordering in the definition of non-diagonal parton distributions can be omitted and discuss the physics implications.

M. Diehl, T. Gousset, B. Pire, O. Teryaev

Hadron pair production gamma* gamma -> h hbar in the region where the c.m. energy is much smaller than the photon virtuality can be described in a factorized form, as the convolution of a partonic handbag diagram and generalized distribution amplitudes which are new non-perturbative functions describing the exclusive fragmentation of a quark-antiquark pair i

Shuquan Nie, Marc Sher

In the two-Higgs doublet extension of the standard model, flavor-changing neutral couplings arise naturally. In the lepton sector, the largest such coupling is expected to be $μ-τ-ϕ#. We consider the effects of this coupling on the anomalous magnetic moment of the muon. The resulting bound on the coupling, unlike previous bounds, is independent of the value

I. F. Ginzburg, U. D. Jentschura, S. G. Karshenboim, F. Krauss

Dimuonium (the bound system of two muons, $μ^+μ^-$-atom) has not been observed yet. In this paper we discuss the electromagnetic production of dimuonium at RHIC and LHC in relativistic heavy ion collisions. The production of parastates is analyzed in the equivalent photon approximation. For the treatment of orthostates, we develop a three photon formalism. W

Apostolos Pilaftsis

In the minimal supersymmetric Standard Model, the heaviest CP-even Higgs boson H and the CP-odd Higgs scalar A are predicted to be almost degenerate in mass at the tree level, for the wide kinematic range M_A > 2M_Z and \tanβ\ge 2. However, if large soft-CP-violating Yukawa interactions involving scalar quarks of the third generation are present in the theor

G. G. Bunatian

In the work presented, the decay of the pionium, that is the π^+ π^- bound state, into two π^0 is studied, the ππ-interaction causing this transition being described by the underlying Weinberg lagrangian. The calculation with such a ππ-lagrangian being carried out, the π-meson size r_{0}-emerges to be allowed for and occurs in the final result. The bound π^+

Sven Moch

The leading and next-to-leading threshold logarithms of the QCD corrections to electroproduction of heavy quarks in single-particle inclusive kinematics are resummed to all orders in perturbation theory. The resummed cross-section is used to derive the NLO and NNLO results near threshold and their numerical impact on the charm structure function is studied.

Rahul Basu

In this talk I review the behaviour of structure functions at low values of Bjorken $x$ and discuss the theoretical underpinnings with particular attention to resummation schemes. I present the need for &#39;less inclusive&#39; events to distinguish between various resummation schemes and discuss the various difficulties in differentiating experimentally bet

S. M. Bilenky, C. Giunti, W. Grimus

All the possible schemes of neutrino mixing with four massive neutrinos inspired by the existing experimental indications in favour of neutrino mixing are considered. It is shown that the scheme with a neutrino mass hierarchy is not compatible with the experimental results, likewise all other schemes with the masses of three neutrinos close together and the

J. Hisano, Daisuke Nomura, Yasuhiro Okada, Yasuhiro Shimizu

Branching ratio of $μ\to \e γ$ is evaluated in the supersymmetric SU(5) grand unified theory taking account of higher dimensional operators, which reproduce the realistic quark and lepton masses and the mixing parameters. It is shown by numerical calculation that at large $\tanβ$ the branching ratio is enhanced by a few orders of magnitude since the flavor m

J. H. Vossebeld

Photoproduction of jets at HERA provides information on the partonic structure of the photon. We report on the latest dijet photoproduction results, for real photons and for photons at low virtualities, measured with the ZEUS detector.

Diego F. Torres, Gustavo E. Romero, Luis A. Anchordoqui

In this essay, we assume that negative mass objects can exist in the extragalactic space and analyze the consequences of their microlensing on light from distant Active Galactic Nuclei. We find that such events have very similar features to some observed Gamma Ray Bursts and use recent satellite data to set an upper bound to the amount of negative mass in th

C. Anastopoulos

Motivated by the consistent histories approach to quantum mechanics, we examine a simple model of hydrodynamic coarse-graining for a scalar field. It consists in averaging the field over spatial regions of size L and constructing the evolution equation for the coarse grained quantities, thus identifying dissipation and noise.

Edmund J. Copeland, Andrew R. Liddle, James E. Lidsey, David Wands

Two strands of observational gravitation, one the search for astrophysical evidence of primordial black holes and the other the search for gravitational waves, may combine to provide strong evidence in favour of cosmological models based on superstring theory, the leading candidate for unifying gravity with the other fundamental forces.

Jerome Martin, Dominik J. Schwarz

We study the influence of reheating on super-horizon density perturbations and gravitational waves. We correct wrong claims [L. P. Grishchuk Phys. Rev. D 50, 7154 (1994) and gr-qc/9801011] about the joining of perturbations at cosmological transitions and about the quantization of cosmological perturbations.

T. Jungwirth, S. P. Shukla, L. Smrcka, M. Shayegan

We show that the sign of magnetic anisotropy energy in quantum Hall ferromagnets is determined by a competition between electrostatic and exchange energies. Easy-axis ferromagnets tend to occur when Landau levels whose states have similar spatial profiles cross. We report measurements of integer QHE evolution with magnetic-field tilt. Reentrant behavior obse