December 1999 arXiv papers — page 23

Michael Binger, Chueng-Ryong Ji, David G. Robertson

We discuss application of the physical QCD effective charge $α_V$, defined via the heavy-quark potential, in perturbative calculations at next-to-leading order. When coupled with the Brodsky-Lepage-Mackenzie prescription for fixing the renormalization scales, the resulting series are automatically and naturally scale and scheme independent, and represent una

U S Nilsson, M J Hancock, J Wainwright

We consider the late time behaviour of non-tilted perfect fluid Bianchi VII_0 models when the source is a radiation fluid, thereby completing the analysis of the Bianchi VII_0 models initiated by Wainwright et al in a recent paper. The models exhibit the phenomena of asymptotic self-similarity breaking and Weyl-curvature dominance at late times. The late tim

Leor Barack, Amos Ori

We outline a method for calculating the self force (the "radiation reaction force") acting on a scalar particle in a strong field orbit in a Schwarzschild spacetime. In this method, the contribution to the self force associated with each multipole mode of the particle's field is calculated separately, and the sum over modes is then evaluated, sub

Yehuda Goldin, Yshai Avishai

Nonlinear tunneling current through a quantum dot (an Anderson impurity system) subject to both constant and alternating electric fields is studied in the Kondo regime. A systematic diagram technique is developed for perturbation study of the current in physical systems out of equilibrium governed by time - dependent Hamiltonians of the Anderson and the Kond

Tim Gebbie

I outline some nonperturbative relativistic effects that arise from gravitational corrections to the Boltzmann equations. These may be important for the study of CMB temperature anisotropies, particularly their interpretation. These terms are not included in the canonical treatment as they arise from the exact equations. Here a weakly nonlinear investigation

John Womersley

I describe the current status of tests of perturbative QCD, using measurements of jet, photon, weak boson and heavy flavor production from the Tevatron, LEP and HERA. Measurements of the strong coupling constant are described, and I conclude with a "wish list" for the future.

Roger Alperin

Using a quartic surface and its rational curves we can give an infinite number of integer hexahedra; these are 6 sided 3d solids, each face a trapezoid, with all sides and diagonals having intger lengths.

Takeshi Sato

We discuss some properties of an M-9-brane in ``massive 11D theory'' proposed by Bergshoeff, Lozano and Ortin. A 10-form gauge potential is consistently introduced into the massive 11D supergravity, and an M-9-brane Wess-Zumino action is constructed as that of a gauged $σ$-model. Using duality relations is crucial in deriving the action, which we lea

Vladimir P. Gerdt, Vladimir V. Kornyak, Matthias Berth, Guenter Czichowski

We consider computational and implementation issues for the completion of monomial sets to involution using different involutive divisions. Every of these divisions produces its own completion procedure. For the polynomial case it yields an involutive basis which is a special form of a Groebner basis, generally redundant. We also compare our Mathematica impl

Vladimir P. Gerdt

In this paper, in addition to the earlier introduced involutive divisions, we consider a new class of divisions induced by admissible monomial orderings. We prove that these divisions are noetherian and constructive. Thereby each of them allows one to compute an involutive Groebner basis of a polynomial ideal by sequentially examining multiplicative reductio

Vladimir P. Gerdt, Yuri A. Blinkov

In this paper we consider an algorithmic technique more general than that proposed by Zharkov and Blinkov for the involutive analysis of polynomial ideals. It is based on a new concept of involutive monomial division which is defined for a monomial set. Such a division provides for each monomial the self-consistent separation of the whole set of variables in

V. Dzhunushaliev

Some nondifferentiable quantities (for example, the metric signature) can be the independent physical degrees of freedom. It is supposed that in quantum gravity these degrees of freedom can fluctuate. Two examples of such quantum fluctuation are considered: a quantum interchange of the sign of two components of the 5D metric and a quantum fluctuation between

Claus O. Wilke, Christopher Ronnewinkel, Thomas Martinetz

We study self-replicating molecules under externally varying conditions. Changing conditions such as temperature variations and/or alterations in the environment's resource composition lead to both non-constant replication and decay rates of the molecules. In general, therefore, molecular evolution takes place in a dynamic rather than a static fitness la

Iver Brevik, Sergei D. Odintsov

We discuss the role of conformal matter quantum effects (using large $N$ anomaly induced effective action) to creation-annihilation of an Anti-de Sitter Universe. The arbitrary GUT with conformally invariant content of fields is considered. On a purely gravitational (supersymmetric) AdS background, the quantum effects act against an (already existing) AdS Un

Kingman Cheung, Otto C. W. Kong

We study the Zee model of neutrino mass in the framework of R-parity violating supersymmetry. Within the matter contents of the minimal supersymmetric standard model, any one of the three right-handed sleptons could be a suitable candidate for the charged-singlet scalar of the Zee model, and one of the Higgs doublets provides the extra necessary vacuum expec

George Chapline

We provide evidence that quantum mechanics can be interpreted as a rational algorithm for finding the least complex description for the correlations in the outputs of sensors in a large array. In particular, by comparing the self-organization approach to solving the Traveling Salesman Problem with a solution based on taking the classical limit of a Feynman p

Leszek Motyka, Mariusz Sadzikowski

We consider inelastic collisions between atoms of different kinds as a potential source of photons in the sonoluminescence phenomena. We estimate the total energy emitted in one flash and the shape of the spectrum and find a rough agreement between the results of our calculation and the experimental data. We conclude that the atomic collisions might be a can

Bong Soo Han, Myung Ki Cheoun, K. S. Kim, Il-Tong Cheon

The kaon photoproduction is analyzed up to $E_γ^{\rm Lab}$=2.0 GeV by using an isobaric model based on effective Lagrangians and by taking a cross symmetry into account. Both {\it pseudovector} and {\it pseudoscalar} couplings for kaon-baryon-baryon (baryon spin=1/2) interactions are considered with form factors. A vector meson($K^*(890)$), an axial vector m

E. Brezin, S. Hikami

In a recent article we have discussed the connections between averages of powers of Riemann's $ζ$-function on the critical line, and averages of characteristic polynomials of random matrices. The result for random matrices was shown to be universal, i.e. independent of the specific probability distribution, and the results were derived for arbitrary mome

Marcos Jardim

This work concerns the study of certain finite-energy solutions of the anti-self-dual Yang-Mills equations on Euclidean 4-dimensional space which are periodic in two directions, so-called doubly-periodic instantons. We establish a circle of ideas involving equivalent analytical and algebraic-geometric descriptions of these objects. In the first introductory

Alexandre A. Panin

We consider the lattice of subsemigroups of the general linear group over an Artinian ring containing the group of diagonal matrices and show that every such semigroup is actually a group.

Z. Bern, A. De Freitas, H. L. Wong

Using relationships between open and closed strings, we present a construction of tree-level scattering amplitudes for gravitons minimally coupled to matter in terms of gauge theory partial amplitudes. In particular, we present examples of amplitudes with gravitons coupled to vectors or to a single fermion pair. We also present two examples with massive grav

Boris Tsirelson

Recent progress in mathematical theory of random processes provides us with non-Fock product systems (continuous tensor products of Hilbert spaces) used here for constructing a toy model for fermions. Some state vectors describe infinitely many particles in a finite region; the particles accumulate to a point. Electric charge can be assigned to the particles

A. N. Mitra

This article has a 3-fold objective: i) to provide a panoramic view of several types of 3D vs 4D approaches in Field Theory (Tamm-Dancoff, Bethe Salpeter Equation (BSE), Quasi-potentials, Light-Front Dynamics, etc) for strong interaction dunamics; ii) to focus on the role of the Markov-Yukawa Transversality Principle (MYTP) as a novel paradigm for an exact 3

S. Oda, T. Yukawa

In order to consider non-perturbative effects of superstrings, we try to apply dynamical triangulations to the type IIB superstrings. The discretized action is constructed from the type IIB matrix model proposed as a constructive definition of superstring theory. The action has the local N=2 supersymmetry explicitly, and has no extra fermionic degrees of fre

Elena Tareyeva, Tatiana Schelkacheva

A simple model for the angular dependent interaction between C_60 molecules on the face-centered cubic lattice is proposed. The bifurcations of the solutions of the nonlinear integral equations for orientational distribution functions in the mean field approximation are analyzed and the orientational phase transition in solid C_60 is described. The quantitat

Elena Tareyeva, Valentin Ryzhov

We present a new purely equilibrium microscopic approach to the description of liquid-glass transition in terms of space symmetry breaking of three- and four-particle distribution functions in the cases of two and three dimensions, respectively. The approach has some features of spin glass theories as well as of density-functional theories of freezing.

Yannick Alméras, Jean-Louis Barrat, Lydéric Bocquet

We briefly discuss how the wetting properties of a fluid/solid interface can indirectly influence the diffusion properties of fluid confined between two solid walls. This influence is related to the variability of the hydrodynamic boundary conditions at the interface, which correlates to the wetting properties.

Shunsaku Hirata

The zero-temperature magnetization process of a one-dimensional S=1/2 spin system with next-nearest-neighbour coupling alpha and anisotropy delta is studied. There is a region in the parameter space where the magnetization has a jump at certain external field. The boundary of this region is determined. The two cases are distinguished according as alpha<1/4 o

Rongping Wang, Yueliang Zhou, Shaohua Pan, Meng He

YBCO films were successfully prepared on biaxially textured Ag{110}<211> substrates by using pulsed laser deposition. X-ray diffraction results showed that the degree of preferential orientation of Ag{110}<211> substrates varied with increasing annealing temperature. With a thin template layer deposited at low temperature, YBCO film with c-axis orientation a

V. Podzorov, M. Uehara, M. E. Gershenson, S-W. Cheong

We observed a dramatic peak in the 1/f noise at the metal-insulator transition (MIT) in low-Tc manganites. This many-orders-of-magnitude noise enhancement is observed for both polycrystalline and single-crystal samples of La{5/8-y}Pr{y}Ca{3/8}MnO{3} (y=0.35-0.4) in zero magnetic field and Pr{1-x}Ca{x}MnO{3} (x=0.35-0.5) in magnetic field. This observation st

F. D. A. Hartwick

We present evidence to support an earlier indication that the Galaxy is embedded in an extended, highly inclined, triaxial halo outlined by the spatial distribution of companion galaxies to the Milky Way. Signatures of this spatial distribution are seen in 1) the angular variation of the radial-velocity dispersion of the companion galaxies, 2) the spatial di

Daniel Stern, Hyron Spinrad

How and when do galaxies form? Studies of the microwave background radiation reveal that the Universe is spectacularly homogenous at redshift z~1000. Observations of the local Universe reveal that by z=0 much of the luminous matter has condensed into mature, gravitationally-bound structures. One of the primary challenges to astronomers today is to achieve a

L. A. Anchordoqui, M. T. Dova, T. P. McCauley, S. Reucroft

A re-examination of the energy cosmic ray spectrum above $10^{20}$ eV is presented. The overall data-base provides evidence, albeit still statistically limited, that non-nucleon primaries could be present at the end of the spectrum. In particular, the possible appearance of superheavy nuclei (seldom discussed in the literature) is analysed in detail.

J. Craig Wheeler, Peter Hoeflich, Lifan Wang, Insu Yi

The polarization of core-collapse supernovae shows that many if not all of these explosions must be strongly bi-polar. The most obvious way to produce this axial symmetry is by the imposition of a jet as an intrinsic part of the explosion process. These jets could arise by MHD processes in the formation of pulsars and be especially strong in the case of magn

George A. Baker,

This paper has been withdrawn by the author because eq.(4) and those subsequent are incorrect.

W. Anthony Mann

New observations with atmospheric neutrinos from the underground experiments SuperKamiokande, Soudan 2, and MACRO, together with earlier results from Kamiokande and IMB, are reviewed. The most recent observations reconfirm aspects of atmospheric flavor content and of zenith angle distributions which appear anomalous in the context of null oscillations. The a

Jose Ramon Espinosa, Ren-Jie Zhang

Starting with the two-loop effective potential of the MSSM, and assuming a supersymmetric scale well above $M_Z$, we derive a simple analytical approximation for the lightest CP-even Higgs boson mass including resummation of higher order logarithmic terms via RG-improvement and finite non-logarithmic terms up to ${\cal O}(α_sα_t)$. This formula describes the

O. A. Battistel, O. L. Battistel

A general calculational method is applied to investigate symmetry relations among divergent amplitudes in a free fermion model. A very traditional work on this subject is revisited. A systematic study of one, two and three point functions associated to scalar, pseudoscalar, vector and axial-vector densities is performed. The divergent content of the amplitud

Harry W. Braden, Nikita A. Nekrasov

We show that a U(1) instanton on non-commutative R^4 corresponds to a supersymmetric non-singular U(1) gauge field on a commutative Kahler manifold X which is a blowup of C^2 at a finite number of points. For instanton charge k the manifold X can be viewed as a space-time foam. A direct connection with integrable systems of Calogero-Moser type is established

V. G. Gurzadyan

The properties of the Cosmic Microwave Background (CMB) radiation must be different in flat, positively and negatively curved universes. This fact leads to a direct way of determining the geometry of the universe. The signature of the predicted effect of geodesic mixing, i.e., of the `chaotic' behavior of photon beams in negatively curved spaces peculiar to

Rafael Hernandez

We consider non perturbative effects in M-theory compactifications on a seven-manifold of G_2 holonomy arising from membranes wrapped on supersymmetric three-cycles. When membranes are wrapped on associative submanifolds they induce a superpotential that can be calculated using calibrated geometry. This superpotential is also derived from compactification on

E. D. Reese, J. J. Mohr, J. E. Carlstrom, M. Joy

We determine the distances to the z~0.55 galaxy clusters MS 0451.6-0305 and CL 0016+16 from a maximum likelihood joint fit to interferometric Sunyaev-Zel&#39;dovich effect (SZE) and X-ray observations. We model the intracluster medium (ICM) using a spherical isothermal beta-model. We quantify the statistical and systematic uncertainties inherent to these dir

Giulio Biroli, Remi Monasson

The notions of pure states and inherent structures, i.e. stable configurations against 1-spin flip are discussed. We explain why these different concepts accidentally coincide in mean-field models with infinite connectivity and present an exactly solvable unidimensional model where they do not. At zero temperature pure states are to some extent related to k-

Sebastien Descotes, Jan Stern

In the framework of Euclidean QCD on a torus, we study the spectrum of the Dirac operator through inverse moments of its eigenvalues, averaged over topological sets of gluonic configurations. The large-volume dependence of these sums is related to chiral order parameters. We sketch how these results may be applied to lattice simulations in order to investiga

M. J. Bhaseen, I. I. Kogan, O. A. Soloviev, N. Taniguchi

We suggest a procedure for calculating correlation functions of the local densities of states (DOS) at the plateau transitions in the Integer Quantum Hall effect (IQHE). We argue that their correlation functions are appropriately described in terms of the SL($2,{\Bbb C}$)/SU(2) WZNW model (at the usual Ka{\v c}--Moody point and with the level $6 \leq k \leq

Bjorn Andreas, Gottfried Curio

We consider the heterotic string on an elliptic Calabi-Yau three-fold with five-branes wrapping curves in the base (&#39;horizontal&#39; curves) of the Calabi-Yau as well as some elliptic fibers (&#39;vertical&#39; curves). We show that in this generalized set-up, where the association of the heterotic side with the $F$-theory side is changed relative to the

C. O. Lousto

We study the relativistic orbit of binary black holes in systems with small mass ratio. The trajectory of the smaller object (another black hole or a neutron star), represented as a particle, is determined by the geodesic equation on the perturbed massive black hole spacetime. The particle itself generates the gravitational perturbations leading to a problem

Lu-Ming Duan, G. Giedke, J. I. Cirac, P. Zoller

We describe an entanglement purification protocol to generate maximally entangled states with high efficiencies from two-mode squeezed states or from mixed Gaussian continuous entangled states. The protocol relies on a local quantum non-demolition measurement of the total excitation number of several continuous variable entangled pairs. We propose an optical

O. Almaini, A. Lawrence, T. Shanks, A. Edge

We present an analysis of X-ray variability in a flux limited sample of QSOs. Selected from our deep ROSAT survey, these QSOs span a wide range in redshift ($0.1<z<3.2$) and are typically very faint, so we have developed a method to constrain the amplitude of variability in ensembles of low signal-to-noise light curves. We find evidence for trends in this va

Cl. Gabriel, Ph. Spindel

We study, using Rindler coordinates, the quantization of a charged scalar field interacting with a constant, external, electric field. First we establish the expression of the Schwinger vacuum decay rate, using the operator formalism. Then we rederive it in the framework of the Feynman path integral method. Our analysis reinforces the conjecture which identi

R. A. Istomin, A. S. Moskvin

We made use a simplified form for the quantum skyrmion wave function based on the spin coherent states to obtain the analytical expression for appropriate overlap integral.

J. C. Berengut, V. V. Flambaum, G. F. Gribakin

We consider interference effects between p-wave resonance scattering amplitude and background s-wave amplitude in low-energy neutron scattering from a heavy nucleus which goes through the compound nucleus stage. The first effect is in the difference between the forward and backward scattering cross sections. Because of the chaotic nature of the compound stat

Romualdo Pastor-Satorras, Alessandro Vespignani

We present a systematic study of corrections to scaling in the self-organized critical forest-fire model. The analysis of the steady-state condition for the density of trees allows us to pinpoint the presence of these corrections, which take the form of subdominant exponents modifying the standard finite-size scaling form. Applying an extended version of the

Nguyen Tuan Anh

Based on a new theory of causality [1] and its development to the theory of the Universe [2], we show, in this paper, new ideas for building a theory of everything.

L. Ciotti, J. P. Ostriker

Most elliptical galaxies contain central black holes (BHs), and most also contain significant amounts of hot gas capable of accreting on to the central BH due to cooling times short compared to the Hubble time. Why therefore do we not see AGNs at the center of most elliptical galaxies rather than in only (at most) a few per cent of them? We propose here the

Satish D. Joglekar, A. Misra

We consider the question of gauge invariance of the Wilson loop in the light of a new treatment of axial gauge propagator proposed recently based on a finite field-dependent BRS (FFBRS) transformation. We remark that as under the FFBRS transformation the vacuum expectation value of a gauge invariant observable remains unchanged, our prescription automaticall

Alberto Sirlin

We review a number of theoretical developments in Precision Electroweak Physics that are closely connected with the interpretation of experiments. The emphasis is on the test of the Standard Model at the level of its quantum corrections, the search for the Higgs boson, and constraints on new physics.

D. M. Wei, T. Lu

There has been increasing evidence that at least some GRBs are emission beamed. The beamed GRB afterglow evolution has been discussed by several authors in the ultra-relativistic case. It has been shown that the dynamics of the blast wave will be significantly modified by the sideways expansion, and there may be a sharp break in the afterglow light curves un

J. L. Martin, C. R. McKenzie, N. R. Thomas, D. M. Warrington

A radio frequency (RF) transition is used to convert a pure F=2,mF=2 87Rb Bose-Einstein condensate confined in a TOP trap to a mixture of F=2,mF=2 and F=2,mF=1 states. We show that the nature of this coupling process is strongly influenced by the presence of the time varying field of the TOP trap, and complicated by the presence of multiple Zeeman substates.

Wen-Xiu Ma

A theory for constructing integrable couplings of soliton equations is developed by using various perturbations around solutions of perturbed soliton equations being analytic with respect to a small perturbation parameter. Multi-scale perturbations can be taken and thus higher dimensional integrable couplings can be presented. The theory is applied to the Kd

John Hamilton

In [1] it was shown that the Kochen Specker theorem can be written in terms of the non-existence of global elements of a certain varying set over the partially ordered set of boolean subalgebras of projection operators on some Hilbert space. In this paper, we show how obstructions to the construction of such global elements arise, and how this provides a new

B. A. Lysov, O. A. Lysova, O. F. Dorofeyev

Isolated electrons resting near a helium surface have a spectrum close to that of a quantum-defect atom. A precisely solvable model with Rydberg spectrum is sugguested and discussed.

Michele Pavon

The von Neumann collapse of the quantum mechanical wavefunction after a position measurement is derived by a purely probabilistic mechanism in the context of Nelson&#39;s stochastic mechanics.

A. E. Kozhekin, K. Molmer, E. Polzik

We propose an efficient method for mapping and storage of a quantum state of propagating light in atoms. The quantum state of the light pulse is stored in two sublevels of the ground state of a macroscopic atomic ensemble by activating a synchronized Raman coupling between the light and atoms. We discuss applications of the proposal in quantum information pr

LIU Yufeng, HUO Wujun, ZENG Jinyan

The angular momentum structure and energy structure of the coherent state of a 2D isotropic harmonic oscillator were investigated. Calculations showed that the average values of angular momentum and energy (except the zero point energy) of this nonspreading 2D wave packet are identical to those of the corresponding classical oscillator moving along a circula

Antonio-D. Capobianco, Stefano Corrias, Stefano Curtarolo, Carlo G. Someda

Numerical results based on an extended BPM algorithm indicate that, in Marcatili&#39;s lossless tapers and bends, through-flowing waves are drastically different from standing waves. The source of this surprising behavior is inherent in Maxwell&#39;s equations. Indeed, if the magnetic field is correctly derived from the electric one, and the Poynting vector

S. Antoci, L. Mihich

A macroscopic theory for the dynamics of elastic, isotropic matter in presence of electromagnetic fields is proposed here. We avail of Gordon&#39;s general relativistic derivation of Abraham&#39;s electromagnetic energy tensor as starting point. The necessary description of the elastic and of the inertial behaviour of matter is provided through a four dimens

Jens Eggers, Michael P. Brenner

A fluid jet with a finite angular velocity is subject to centripetal forces in addition to surface tension forces. At fixed angular momentum, centripetal forces become large when the radius of the jet goes to zero. We study the possible importance of this observation for the pinching of a jet within a slender jet model. A linear stability analysis shows the

Volker D. Burkert

Recent results on studies of the structure of nucleons and nuclei in the regime of strong interaction QCD are discussed. Use of high current polarized electron beams, polarized targets, and recoil polarimeters, in conjunction with modern spectrometers and detector instrumentation allow much more detailed studies of nucleon and nuclear structure than has been

Maks A. Akivis, Vladislav V. Goldberg

For a four-dimensional (nonisoclinicly geodesic) three-web W (3, 2, 2), a transversal distribution $Δ$ is defined by the torsion tensor of the web. In general, this distribution is not integrable. The authors find necessary and sufficient conditions of its integrability and prove the existence theorem for webs W (3, 2, 2) with integrable distributions $Δ$. T

Stephen J. Montgomery-Smith

This paper gives another version of results due to Raugel and Sell, and similar results due to Moise, Temam and Ziane, that state the following: the solution of the Navier-Stokes equation on a thin 3 dimensional domain with periodic boundary conditions has global regularity, as long as there is some control on the size of the initial data and the forcing ter

Stephen J. Montgomery-Smith

Let (f_n) be a mean zero vector valued martingale sequence. Then there exist vector valued functions (d_n) from [0,1]^n such that int_0^1 d_n(x_1,...,x_n) dx_n = 0 for almost all x_1,...,x_{n-1}, and such that the law of (f_n) is the same as the law of (sum_{k=1}^n d_k(x_1,...,x_k)) . Similar results for tangent sequences and sequences satisfying condition (

Paweł Hitczenko, Stephen Montgomery-Smith

In this note a two sided bound on the tail probability of sums of independent, and either symmetric or nonnegative, random variables is obtained. We utilize a recent result by Latała on bounds on moments of such sums. We also give a new proof of Latała&#39;s result for nonnegative random variables, and improve one of the constants in his inequality.

Paul H. Frampton, T. W. Kephart

We present what we believe is the minimal three-family $AdS/CFT$ model compactified on a nonabelian orbifold $S^{5}/(Q\times Z_{3})$. Nontrivial irreps of the discrete nonabelian group $Q\times Z_{3}$ are identified with the $4$ of $SU(4)$ $R$ symmetry to break all supersymmetries, and the scalar content of the model is sufficient to break the gauge symmetry

Murat Gunaydin, Marco Zagermann

We study the general gaugings of N=2 Maxwell-Einstein supergravity theories (MESGT) in five dimensions, extending and generalizing previous work. The global symmetries of these theories are of the form SU(2)_R X G, where SU(2)_R is the R-symmetry group of the N=2 Poincare superalgebra and G is the group of isometries of the scalar manifold that extend to sym

Marco Cavaglia, Carlo Ungarelli

Vacuum spherically symmetric Einstein gravity in $N\ge 4$ dimensions can be cast in a two-dimensional conformal nonlinear sigma model form by first integrating on the $(N-2)$-dimensional (hyper)sphere and then performing a canonical transformation. The conformal sigma model is described by two fields which are related to the Arnowitt-Deser-Misner mass and to

Y. Brihaye, F. Grard, S. Hoorelbeke

Gravitating t&#39;Hooft-Polyakov magnetic monopoles can be constructed when coupling the Georgi-Glashow model to gravitation. For a given value of the Higgs boson mass, these gravitating solitons exist up to a critical value of the ratio of the vector meson mass to the Planck mass. The critical solution is characterized by a degenerate horizon of the metric.

O. G. Tchikilev

Recursive solution for a general homogeneous in time pure birth branching process with simultaneous production of any number of particles and with continuous evolution parameter is given. Calculational algorithm based on the use of Koenigs function and functional Schroder equation is described. It is shown that multiplicity distributions in e+e- annihilation

B. Mele, S. Petrarca, Soddu

The t->cH decay width has been computed in the standard model with a light Higgs boson. The corresponding branching fraction has been found to be in the range B(t->cH) ~ 10^{-13} - 10^{-14} for M_Z < m_H < 2 M_W. Our results correct the numerical evaluation usually quoted in the literature.

C. A. Garcia Canal, R. Sassot

These lectures include an introduction to the partonic description of the proton, the photon and the `colour singlet&#39;, as seen in inclusive and semi-inclusive DIS, in $e^+e^-$ collisions, and in diffractive processes, respectively. Their formal treatment using structure, fragmentation, and fracture functions is outlined giving an insight into the perturb

Anna Kulesza, W. James Stirling

Double parton scattering, i.e. two parton hard scattering processes in the same hadron-hadron collision, may constitute an important background for Higgs and other new particle searches at the LHC. We point out that like-sign W pair production provides a relatively clean way of searching for, and calibrating, double parton scattering at the LHC.

G. L. Fogli, E. Lisi, D. Montanino, A. Palazzo

We perform an updated phenomenological analysis of the Mikheyev-Smirnov-Wolfenstein (MSW) solutions of the solar neutrino problem, assuming oscillations between two and three neutrino families. The analysis includes the total rates of the Homestake, SAGE, GALLEX, Kamiokande and Super-Kamiokande experiments, as well as the day-night asymmetry and the 18-bin e

C. Greiner, S. Leupold

We show that the nonperturbative quantum transport equations, the `Kadanoff-Baym equations&#39;, can be understood as the ensemble average over stochastic equations of Langevin type. For this we couple a free scalar boson quantum field to an environmental heat bath with some given temperature T. The inherent presence of noise and dissipation related by the f

N M Shumeiko, J G Suarez

The explicit exact expressions of QED lowest-order radiative corrections to the two polarized identical fermion scattering are presented in covariant form. Polarization effects are treated in detail. The infrared divergence from the real photon emission is extracted by covariant approach. Some numerical results for Møller scattering are given.

I. V. Kolokolov, P. V. Vorob&#39;ev, V. V. Ianovski

The possibility of existence of a magnetic monopole has been surveyed by P. Dirac even in 1931, and then from the point of view of the modern theory by A.M. Polyakov and G.~ &#39;tHooft in 1974. Numerous and unsuccessful attempts of experimental search for monopole in cosmic rays and on accelerators in high energy particle collisions have been done. Also the

R. Cantelli, F. Cordero, O. Palumbo, G. Cannelli

Elastic energy absorption measurements versus temperature on semiconducting, semi-insulating (SI) and Fe-doped InP are reported. A thermally activated relaxation process is found only in the SI state, which is identified with the hopping of H atoms trapped at In vacancies. It is proposed that the presence of In vacancies in InP prepared by the liquid encapsu

B. Derrida, S. C. Manrubia, D. H. Zanette

We calculate the probability distribution of repetitions of ancestors in a genealogical tree for simple neutral models of a closed population with sexual reproduction and non-overlapping generations. Each ancestor at generation g in the past has a weight w which is (up to a normalization) the number of times this ancestor appears in the genealogical tree of

M. Bonitz, Th. Bornath, D. Kremp, M. Schlanges

A quantum kinetic theory for correlated charged-particle systems in strong time-dependent electromagnetic fields is developed. Our approach is based on a systematic gauge-invariant nonequilibrium Green&#39;s functions formulation. Extending our previous analysis (Kremp et al., Phys. Rev. E vol. 60, p. 4725 (1999) we concentrate on the selfconsistent treatmen

I. V. Schweigert, V. A. Schweigert, F. M. Peeters

Melting of two dimensional (2D) clusters of classical particles is studied using Brownian dynamics and Langevin molecular dynamics simulations. The particles are confined by a circular hard wall or a parabolic external potential and interact through a dipole or a screened Coulomb potential. We found that with decreasing strength of the inter--particle intera

Mohammad Kohandel, Mehran Kardar

A parallel current can destabilize a single flux line (FL), or an array of FLs. We consider the effects of pinning by point impurities on this instability. The presence of impurities destroys the long-range order of a flux lattice, leading to the so called Bragg glass (BrG) phase. We first show that the long-range topological order of the BrG is also destroy

V. S. Filinov, P. R. Levashov, V. E. Fortov, M. Bonitz

An efficient numerical approach to equilibrium properties of strongly coupled systems which include a subsystem of fermionic quantum particles and a subsystem of classical particles is presented. It uses an improved path integral representation of the many-particle density operator and allows to describe situations of strong coupling and strong degeneracy, w

S. C. Manrubia, A. S. Mikhailov

Very long transients are found in the partially ordered phase of type II of globally coupled logistic maps. The transients always lead the system in this phase to a state with a few synchronous clusters. This transient behaviour is not significantly influenced by the introduction of weak noises. However, such noises generally favor cluster partitions with mo

N. -H. Kwong, M. Bonitz

A nonequilibrium Green&#39;s functions approach to the collective response of correlated Coulomb systems at finite temperature is presented. It is shown that solving Kadanoff-Baym type equations of motion for the two-time correlation functions with the external perturbing field included allows to compute the plasmon spectrum with collision effects in a syste

J. Hofer, T. Schneider, J. M. Singer, M. Willemin

Angular-dependent magnetic torque measurements performed near the critical temperature on single crystals of HgBa_{2}CuO_{4+y}, La_{2-x}Sr{x}CuO_{4}, and YBa_{2}Cu_{3}O_{6.93} are scaled, following the 3D XY model, in order to determine the scaling function dG^{\pm}(z)/dz which describes the universal critical properties near T_{c}. A systematic shift of the

Vasiliki Plerou, Parameswaran Gopikrishnan, Luis. A. Nunes Amaral, Xavier Gabaix

Stock price changes occur through transactions, just as diffusion in physical systems occurs through molecular collisions. We systematically explore this analogy and quantify the relation between trading activity - measured by the number of transactions $N_{Δt}$ - and the price change $G_{Δt}$, for a given stock, over a time interval $[t, t+Δt]$. To this end

M. Grove, P. Lemmens, G. Güntherodt, B. C. Sales

Single crystals of the spin-gap system $\rm (VO)_2P_2O_7$ have been investigated by means of Raman scattering. At temperatures below T=75 K~$\approx 2Δ_{01}({\bf k}=0)$, with $Δ_{01}$ the singlet-triplet gap, a shoulder appears at 47 cm$^{-1}$. An analysis of the polarization selection rules and the temperature dependence of the scattering intensity leads to

V. S. Filinov, M. Bonitz

A numerical approach is presented which allows to calculate the equilibrium properties of Fermi systems which are both, strongly coupled and strongly degenerate. Based on a novel path integral representation of the many-particle density operator, quantum and spin effects are included. As an illustration, results for the pressure and energy of an electron-pro

S. K. Kwon, B. I. Min

To explore the origin of the observed giant magnetic moments ($\sim 7 μ_B$) of Fe impurities on the surface and in the bulk of Cs films, we have performed the relativistic LSDA + U calculations using the linearized muffin-tin orbital (LMTO) band method. We have found that Fe impurities in Cs behave differently from those in noble metals or in Pd. Whereas the

M. Abel, L. Biferale, M. Cencini, M. Falcioni

An efficient approach to the calculation of the $ε$-entropy is proposed. The method is based on the idea of looking at the information content of a string of data, by analyzing the signal only at the instants when the fluctuations are larger than a certain threshold $ε$, i.e., by looking at the exit-time statistics. The practical and theoretical advantages o