February 1999 arXiv papers — page 3

Philip A. E. Jonkers, Steven J. Pickering, Hans De Raedt, Gen Tatara

The effect of impurity and domain-wall scattering on the electrical conductivity of disordered mesoscopic magnetic thin films is studied by use of computer simulation. The results indicate a reduction of resistivity due to a domain wall, which is consistent with the explanation in terms of the dephasing caused by domain wall.

G. Manoj, P. Ray

We reply to the comment cond-mat/9902073 by Ben-Naim and Krapivsky on our paper cond-mat/9901130. We show that their arguments are incorrect, and present more numerical results to back our earlier conclusions.

Andrea Pagnani

The one dimensional direct polymer in random media model is investigated using a variational approach in the replica space. We demonstrate numerically that the stable point is a maximum and the corresponding statistical properties for the delta correlated potential are in good agreements with the known analytic solution. In the case of power-law correlated p

R. Kajimoto, H. Yoshizawa, H. Kawano, H. Kuwahara

In order to study the magnetic and crystal structures in the Nd{1-x}Sr{x}MnO{3} system, we have peformed neutron diffraction measurements on melt-grown polycrystalline samples with 0.49 < x < 0.75. As a function of hole concentration x, the system shows systematic transformation of magnetic and crystal structures, which is consistently explained by the chang

C. J. Bolton-Heaton, C. J. Lambert, Vladimir I. Falko, V. Prigodin

The dynamics of electronic tunneling through a disordered 1D chain of finite length is considered. We calculate distributions of the transmission coefficient T, Wigner delay time and, $τ_ϕ$ and the transport time, $τ_t=Tτ_ϕ$. The central bodies of these distributions have a power-law form, what can be understood in terms of the resonant tunneling through loc

K. Behnia, C. Capan, D. Mailly, B. Etienne

Using an array of miniature Hall probes, we monitored the spatiotemporal variation of the internal magnetic induction in a superconducting niobium sample during a slow sweep of external magnetic field. We found that a sizable fraction of the increase in the local vortex population occurs in abrupt jumps. The size distribution of these avalanches presents a p

J. Chihara, Y. Ueshima, S. Kiyokawa

We extend the quantal hypernetted-chain (QHNC) method, which has been proved to yield accurate results for liquid metals, to treat a partially ionized plasma. In a plasma, the electrons change from a quantum to a classical fluid gradually with increasing temperature; the QHNC method applied to the electron gas is in fact able to provide the electron-electron

F. Rojas, A. D. Rutenberg

To sensitively test scaling in the 2D XY model quenched from high-temperatures into the ordered phase, we study the difference between measured correlations and the (scaling) results of a Gaussian-closure approximation. We also directly compare various length-scales. All of our results are consistent with dynamical scaling and an asymptotic growth law $L \si

M. A. Despósito, A. Villares Ferrer, A. O. Caldeira, A. H. Castro Neto

We have studied the problem of the dissipative motion of Bloch walls considering a totally anisotropic one dimensional spin chain in the presence of a magnetic field. Using the so-called &#34;collective coordinate method&#34; we construct an effective Hamiltonian for the Bloch wall coupled to the magnetic excitations of the system. It allows us to analyze th

A. Awazu

A cellular automaton named Rule 184++C is proposed as a meta-model to investigate the flow of various complex particles. In this model, unlike the granular pipe flow and the traffic flow, not only the free-jam phase transition but also the free-intermediate, the intermediate-jam, and the dilute-dense phase transitions appear. Moreover, the freezing phenomena

T. X. Thuan, Y. I. Izotov

We develop here the theme that extremely metal-deficient Blue Compact Dwarf Galaxies (BCDs), those with Z < Zsun/20, are young galaxies which did not start to form stars until ~ 100 Myr ago. They can be thus considered as primeval galaxies in our local volume of the universe, and are excellent laboratories for studying physical processes occuring at the time

V. A. Lipovetsky, F. H. Chaffee, Y. I. Izotov, C. B. Foltz

We present Multiple Mirror Telescope (MMT) and Keck II telescope spectrophotometry and 3.5m Calar Alto telescope R, I photometry of the western component of the extremely low-metallicity blue compact galaxy SBS 0335-052. The components, separated by 22 kpc, appear to be members of a unique, physically connected system. It is shown that SBS 0335-052W consists

P. Meszaros, M. J. Rees

The prompt $(t \siml 0.16$ days) light curve and initial 9-th magnitude optical flash from GRB 990123 can be attributed to a reverse external shock, or possibly to internal shocks. We discuss the time decay laws and spectral slopes expected under various dynamical regimes, and discuss the constraints imposed on the model by the observations, arguing that the

S. Veilleux, J. Bland-Hawthorn, G. Cecil, R. B. Tully

The Hawaii Imaging Fabry-Perot Interferometer (HIFI) on the University of Hawaii 2.2m telescope was used to map the Halpha and [O III] 5007 A emission-line profiles across the entire disk of the edge-on Sb galaxy NGC 4388. We confirm a rich complex of highly ionized gas that extends ~4 kpc above the disk of this galaxy. Low-ionization gas associated with sta

Thibaut Lery, J. Heyvaerts, S. Appl, C. A. Norman

A simplified model for the stationary, axisymmetric structure of magnetized winds with a polytropic equation of state is presented. The shape of the magnetic surfaces is assumed to be known (conical in this paper) within the fast magnetosonic surface. The model is non-self-similar. The regularity of the magnetic surfaces at critical surfaces is ensured by th

R. Y. Shuping, T. P. Snow, R. Crutcher, B. L. Lutz

The H II region W40 harbors a small group of young, hot stars behind roughly 9 magnitudes of visual extinction. We have detected gaseous carbon monoxide (CO) and diatomic carbon (C_2) in absorption toward the star W40 IRS 1a. The 2-0 R0, R1, and R2 lines of 12CO at 2.3 micron were measured using the CSHELL on the NASA IR Telescope Facility (with upper limits

Thibaut Lery, Richard N. Henriksen, Jason D. Fiege

We study a self-similar circulation model for protostellar bipolar outflows. The model is axisymmetric and stationary, and now includes Poynting flux. Compared to an earlier version of the model, this addition produces faster and more collimated outflows. Moreover the luminosity needed for the radiative heating is smaller. The model has been applied to both

Erik Kuulkers, R. P. Fender, Ralph E. Spencer, Richard J. Davis

The well-known black-hole X-ray transient A0620-00 was a bright radio source during the first part of its outburst in 1975. We have revisited the available data and find for the first time evidence that the source exhibited multiple jet ejections. Rapid radio spectral changes indicate the addition of at least three new components which are initially opticall

Donatella Romano

We study the temporal evolution of the 7Li abundance in the gaseous medium for all the components (halo, disk and bulge) of our Galaxy. We adopt nucleosynthesis prescriptions on stellar lithium production based upon recent observational results and up-to-date theoretical considerations in the framework of a fully consistent chemical evolution model. 7Li prod

Danny Steeghs, Rudolf Stehle

We use the grid of hydrodynamic accretion disc calculations of Stehle (1999) to construct orbital phase dependent emission line profiles of thin discs carrying spiral density waves. The observational signatures of spiral waves are explored to establish the feasibility of detecting spiral waves in cataclysmic variable discs using prominent emission lines in t

Jordi Jose, Alain Coc, Margarita Hernanz

Classical novae eject significant amounts of nuclear processed material into the interstellar medium. Among the isotopes synthesized during such explosions, two radioactive nuclei deserve a particular attention: 22Na and 26Al. In this paper, we investigate the nuclear paths leading to 22Na and 26Al production during nova outbursts by means of an implicit, hy

B. T. Draine, A. Lazarian

Observations of the cosmic microwave background have revealed a component of 10-60 GHz emission from the Galaxy which correlates with 100-140um emission from interstellar dust but has an intensity much greater than expected for the low-frequency tail of the &#34;electric dipole vibrational&#34; emission peaking at \~130um. This &#34;anomalous emission&#34; i

Mark Cropper, Kinwah Wu, Gavin Ramsay, Aysegul Kocabiyik

We have calculated the temperature and density structure of the hot postshock plasma in magnetically confined accretion flows, including the gravitational potential. This avoids the inconsistency of previous calculations which assume that the height of the shock is negligible. We assume a stratified accretion column with 1-d flow along the symmetry axis. We

Y. -S. Park, J. Kim, Y. C. Minh

The HCN 1-0 hyperfine lines have been observed toward 24 young stellar objects (YSOs) of class 0 and I. We examined how their line shapes and velocity shifts vary along with their relative optical depths and compared them with those of CS 2-1, H2CO 2(12)-1(11), and HCO+ 4-3 & 3-2 transitions previously observed by Mardones et al. (1997) and Gregersen et al.

Eiichiro Komatsu, Tetsu Kitayama, Yasushi Suto, Makoto Hattori

We report on the detection of the Sunyaev -- Zel&#39;dovich (SZ) signals toward the most luminous X-ray cluster RXJ1347-1145 at Nobeyama Radio Observatory (21 and 43 GHz) and at James Clerk Maxwell Telescope (350 GHz). In particular the latter is the first successful detection of the SZ temperature increment in the submillimeter band which resolved the profi

Kim-Vy H. Tran, Daniel D. Kelson, Pieter van Dokkum, Marijn Franx

We present results from a dynamical study of the high redshift, massive, X-ray luminous galaxy cluster MS1054--03. We significantly increase the number of confirmed cluster members by adding 20 to an existing set of twelve; using the confirmed members, we estimate MS1054--03&#39;s redshift, velocity dispersion, and mass. We find that z=0.8329 +/- 0.0017, sig

Joanne C. Baker, Richard W. Hunstead, Vijay K. Kapahi, C. R. Subrahmanya

Optical spectroscopic data are presented here for quasars from the Molonglo Quasar Sample (MQS), which forms part of a complete survey of 1-Jy radio sources from the Molonglo Reference Catalogue. The combination of low-frequency selection and complete identifications means that the MQS is relatively free from the orientation biases which affect most other qu

P. J. McCarthy, L. Yan, W. Freudling, H. Teplitz

We present the first results of a survey of random fields with the slitless G141 ($λ_c = 1.5μ, Δλ=0.8μ$) grism on NICMOS. Approximately 64 square arcminutes have been observed at intermediate and high galactic latitudes. The 3$σ$ limiting line and continuum fluxes in each field vary from $7.5 \times 10^{-17}$ to $1 \times 10^{-17} erg/cm^2/sec$ and from H =

Igor Pesando

We compute the effective potential of a system composed by a Dp brane and a separated anti-Dp brane at tree level in string theory. We show explicitly that the tachyon condenses and that the scalars which describe transverse fluctuations acquire a VEV proportional to the distance.

Michael Bershadsky, Slava Zhukov, Arkady Vaintrob

We discuss the sigma model on the $PSL(n|n)$ supergroup manifold. We demonstrate that this theory is exactly conformal. The chiral algebra of this model is given by some extension of the Virasoro algebra, similar to the $W$ algebra of Zamolodchikov. We also show that all group invariant correlation functions are coupling constant independent and can be compu

Lior M. Burko

We analyze radiation reaction for synchrotron radiation by computing, via a multipole expansion, the near field evaluated on the world-line of the charge. We find that the temporal component of the self four-force agrees with the radiated power, which one calculates in the radiation zone. This is the case for each mode in the multipole decomposition. We also

Elihu Boldt, Pranab Ghosh

Considerations of the collision losses for protons traversing the 2.7 K black body microwave radiation field have led to the conclusion that the highest energy cosmic rays, those observed at $\geq 10^{20}$ eV, must come from sources within the present epoch. In light of this constraint, it is here suggested that these particles may be accelerated near the ev

A. Hart, M. Teper

We extend our previous study of magnetic monopole currents in the maximally Abelian gauge [hep-lat/9712003] to larger lattices at small lattice spacings (20^4 at beta = 2.5 and 32^4 at beta = 2.5115). We confirm that at these weak couplings there continues to be one monopole cluster that is very much longer than the rest and that the string tension, K, is en

Dongsu Bak, Soo-Jong Rey

A new version of holographic principle for cosmology is proposed, which dictates that particle entropy within `cosmological apparent horizon&#39; should not exceed gravitational entropy associated with the apparent horizon. It is shown that, in the Friedman-Robertson-Walker (FRW) cosmology, the open Universe as well as a restricted class of flat cases are co

M. Calixto, V. Aldaya

New clues for the best understanding of the nature of the symmetry-breaking mechanism are revealed in this paper. A revision of the standard gauge transformation properties of Yang-Mills fields, according to a group approach to quantization scheme, enables the gauge group coordinates to acquire dynamical content outside the null mass shell. The corresponding

A. Yildiz

The braided Hopf algebra structure of the generalized oscillator is investigated. Using the solutions two types of braided Fibonacci oscillators are introduced. This leads to two types of braided Biedenharn-Macfarlane oscillators.

C. Mertz, C. Vellidis, R. Alarcon, D. H. Barkhuff

High-precision H(e,e&#39;p)pi0 measurements at Q2=0.126 (GeV/c)2 are reported, which allow the determination of quadrupole amplitudes in the gamma* N->Delta transition; they simultaneously test the reliability of electroproduction models. The derived quadrupole-to-dipole amplitude ratios, Rsm=(-6.5 +- 0.2{stat+sys} +- 2.5{mod}) % and Rem=(-2.1 +- 0.2{stat+sy

Satoru Muto, Hideo Aoki

Crystallization of a classical two-dimensional one-component plasma (electrons interacting with the Coulomb repulsion in a uniform neutralizing positive background) is investigated with a molecular dynamics simulation. The positional and the orientational correlation functions are calculated for the first time. We have found an indication that the solid phas

Somshubhro Bandyopadhyay, Guruprasad Kar

We study broadcasting of entanglement where we use universal quantum cloners (in general less optimal) to perform local cloning operations. We show that there is a lower bound on the fidelity of the universal quantum cloners that can be used for broadcasting. We prove that an entanglement is optimally broadcast only when optimal quantum cloners are used for

M. T. Peña, D. O. Riska, A. Stadler

The role of the low lying nucleon resonances beyond the $Δ(1232)$ in the reaction $pp\to ppπ^0$ near threshold is shown to be numerically significant by a calculation, which takes into account the pion re-scattering contribution described by chiral perturbation theory and the short-range mechanisms that are implied by the nucleon-nucleon interaction model. T

Andrew Chamblin, Roberto Emparan, Clifford V. Johnson, Robert C. Myers

We compute the properties of a class of charged black holes in anti-de Sitter space-time, in diverse dimensions. These black holes are solutions of consistent Einstein-Maxwell truncations of gauged supergravities, which are shown to arise from the inclusion of rotation in the transverse space. We uncover rich thermodynamic phase structures for these systems,

Eckehard W. Mielke, Alfredo Macias

Similarily as in the Ashtekar approach, the translational Chern-Simons term is, as a generating function, instrumental for a chiral reformulation of simple (N=1) supergravity. After applying the algebraic Cartan relation between spin and torsion, the resulting canonical transformation induces not only decomposition of the gravitational fields into selfdual a

Oren Bergman, Eric G. Gimon, Petr Horava

Using the relation between D-brane charges and K-theory, we study non-BPS D-branes and their behavior under T-duality. We point out that in general compactifications, D-brane charges are classified by relative K-theory groups. T-duality is found to act as a symmetry between the relative K-theory groups in Type II and Type I/IA theories. We also study Type \t

J. Iglesias-Paramo, J. M. Vilchez

We present the results of the study of the Star Formation Rates (SFRs) of a sample of disk galaxies in nearby compact groups compared with the SFRs of a sample of field galaxies. For this purpose, H$\alpha$ luminosities and equivalent widths were derived for the galaxies of our sample. A direct comparison of the equivalent widths and H$\alpha$ luminosities n

V. Kidambi, A. Widom, C. Lerner, Y. N. Srivastava

We consider a photon beam incident on a stack of polarizers as an example of a von Neumann projective measurement, theoretically leading to the quantum Zeno effect. The Maxwell theory (which is equivalent to the single photon Schrödinger equation) describes measured polarization phenomena, but without recourse to the notion of a projective measurement.

Vladimir I. Man&#39;ko

The tomographic invertable map of the Wigner function onto the positive probability distribution function is studied. Alternatives to the Schrödinger evolution equation and to the energy level equation written for the positive probability distribution are discussed. Instead of the transition probability amplitude (Feynman path integral) a transition probabil

M. Havukainen, G. Drobny, S. Stenholm, V. Buzek

We show how two level atoms can be used to build microscopic models for mirrors and beamsplitters. The mirrors can have arbitrary shape allowing closed cavities to be built. It is possible to build networks or mirrors and beamsplitters and follow the time-evolution of the intensity of the radiation through the system.

Vittorio Giovannetti, Paolo Tombesi, David Vitali

We solve exactly the non-Markovian dynamics of a cavity mode in the presence of a feedback loop based on homodyne measurements, in the case of a non-zero feedback delay time. With an appropriate choice of the feedback parameters, this scheme is able to significantly increase the decoherence time of the cavity mode, even for delay times not much smaller than

Michael Fleischhauer

Spontaneous emission and Lamb shift of atoms in absorbing dielectrics are discussed. A Green&#39;s-function approach is used based on the multipolar interaction Hamiltonian of a collection of atomic dipoles with the quantised radiation field. The rate of decay and level shifts are determined by the retarded Green&#39;s-function of the interacting electric di

Vladimir Man&#39;ko, Marcos Moshinsky, Anju Sharma

Long ago appeared a discussion in quantum mechanics of the problem of opening a completely absorbing shutter on which were impinging a stream of particles of definite velocity. The solution of the problem was obtained in a form entirely analogous to the optical one of diffraction by a straight edge. The argument of the Fresnel integrals was though time depen

H. Mitter, D. Robaschik

A complete thermodynamic treatment of the Casimir effect is presented. Explicit expressions for the free and the internal energy, the entropy and the pressure are discussed. As an example we consider the Casimir effect with different temperatures between the plates ($T$) resp. outside of them ($T&#39;$). For $T&#39;<T$ the pressure of heat radiation can even

T. Shigehara, H. Mizoguchi, T. Mishima, Taksu Cheon

We propose a new method to construct a four parameter family of quantum-mechanical point interactions in one dimension, which is known as all possible self-adjoint extensions of the symmetric operator $T=-Δ\lceil C^{\infty}_{0}({\bf R} \backslash\{0\})$. It is achieved in the small distance limit of equally spaced three neighboring Dirac&#39;s $δ$ potentials

L. F. Santos, C. O. Escobar

We extend the beable interpretation, due to Bell, to the continuous spontaneous localization model (CSL). Results obtained by Vink are generalized to the modified Schrodinger equation of Ghirardi, Pearle and Rimini (GPR), which allows a beable interpretation for position and momentum.

Rudolf Grimm, Matthias Weidemüller, Yurii B. Ovchinnikov

The subject of this review are atom traps based on optical dipole forces in laser fields, along with their unique features as storage devices at ultralow energies. The basic physics of the dipole interaction is discussed, and the experimental background of dipole trapping experiments is explained. Specific trapping schemes and experiments are presented, wher

Itai Cohen, Michael P. Brenner, Jens Eggers, Sidney R. Nagel

We address the dynamics of a drop with viscosity $λη$ breaking up inside another fluid of viscosity $η$. For $λ=1$, a scaling theory predicts the time evolution of the drop shape near the point of snap-off which is in excellent agreement with experiment and previous simulations of Lister and Stone. We also investigate the $λ$ dependence of the shape and brea

Walter Dittrich

We consider the two-dimensional non-relativistic Coulomb problem with the aid of the momentum space construction of the associated Green&#39;s function. Our presentation has precursors in three dimensions. It is mainly Schwinger&#39;s approach which we advocate and project onto two dimensions.

Brian K. Davis

The symmetric distribution and all other states in the symmetry sector of the frequency trajectory increase mean fitness during competitive replication at sublinear propagation rates (parabolic time course). States in the non-symmetry sector, by contrast, produce negative time variations in mean fitness. The polymorphic steady state attained in sublinear sys

Kaoru Yokoya

A new algorithm for calculating the spin tune and the n-axis for circular accelerators is presented. The method resembles the one employed in the existing program code SODOM in that one-turn numerical spin maps at equally spaced orbit angle variables are used but it is more efficient than the latter. Furthermore, it is applicable at large openning angles of

T. Barnes, N. Black, D. J. Dean, E. S. Swanson

In this paper we derive quark model results for scattering amplitudes and equivalent low energy potentials for heavy meson pairs, in which each meson contains a heavy quark. This &#34;BB&#34; system is an attractive theoretical laboratory for the study of the nuclear force between color singlets; the hadronic system is relatively simple, and there are lattic

D. J. Dean, S. E. Koonin

We develop a shell-model Monte Carlo (SMMC) method to calculate densities of states with varying exciton (particle-hole) number. We then apply this method to the doubly closed-shell nucleus 40Ca in a full 0s-1d-0f-1p shell-model space and compare our results to those found using approximate analytic expressions for the partial densities. We find that the eff

Berndt Muller

I review Klaus Kinder-Geiger&#39;s contributions to the physics of relativistic heavy ion collisions, in particular, the Parton Cascade Model. Klaus developed this model in order to provide a QCD-based description of nucleus-nucleus reactions at high energies such as they will soon become available at the Brookhaven Relativistic Heavy Ion Collider. The PCM d

Silviu Olariu, Agata Olariu

We have calculated integrated cross sections from tabulated nuclear data for two-photon transitions in 178-Hf, summed over all lower states which are possible for a given pair of initial and intermediate states. These processes are of interest for the problem of induced gamma emission. The largest integrated cross section found among 24 two-photon processes

Dirk Schlingemann

Several two-dimensional quantum field theory models have more than one vacuum state. Familiar examples are the Sine-Gordon and the $ϕ^4_2$-model. It is known that in these models there are also states, called kink states, which interpolate different vacua. A general construction scheme for kink states in the framework of algebraic quantum field theory is dev

Hans Plesner Jakobsen, Hechun Zhang

A natural family of quantized matrix algebras is introduced. It includes the two best studied such. Located inside ${\s U}_q(A_{2n-1})$, it consists of quadratic algebras with the same Hilbert series as polynomials in $n^2$ variables. We discuss their general properties and investigate some members of the family in great detail with respect to associated var

M. Daniel, P. Kirk

We derive a decomposition formula for the spectral flow of a 1-parameter family of self-adjoint Dirac operators on an odd-dimensional manifold $M$ split along a hypersurface $Σ$ ($M=X\cup_Σ Y$). No transversality or stretching hypotheses are assumed and the boundary conditions can be chosen arbitrarily. The formula takes the form $SF(D)= SF(D_{|X}, B_X) + SF

Maks A. Akivis, Vladislav V. Goldberg

The authors study the geometry of lightlike hypersurfaces on a four-dimensional manifold $(M, c)$ endowed with a pseudoconformal structure $c = CO (2, 2)$. They prove that a lightlike hypersurface $V \subset (M, c)$ bears a foliation formed by conformally invariant isotropic geodesics and two isotropic distributions tangent to these geodesics, and that these

Atsushi Nakayashiki

The trace of intertwining operators over the level one irreducible highest weight modules of the quantum affine algebra of type A_{N-1} is studied. It is proved that the trace function gives a basis of the solution space of the qKZ equation at a generic level. The highest-highest matrix element of the composition of intertwining operators is explicitly calcu

M. Bialy

We study the inviscid Burgers equation in the presence of spatially periodic potential force. We prove that for foliated initial value problem there are always solutions developing shocks in a finite time. We give an application of this result to a quasi-linear system of conservation laws which appeared in the study of integrable Hamiltonian systems with 1.5

F. Laytimi, W. Nahm

For ample vector bundles $E$ over compact complex varieties $X$ and a Schur functor $S_I$ corresponding to an arbitrary partition $I$ of the integer $|I|$, one would like to know the optimal vanishing theorem for the cohomology groups $H^{p,q}(X, S_I(E))$, depending on the rank of $E$ and the dimension $n$ of $X$. Three years ago (Nov. 1995), in an unpublish

Oliver DeWolfe, Amihay Hanany, Amer Iqbal, Emanuel Katz

We generalize the (p,q) 5-brane web construction of five-dimensional field theories by introducing (p,q) 7-branes, and apply this construction to theories with a one-dimensional Coulomb branch. The 7-branes render the exceptional global symmetry of these theories manifest. Additionally, 7-branes allow the construction of all E_n theories up to n=8, previousl

J. N. Acosta, N. Berkovits, O. Chandia

We write the BRST operator of the N=1 superstring as $Q= e^{-R} (\oint dz γ^2 b)e^R$ where $γ$ and $b$ are super-reparameterization ghosts. This provides a trivial proof that $Q$ is nilpotent.

A. Abdurrahman, J. Bordes

In is shown explicitly that the Witten&#39;s interaction 3-vertex is a solution to the comma overlap equations; hence establishing the equivalence between the conventional and the &#34;comma&#34; formulation of interacting string theory at the level of vertices.

Abdulmajeed Abdurrahman, Jose Bordes, Cristobal Lara

An algebraic proof of the Gluing Theorem at tree level of perturbation theory in String Field Theory is given. Some applications of the theorem to closed string non-polynomial action are briefly discussed

J. Manjavidze

The fields nonlinear modes quantization scheme is discussed. New form of the perturbation theory achieved by unitary mapping the quantum dynamics in the space $W_G$ of (action, angle)-type collective variables. It is shown why the transformed perturbation theory contributions may accumulated exactly on the boundary $\pa W_G$. Abilities of the developed forma

Peter. C. Tandy

Within the Dyson-Schwinger equation approach to modeling QCD for meson physics, we present new results for $g_{ρππ}$ and the coupling constants and form factors for the transitions $γ^\ast πρ$ and $γ^\ast π^0 γ$. We discuss the role of the sub-dominant covariants of the $π$ Bethe-Salpeter amplitude and investigate the asymptotic behavior of the $γ^\ast π^0 γ

M. Aw, M. K. Banerjee, H. Forkel

We calculate the leading direct-instanton contributions to the operator product expansion of the nucleon correlator in a magnetic background field and set up improved QCD sum rules for the nucleon magnetic moments. Remarkably, the instanton contributions are found to affect only those sum rules which had previously been considered unstable. The new sum rules

Jusak Tandean

We estimate the CP-violating rate asymmetry for the decay Omega^- -> Cascade + pion. Within the standard model, we find that it could be as large as 2 x 10^(-5). This is significantly larger than the corresponding rate asymmetries for other non-leptonic hyperon decays, which are typically less than 10^(-6).

M. Bordag, B. Geyer, G. L. Klimchitskaya, V. M. Mostepanenko

We consider the Casimir force including all important corrections to it for the configuration used in a recent experiment employing an atomic force microscope. We calculate the long-range hypothetical forces due to the exchange of light and massless elementary particles between the atoms constituting the bodies used in the experiment --- a dielectric plate a

N. G. Antoniou, Y. F. Contoyiannis, F. K. Diakonos

A critical point of second order, belonging to the universality class of the 3d Ising model, has recently been advocated as a strong candidate for the critical behaviour (at high temperatures) of QCD with non-zero quark masses. The implications of this conjecture are investigated in the multiparticle environment of high-energy collisions. A universal intermi

M. Tsypin

We study the properties of the electroweak theory in the vicinity of the critical point --- the endpoint of the first order phase transition line that exists in a wide class of theories, including the Standard Model and a part of the parameter space of the Minimal Supersymmetric Standard Model. We find that the critical point belongs to the 3d Ising universa

Andrzej Wodecki, Wieslaw A. Kaminski, Fedor Simkovic

We analyze the contributions to the neutrinoless double $β$ decay ($0νββ$-decay) coming from the Grand Unified Theory (GUT) constrained Minimal Supersymmetric Standard Model (MSSM) with trilinear R-parity breaking. We discuss the importance of two-nucleon and pion-exchange realizations of the quark-level $0νββ$-decay transitions. In this context, the questio

Dmitri Bardin, Martin Grunewald, Giampiero Passarino

The complete list of definitions for quantities relevant in the analysis of SLD/LEP-1 results around the Z-resonance is given. The common set of conventions adopted by the programs TOPAZ0 and ZFITTER, following the recommendations of the LEP electroweak working group, is reviewed. The relevance of precision calculations is discussed in detail both for pseudo

M. V. Polyakov, C. Weiss

We study the non-forward matrix elements of twist-2 QCD light-ray operators and their representations in terms of skewed and double distributions, considering the pion as well as the nucleon. We point out the importance of explicitly including all twist-2 structures in the double distribution representation, which naturally leads to a ``two-component&#39;&#3

ALEPH Collaboration, R. Barate et al

Data collected at centre-of-mass energies of 181-184 GeV by ALEPH at LEP corresponding to an integrated luminosity of 56.9 pb-1, are analysed in a search for pair-produced charged Higgs bosons H+-. Three analyses are employed to select the tau^+ nu_tau tau^- nubar_tau, c sbar tau^- nubar_tau/ cbar s tau^+ nu_tau and c sbar s cbar final states. No evidence fo

Saro Ong

We reexamine the feasibility of two-photon reactions at DA$Φ$NE with the KLOE detector excluding the small angle tagging system. Event-rate predictions of interesting channels : $γγ\to π^0, η$ and $γγ\to π^+ π^-, π^0 π^0$ are discussed.

L. C. Garcia de Andrade

Vacuumless defects in space-times with torsion may be obtained from vacuum defects in spacetimes without torsion.This idea is applied to planar domain walls and global monopoles.In the case of domain walls exponentially decaying Higgs type potentials are obtained.In the case of global monopoles torsion string type singularities are obtained like the string s

J. M. Nester, H-J Yo

General relativity can be presented in terms of other geometries besides Riemannian. In particular, teleparallel geometry (i.e., curvature vanishes) has some advantages, especially concerning energy-momentum localization and its ``translational gauge theory&#39;&#39; nature. The standard version is metric compatible, with torsion representing the gravitation

M. Dineykhan, R. G. Nazmitdinov

Crossings between spin-singlet and spin-triplet lowest states are analyzed within the model of a two-electron quantum dot in a perpendicular magnetic field. The explicit expressions in terms of the magnetic field, the magnetic quantum number $m$ of the state and the dimensionless dot size for these crossings are found.

Robert S. Whitney, Igor V. Lerner, Robert A. Smith

We attempt to systematically derive perturbative quantum corrections to the Berry diagonal approximation of the two-level correlation function (TLCF) for chaotic systems. To this end, we develop a ``weak diagonal approximation&#39;&#39; based on a recent description of the first weak localisation correction to conductance in terms of the Gutzwiller trace for

Th. Pillo, J. Hayoz, H. Berger, M. Grioni

We report high resolution angle-scanned photoemission and Fermi surface (FS) mapping experiments on the layered transition-metal dichalcogenide 1T-TaS_2 in the quasi commensurate (QC) and the commensurate (C) charge-density-wave (CDW) phase. Instead of a nesting induced partially removed FS in the CDW phase we find a pseudogap over large portions of the FS.

P. Butera, M. Comi

High temperature series expansions of the spin-spin correlation function for the XY (or plane rotator) model on the triangular lattice are extended by two terms up to order beta^{14}. Tables of the expansion coefficients are reported for the correlation function spherical moments of order l=0 and 2. Our analysis of the series supports the Kosterlitz-Thouless

R. D. Coalson, A. Duncan, S. Tsonchev

The lattice field theory approach to the statistical mechanics of a classical Coulomb gas [R. Coalson and A. Duncan, J. Chem. Phys. 97,5653(1992)] is generalized to include charged polymer chains. Saddle-point analysis is done on the functional integral representing the partition function of the full system. Mean-field level analysis requires extremization o

J. Ruostekoski

We theoretically study the propagation of light in a Fermi-Dirac gas in the presence of a superfluid state. BCS pairing between atoms in different hyperfine levels may significantly increase the optical linewidth and line shift of a quantum degenerate Fermi-Dirac gas and introduce a local-field correction that, under certain conditions, dramatically dominate

L. Trappeniers, J. Vanacken, L. Weckhuysen, K. Rosseel

We have studied the influence of columnar defects, created by heavy-ion (Kr) irradiation with doses up to 6 10^11 Kr-ions/cm2, on the superconducting critical parameters of single crystalline (YxTm1-x)Ba2Cu3O7. Magnetisation measurements in pulsed fields up to 50 T in the temperature range 4.2 - 90 K revealed that: (i) in fields up to T the critical current

S. N. Evangelou, J. -L. Pichard

We study the quasiperiodic Harper&#39;s model in order to give further support for a possible universality of the critical spectral statistics. At the mobility edge we numerically obtain a scale-invariant distribution of the bands $S$, which is closely described by a semi-Poisson $P(S)=4S \exp(-2S)$ curve. The $\exp (-2S)$ tail appears when the mobility edge

Markus Buttiker, Andrew M. Martin

The dephasing time in coupled mesoscopic conductors is caused by the fluctuations of the dipolar charge permitted by the long range Coulomb interaction. We relate the phase breaking time to elementary transport coefficients which describe the dynamics of this dipole: the capacitance, an equilibrium charge relaxation resistance and in the presence of transpor

Emilio Hernandez-Garcia, Miguel Hoyuelos, Pere Colet, Raul Montagne

We study the spatiotemporal dynamics, in one and two spatial dimensions, of two complex fields which are the two components of a vector field satisfying a vector form of the complex Ginzburg-Landau equation. We find synchronization and generalized synchronization of the spatiotemporally chaotic dynamics. The two kinds of synchronization can coexist simultane

Makoto Kishimoto

The HST archival UV imaging polarimetry data of NGC 1068 is re-examined. Through an extensive estimation of the observational errors, we discuss whether the distribution of the position angles (PAs) of polarization is simply centrosymmetric or not. Taking into account the effect of a bad focus at the time of the observation, we conclude that, within the accu

D. T. Jaffe, J. Martin-Pintado

We have observed seven ultracompact HII regions in hydrogen recombination lines in the millimeter band. Toward four of these regions, there is a high velocity (full width to half maximum 60-80 km/s) component in the line profiles. The high velocity gas accounts for 35-70% of the emission measure within the beam. We compare these objects to an additional seve

G. S. Bisnovatyi-Kogan, R. V. E. Lovelace

Recent papers discussing advection dominated accretion flows (ADAF) as a solution for astrophysical accretion problems should be treated with some caution because of their uncertain physical basis. The suggestions underlying ADAF involve ignoring the magnetic field reconnection in heating of the plasma flow, assuming electron heating due only to binary Coulo