July 2000 arXiv papers — page 11

V. Ts. Gurovich, H. -J. Schmidt, I. V. Tokareva

The evolution of the closed Friedmann Universe with a packet of short scalar waves is considered with the help of the Wheeler--DeWitt equation. The packet ensures conservation of homogeneity and isotropy of the metric on average. It is shown that during tunneling the amplitudes of short waves of a scalar field can increase catastrophically promptly if their

Wojciech Florek

The group-theoretical classification of trion states is presented. It is based on considerations of products of irreducible representations of the 2D translation group. For a given BvK period N degeneracy of obtained states is N^2. Trions consist of two identical particles so the symmetrization of states with respect to particles transposition is considered.

A. C. C. Coolen, J. van Mourik

We propose a general quantitative scheme in which systems are given the freedom to sacrifice energy equi-partitioning on the relevant time-scales of observation, and have phase transitions by separating autonomously into ergodic sub-systems (clusters) with different characteristic time-scales and temperatures. The details of the break-up follow uniquely from

A. V. Zvelindovsky, G. J. A. Sevink, J. G. E. M. Fraaije

The first three-dimensional simulation of shear-induced phase transitions in a polymeric system has been performed. The method is based on dynamic density-functional theory. The pathways between a bicontinuous phase with developing gyroid mesostructure and a lamellar/cylinder phase coexistence are investigated for a mixture of flexible triblock ABA-copolymer

G. Kaniadakis, G. Lapenta

The time dependent Tsallis statistical distribution describing anomalous diffusion is usually obtained in the literature as the solution of a non-linear Fokker-Planck (FP) equation [A.R. Plastino and A. Plastino, Physica A, 222, 347 (1995)]. The scope of the present paper is twofold. Firstly we show that this distribution can be obtained also as solution of

D. Caroppo, M. Mannarelli, G. Nardulli, S. Stramaglia

Diluted neural networks with continuous neurons and nonmonotonic transfer function are studied, with both fixed and dynamic synapses. A noisy stimulus with periodic variance results in a mechanism for controlling chaos in neural systems with fixed synapses: a proper amount of external perturbation forces the system to behave periodically with the same period

H. Saleur

These are notes of lectures given at The NATO Advanced Study Institute/EC Summer School on ``New Theoretical Approaches to Strongly Correlated Systems'' (Newton Institute, April 2000). They are a sequel to the notes I wrote two years ago for the Summer School ``Topological Aspects of Low Dimensional Systems'', (Les Houches, July 1998). In thi

A. T. Filip, B. H. Hoving, F. J. Jedema, B. J. van Wees

The electrical injection of spin polarized electrons in a semiconductor can be achieved in principle by driving a current from a ferromagnetic metal, where current is known to be significantly spin polarized, into the semiconductor via ohmic conduction. For detection a second ferromagnet can be used as drain. We studied submicron lateral spin valve junctions

Konstantin Kikoin, Yshai Avishai

When a cerocene molecule is chemisorbed on metallic substrate, or when an asymmetric double dot is hybridized with itinerant electrons, its singlet ground state crosses its lowly excited triplet state, leading to a competition between the Zhang-Rice mechanism of singlet-triplet splitting in a confined cluster and the Kondo effect (which accompanies the tunne

Masatoshi Imada, Tsuyoshi Kashima

A numerical algorithm for studying strongly correlated electron systems is proposed. The groundstate wavefunction is projected out after numerical renormalization procedure in the path integral formalism. The wavefunction is expressed from the optimized linear combination of retained states in the truncated Hilbert space with numerically chosen basis. This a

G. K. Nicholls

The Arak process is a solvable stochastic process which generates coloured patterns in the plane. Patterns are made up of a variable number of random non-intersecting polygons. We show that the distribution of Arak process states is the Gibbs distribution of its states in thermodynamic equilibrium in the grand canonical ensemble. The sequence of Gibbs distri

Heather J. Fleming, Douglas P. Hamilton

We present analytic and numerical results which illustrate the effects of Jupiter's accretion of nebular gas and the planet's radial migration on its Trojan companions. Initially, we approximate the system by the planar circular restricted three-body problem and assume small Trojan libration amplitudes. Employing an adiabatic invariant calculation, w

James S. Bullock, Andrey V. Kravtsov, David H. Weinberg

We develop an explicit model for the formation of the stellar halo from tidally disrupted, accreted dwarf satellites in the cold dark matter (CDM) framework, focusing on predictions testable with the Sloan Digital Sky Survey (SDSS) and other wide-field surveys. Subhalo accretion and orbital evolution are calculated using a semi-analytic approach within the P

Frank C. Jones, Andrew Lukasiak, Vladimir Ptuskin, William Webber

In an attempt to understand the source and propagation of galactic cosmic rays we have employed the Modified Weighted Slab technique along with recent values of the relevant cross sections to compute primary to secondary ratios including B/C and Sub-Fe/Fe for different galactic propagation models. The models that we have considered are the disk-halo diffusio

Riccardo Scarpa, C. Megan Urry

Empirical evidence suggests that elliptical galaxies hosting a radio source may not be different from normal non-radio ellipticals. To test this possibility, we use Monte Carlo simulations to reproduce the distribution of radio galaxies in the radio-optical luminosity plane. The input parameters of the simulation are the optical luminosity function (LF) of e

F. Finelli

We investigate the possibility that electromagnetic fluctuations are amplified in expanding universe by parametric resonance, during the oscillatory regime of a scalar field to which they are coupled. We consider scalar electrodynamics and we find that electromagnetic fluctuations undergo exponential instabilities. This mechanism could have some relevance fo

C. Adami, M. P. Ulmer, A. K. Romer, R. C. Nichol

We present the results of a set of simulations designed to quantify the selection function of the Bright SHARC survey for distant clusters. The statistical significance of the simulations relied on the creation of thousands of artificial clusters with redshifts and luminosities in the range 0.25<z<0.95 and 0.5<L_X<10x10^44 erg/s (0.5-2.0 keV). We created 1 s

C. R. Keeton, D. Christlein, A. I. Zabludoff

We predict how the observed variations in galaxy populations with environment affect the number and properties of gravitational lenses in different environments. Two trends dominate: lensing strongly favors early-type galaxies, which tend to lie in dense environments, but dense environments tend to have a larger ratio of dwarf to giant galaxies than the fiel

M. Coleman Miller

Kilohertz QPO sources are reasonably well-characterized observationally, but many questions remain about the theoretical framework for these sources and the consequent implications of the observations for disk physics, strong gravity, and dense matter. We contrast the predictions and implications of the most extensively studied class of kilohertz QPO models,

L. V. E. Koopmans, A. G. de Bruyn, C. D. Fassnacht, D. R. Marlow

We present radio, optical, near-infrared and spectroscopic observations of the source B0827+525. We consider this source as the best candidate from the Cosmic Lens All-Sky Survey (CLASS) for a `dark lens&#39; system or binary radio-loud quasar. The system consists of two radio components with somewhat different spectral indices, separated by 2.815 arcsec. VL

P. N. Best

An analysis of the environments around a sample of 28 3CR radio galaxies with redshifts 0.6 < z < 1.8 is presented, based primarily upon K--band images down to K ~ 20 taken using the UK Infrared Telescope (UKIRT). A net overdensity of K-band galaxies is found in the fields of the radio galaxies, with the mean excess counts being comparable to that expected f

M. Volonteri, P. Saracco, G. Chincarini, M. Bolzonella

We present an analysis of the optical data of the Hubble Deep Field South. We derive F300W(AB), F450W(AB), F606W(AB) and F814W(AB) number counts for galaxies in all four bands. The slope is steeper at shortest wavelengths: we estimated gamma(F300W(AB))=0.47, gamma(F450W(AB))=0.35, gamma(F606W(AB))=0.28 and gamma(F814W(AB))=0.28. Morphological number counts a

K. Kifonidis, T. Plewa, H. -Th. Janka, E. Mueller

New two-dimensional, high-resolution calculations of a core collapse supernova in a 15 Msol blue supergiant are presented, which cover the entire evolution from shock revival until the first few hours of the explosion. Explosive nucleosynthesis, its dependence upon convective mixing during the first second of the evolution and the growth of Rayleigh-Taylor i

Shaun Cole, Cedric Lacey, Carlton Baugh, Carlos Frenk

We describe the GALFORM semi-analytic model for calculating the formation and evolution of galaxies in hierarchical models. It improves upon, and extends, the Cole et al 1994 model. The model employs a new Monte-Carlo algorithm to follow the merging evolution of dark matter halos with arbitrary mass resolution. It incorporates realistic descriptions of the d

J. J. M. in &#39;t Zand, L. Kuiper, L. Amati, L. A. Antonelli

GRB 991014 is one of the shortest gamma-ray bursts detected so far with the Wide Field Cameras aboard BeppoSAX, both in gamma-rays and X-rays. The duration is 9.6 sec in 2-28 keV and 3.2 sec in 40 to 700 keV (as measured between the times when 5 and 95% of the burst photons have been accumulated). We refine the InterPlanetary Network annulus of the burst, pr

Peter Berczik

A new Chemo - Dynamical Smoothed Particle Hydrodynamic (CD - SPH) code is presented. The disk galaxy is described as a multi - fragmented gas and star system, embedded in a cold dark matter halo. The star formation (SF) process, SNII, SNIa and PN events as well as chemical enrichment of gas have been considered within the framework of the standard SPH model.

Peter Berczik, Sergei Kravchuk

The evolving galaxy is considered as a system of baryonic fragments embedded into the static dark nonbaryonic (DH) and baryonic (BH) halo and subjected to gravitational and viscous interactions. Although the chemical evolution of each separate fragment is treated in the frame of one -- zone close box model with instantaneous recycling, its star formation (SF

Sandip K. Chakrabarti, Banibrata Mukhopadhyay

Chandrasekhar separated the Dirac equation for spinning and massive particles in Kerr geometry into radial and angular parts. Here we solve the complete wave equation and find out how the Dirac wave scatters off Kerr black holes. The eigenfunctions, eigenvalues and reflection and transmission co-efficients are computed. We compare the solutions with several

Lucimara P. Martins, Sueli M. M. Viegas

Estimates of the gas temperature in planetary nebulae obtained from the [O III] emission line ratio and from the Balmer discontinuity indicate differences reaching up to 6000 K (Liu and Danziger 1993). The [O III] temperature is commonly used to obtain the ionic fractions of highly ionized ions, particularly the O++ and Ne++ ions when using the empirical met

Antonio Pineda, Joan Soto

We resum the leading ultrasoft logs of the singlet and octet static QCD potentials within potential NRQCD. We then obtain the complete three-loop renormalization group improvement of the singlet QCD static potential. The discrepancies between the perturbative evaluation and the lattice results at short distances are slightly reduced.

Troels Harmark

We conjecture the existence of two new non-gravitational six-dimensional string theories, defined as the decoupling limit of NS5-branes in the background of near-critical electrical two- and three-form RR fields. These theories are space-time non-commutative Little String Theories with open branes. The theory with (2,0) supersymmetry has an open membrane in

G. Palma, T. Meyer, R. Labbé

In recent works (BHP), a generalized universality has been proposed, linking phenomena as dissimilar as 2D magnetism and turbulence. To test these ideas, we performed a MC study of the 2D XY-model. We found that the shape of the probability distribution function for the magnetization M is non Gaussian and independent of the system size --in the range of the

Gabriel Istrate

We determine the asymptotical satisfiability probability of a random at-most-k-Horn formula, via a probabilistic analysis of a simple version, called PUR, of positive unit resolution. We show that for $k=k(n)\rightarrow \infty$ the problem can be ``reduced&#39;&#39; to the case k(n)=n, that was solved in cs.DS/9912001. On the other hand, in the case k= a con

L. Borissov, J. Conrad, M. Shaevitz

Most ongoing supersymmetry searches have concentrated on the high-energy frontier. High-intensity fixed target beamlines, however, offer an opportunity to search for supersymmetric particles with long lifetimes and low cross-sections in regions complementary to the ones accessible to collider experiments. In this paper, we consider R-parity violating supersy

O. Vafek, A. Melikyan, M. Franz, Z. Tesanovic

Quasiparticles in the vortex lattice of strongly type-II superconductors are investigated by means of a singular gauge transformation applied to the tight binding lattice Bogoliubov-de Gennes Hamiltonian. We present a detailed derivation of the gauge invariant effective low energy Hamiltonian for the quasiparticle-vortex system and show how the physics of th

D. S. Callaway, M. E. J. Newman, S. H. Strogatz, D. J. Watts

Recent work on the internet, social networks, and the power grid has addressed the resilience of these networks to either random or targeted deletion of network nodes. Such deletions include, for example, the failure of internet routers or power transmission lines. Percolation models on random graphs provide a simple representation of this process, but have

Joel Giedt

In string-inspired semi-realistic heterotic orbifolds models with an anomalous $U(1)_X$, a nonzero Kobayashi-Masakawa (KM) phase is shown to arise generically from the expectation values of complex scalar fields, which appear in nonrenormalizable quark mass couplings. Modular covariant nonrenormalizable superpotential couplings are constructed. A toy $Z_3$ o

Jonathan L. Rosner

The Fermilab Tevatron&#39;s operation for fixed-target physics from its start in 1983 until the end of fixed-target running in 2000 was marked by extraordinary peoductivity and variety. Some of the changing theoretal issues associated with this program are reviewed.

Vasili Perebeinos, Philip B. Allen

Resonant behavior of the Raman process is predicted when the laser frequency is close to the orbital excitation energy of LaMnO3 at 2 eV. The incident photon creates a vibrationally excited self-trapped ``orbiton'' state from the orbitally-ordered Jahn-Teller (JT) ground state. Trapping occurs by local oxygen rearrangement. Then the Franck-Condon mechanism a

A. M. Stasto, K. Golec-Biernat, J. Kwiecinski

We observe that the saturation model of deep inelastic scattering, which successfully describes inclusive and diffractive data at small x, predicts a geometric scaling of the total gamma^* p cross section in the region of small Bjorken variable x. The geometric scaling in this case means that the cross section is a function of only one dimensionless variable

L. Apanasevich, M. Begel, C. Bromberg, T. Ferbel

We present a study of inclusive direct-photon and pion production in hadronic interactions, focusing on a comparison of the ratio of gamma/pi0 yields with expectations from next-to-leading order perturbative QCD (NLO pQCD). We also examine the impact of a phenomenological model involving k_T smearing (which approximates effects of additional soft-gluon emiss

K. G. Sandeman, A. J. Schofield

A simple model of anisotropic scattering in a quasi two-dimensional metal is studied. Its simplicity allows an analytic calculation of transport properties using the Boltzmann equation and relaxation time approximation. We argue that the c-axis magnetoresistance provides the key test of this model of transport. We compare this model with experiments on overd

Dong Lai, David F. Chernoff, James M. Cordes

We study implications for the apparent alignment of the spin axes, proper-motions, and polarization vectors of the Crab and Vela pulsars. The spin axes are deduced from recent Chandra X-ray Observatory images that reveal jets and nebular structure having definite symmetry axes. The alignments indicate these pulsars were born either in isolation or with negli

Douglas A. Glenzinski, Ulrich Heintz

The Standard Model of electroweak interactions has had great success in describing the observed data over the last three decades. The precision of experimental measurements affords tests of the Standard Model at the quantum loop level beyond leading order. Despite this great success it is important to continue confronting experimental measurements with the S

R. Aurich, F. Steiner

The fluctuations of the cosmic microwave background (CMB) are investigated for a hyperbolic universe with finite volume. Four-component models with radiation, matter, vacuum energy, and an extra spatially constant dark energy X-component are considered. The general solution of the Friedmann equation for the cosmic scale factor a(eta) is given for the four-co

Koji Uryu, Masaru Shibata, Yoshiharu Eriguchi

We investigate close binary neutron stars in quasiequilibrium states in a general relativistic framework. We assume conformal flatness for the spatial metric and irrotational velocity field for the neutron stars. We adopt the polytropic equation of state. The computation is performed for the polytropic index n(=0.5, 0.66667, 0.8, 1, 1.25), and compactness of

R. Wielen, H. Lenhardt, H. Schwan, C. Dettbarn

The combination of ground-based astrometric compilation catalogues, such as the FK5 or the GC, with the results of the ESA Astrometric Satellite HIPPARCOS produces for many thousands of stars proper motions which are significantly more accurate than the proper motions derived from the HIPPARCOS observations alone. In Paper I (Wielen et al. 1999, A&A 347, 104

A. B. Kaganovich

A field theory is developed based on the idea that the effective action of yet unknown fundamental theory, at energy scale below M_{p} has the form of expansion in two measures: S=\intd^{4}x[ΦL_{1}+\sqrt{-g}L_{2}] where the new measure Φis defined using the third-rank antisymmetric tensor. In the new variables (Einstein frame) all equations of motion take ca

Werner Kerler

Comparing recent lattice results on chiral fermions and old continuum results for the index puzzling questions arise. To clarify this issue we start with a critical reconsideration of the results on finite lattices. We then work out various aspects of the continuum limit. After determining bounds and norm convergences we obtain the limit of the anomaly term.

P. F. L. Maxted, T. R. Marsh, R. C. North

We present spectra of the pulsating sdB star KPD1930+2752 which confirm that this star is a binary. The radial velocities measured from the H-alpha and HeI6678 spectral lines vary sinusoidally with the same period (2h 17m) as the ellipsoidal variability seen by Billeres et al. (2000). The amplitude of the orbital motion (349.3+-2.7 km/s) combined with the ca

M. R. Evans

The phenomenon of phase transitions in one-dimensional systems is discussed. Equilibrium systems are reviewed and some properties of an energy function which may allow phase transitions and phase ordering in one dimension are identified. We then give an overview of the one-dimensional phase transitions which we have been studied in nonequilibrium systems. A

Chiho Nonaka, Eiji Honda, Shin Muroya

A full (3+1)-dimensional calculation using the Lagrangian hydrodynamics is proposed for relativistic nuclear collisions. The calculation enables us to evaluate anisotropic flow of hadronic matter which appears in non-central and/or asymmetrical relativistic nuclear collisions. Applying hydrodynamical calculations to the deformed uranium collisions at AGS ene

R. Balian, P. Valentin

The state of a thermodynamic system being characterized by its set of extensive variables $q^{i}(i=1,...,n) ,$ we write the associated intensive variables $γ_{i},$ the partial derivatives of the entropy $ S(q^{1},...,q^{n}) \equiv q_{0},$ in the form $γ_{i}=-p_{i}/p_{0}$ where $p_{0}$ behaves as a gauge factor. When regarded as independent, the variables $q^

Bum-Hoon Lee, Kimyeong Lee, Hyun Seok Yang

We construct the consistent CP(n) model on noncommutative plane. The Bogomolny bound on the energy is saturated by (anti-)self-dual solitons with integer topological charge, which is independent of their scaling and orientation. This integer quantization is satisfied for our general solutions, which turns out regular everywhere. We discuss the possible impli

Dennis D. Dietrich, Gouranga. C. Nayak, Walter Greiner

We derive source terms for the production of quarks and gluons from the QCD vacuum in the presence of a space-time dependent external chromofield A_{cl} to the order of S^{(1)}. We found that the source terms for the parton production processes A_{cl} -> q\bar{q} and A_{cl},A_{cl}A_{cl} -> gg also include the annihilation processes q\bar{q} -> A_{cl} and gg

Keith S. M. Lee, Raymond R. Volkas, Yvonne Y. Y. Wong

We derive an approximate relic neutrino asymmetry evolution equation that systematically incorporates repopulation processes from the full quantum kinetic equations (QKEs). It is shown that in the collision dominant epoch, the said equation reduces precisely to the expression obtained previously from the static/adiabatic approximation. The present treatment

Raymond R. Volkas, Yvonne Y. Y. Wong

We demonstrate that the relic neutrino asymmetry evolution equation derived from the quantum kinetic equations (QKEs) reduces to the Boltzmann limit that is dependent only on the instantaneous neutrino number densities, in the adiabatic limit in conjunction with sufficient damping. An original physical and/or geometrical interpretation of the adiabatic appro

Volker Bromm, Rolf P. Kudritzki, Abraham Loeb

We calculate the generic spectral signature of an early population of massive stars at high redshifts. For metal-free stars in the mass range of 100-1000 solar masses, we find that the combined spectral luminosity per unit stellar mass is almost independent of the mass distribution of these stars. To zeroth order, the generic spectrum resembles a black-body

Massimo Blasone, Petr Jizba, Giuseppe Vitiello

We show that the dissipation term in the Hamiltonian for a couple of classical damped-amplified oscillators manifests itself as a geometric phase and is actually responsible for the appearance of the zero point energy in the quantum spectrum of the 1D linear harmonic oscillator. We also discuss the thermodynamical features of the system. Our work has been in

Hans Halvorson

Many of the &#34;counterintuitive&#34; features of relativistic quantum field theory have their formal root in the Reeh-Schlieder theorem, which in particular entails that local operations applied to the vacuum state can produce any state of the entire field. It is of great interest, then, that I.E. Segal and, more recently, G. Fleming (in a paper entitled &

Jan Skibinski

Factorization method is developed for a family of discretely spiked harmonic oscillators. Two sets of intertwining and ladder operators are presented to algebraically generate eigenstates with energies isomorphic to those of the ordinary harmonic oscillator. Normalization conditions are examined to reject unphysical cases. Generic theory is specialized to on

John Calsamiglia, Norbert Lütkenhaus

In a photonic realization of qubits the implementation of quantum logic is rather difficult due the extremely weak interaction on the few photon level. On the other hand, in these systems interference is available to process the quantum states. We formalize the use of interference by the definition of a simple class of operations which include linear optical

J. I. Cirac, W. Dür, B. Kraus, M. Lewenstein

We study when a physical operation can produce entanglement between two systems initially disentangled. The formalism we develop allows to show that one can perform certain non-local operations with unit probability by performing local measurement on states that are weakly entangled.

C. K. Law, H. T. Ng, P. T. Leung

We report an interaction that controls spin squeezing in a collection of spin 1/2 particles. We describe how spin squeezing can be generated and maintained in time. Our scheme can be applied to control the spin squeezing in a Bose condensate with two internal spin states.

Enrico Onofri

Landau levels have represented a very rich field of research, which has gained widespread attention after their application to quantum Hall effect. In a particular gauge, the holomorphic gauge, they give a physical implementation of Bargmann&#39;s Hilbert space of entire functions. They have also been recognized as a natural bridge between Feynman&#39;s path

B. J. King

New self-consistent parameter sets are presented and discussed for muon collider rings at center-of-mass energies of 10, 30 and 100 TeV. All three parameter sets attain luminosities of 3 x 10^35 /cm^2/s. The parameter sets benefit from new insights gained at the HEMC&#39;99 workshop that considered the feasibility of many-TeV muon colliders.

Ronald L. Walsworth, David Bear, Marc Humphrey, Edward M. Mattison

We present two new measurements constraining Lorentz and CPT violation using the Xe-129 / He-3 Zeeman maser and atomic hydrogen masers. Experimental investigations of Lorentz and CPT symmetry provide important tests of the framework of the standard model of particle physics and theories of gravity. The two-species Xe-129 / He-3 Zeeman maser bounds violations

Ronald L. Walsworth, David F. Phillips

We present two new measurements constraining Lorentz and CPT violation using the Xe-129 / He-3 Zeeman maser and atomic hydrogen masers. Experimental investigations of Lorentz and CPT symmetry provide important tests of the framework of the standard model of particle physics and theories of gravity. The two-species Xe-129 / He-3 Zeeman maser bounds violations

Rainer Wanzenberg

The lattice for the present design of the TESLA Linear Collider with integrated X-Ray Laser Facility is basically a FODO structure with constant beta-function. There are more than 800 individually powered superconducting quadrupoles to focus the beam in the two main linear accelerators (each with a length of 15 km). For the availability of the beams it is im

P J Clark

To make precision measurements with a CsI(Tl) calorimeter in a high luminosity environment requires that the crystals are well calibrated and continually monitored for radiation damage. This should not effect the total integrated luminosity which is particularly important for the \babar calorimeter to enable it to make CP violation measurements in the $B$ me

Y. Thiery, J. Gao, J. Le Duff

A bunching system is proposed for the initial stage of CTF3 which consists of one (two) 3 GHz prebunchers and one 3 GHz travelling wave (TW) buncher with variable phase velocities. The electron beam is emitted from a 140 KV DC gun. Since the macropulse beam current (3.5 A) at the exit of the TW buncher is rather high, inside the TW buncher one has to take th

S. Drozdz, M. Wojcik

We investigate the origin of order in the low-lying spectra of many-body systems with random two-body interactions. Contrary to the common belief our study based both on analytical as well as on numerical arguments shows that these are the higher $J$-sectors whose ground states are more orderly than the ones in the J=0-sector. A predominance of J=0 ground st

B. Barmore, A. T. Kruppa, W. Nazarewicz, T. Vertse

The newly developed nonadiabatic method based on the coupled-channel Schroedinger equation with Gamow states is used to study the phenomenon of proton radioactivity. The new method, adopting the weak coupling regime of the particle-plus-rotor model, allows for the inclusion of excitations in the daughter nucleus. This can lead to rather different predictions

K. Paech, M. Reiter, A. Dumitru, H. Stoecker

We investigate the excitation function of directed flow, which can provide a clear signature of the creation of the QGP and demonstrate that the minimum of the directed flow does not correspond to the softest point of the EoS for isentropic expansion. A novel technique measuring the compactness is introduced to determine the QGP transition in relativistic-he

Laura Tolos, Angels Ramos, Artur Polls, Thomas T. S. Kuo

The momentum dependence of the antikaon optical potential in nuclear matter is obtained from a microscopic and self-consistent calculation using the meson-exchange Jülich $\bar{K}N$ interaction. Two self-consistent schemes are discussed, which would lead to substantially different predictions for the width of ${\bar K}$ nuclear bound states. The effect of hi

B. K. Agrawal, Tapas Sil, J. N. De, S. K. Samaddar

The relativistic Hartree-BCS theory is applied to study the temperature dependence of nuclear shape and pairing gap for $^{166}Er$ and $^{170}Er$. For both the nuclei, we find that as temperature increases the pairing gap vanishes leading to phase transition from superfluid to normal phase as is observed in nonrelativistic calculation. The deformation evolve

N. M. J. Woodhouse

Hitchin&#39;s twistor treatment of Schlesinger&#39;s equations is extended to the general isomonodromic deformation problem. It is shown that a generic linear system of ordinary differential equations with gauge group SL(n,C) on a Riemann surface X can be obtained by embedding X in a twistor space Z on which sl(n,C) acts. When a certain obstruction vanishes,

D. A. Wisniacki, F. Borondo, E. Vergini, R. M. Benito

The scarring effect of short unstable periodic orbits up to times of the order of the first recurrence is well understood. Much less is known, however, about what happens past this short-time limit. By considering the evolution of a dynamically averaged wave packet, we show that the dynamics for longer times is controlled by only a few related short periodic

Michael Dennin

I report on the effects of a periodic modulation of the control parameter on electroconvection in the nematic liquid crystal I52. Without modulation, the primary bifurcation from the uniform state is a direct transition to a state of spatiotemporal chaos. This state is the result of the interaction of four, degenerate traveling modes: right and left zig and

David M. Bressoud

This paper highlights three known identities, each of which involves sums over alternating sign matrices. While proofs of all three are known, the only known derivations are as corollaries of difficult results. The simplicity and natural combinatorial interpretation of these identities, however, suggest that there should be direct, bijective proofs.

G. W. Wei

A new computational algorithm, the discrete singular convolution (DSC), is introduced for computational electromagnetics. The basic philosophy behind the DSC algorithm for the approximation of functions and their derivatives is studied. Approximations to the delta distribution are constructed as either bandlimited reproducing kernels or approximate reproduci

Hendrik Grundling

A host algebra generalises the concept of a group algebra as follows. Let F be a unital C*-algebra, and let S_0 be a proper subset of its states within which one wants to keep the analysis (e.g. F is the group algebra of a discrete group G, and S_0 is the set of states continuous w.r.t. some nondiscrete topology of G). Then a host algebra is a C*-algebra L f

Michael J. Falk, Nicholas J. Proudfoot

Let \A be a complex hyperplane arrangement, and let $X$ be a modular element of arbitrary rank in the intersection lattice of \A. We show that projection along $X$ restricts to a fiber bundle projection of the complement of \A to the complement of the localization $\A_X$ of \A at $X$. The fiber is the decone of a realization of the complete principal truncat

T. Banks

It is conjectured that M-theory in asymptotically flat spacetime must be supersymmetric, and that the observed SUSY breaking in the low energy world must be attributed to the existence of a nonzero cosmological constant. This would be consistent with experiment, if the {\it critical exponent} $α$ in the relation $M_{SUSY} \sim M_P (Λ/M_P^4)^α$ took on the va

J. Fuchs, P. Kaste, W. Lerche, C. Lutken

We investigate certain fixed points in the boundary conformal field theory representation of type IIA D-branes on Gepner points of K3. They correspond geometrically to degenerate brane configurations, and physically lead to enhanced gauge symmetries on the world-volume. Non-abelian gauge groups arise if the stabilizer group of the fixed points is realized pr

A. Belhaj, E. H. Saidi

Using a geometric realization of the $SU(2)_R$ symmetry and a procedure of factorisation of the gauge and $SU(2)_R$ charges, we study the small instanton singularities of the Higgs branch of supersymmetric $U(1)^r$ gauge theories with eight supercharges. We derive new solutions for the moduli space of vacua preserving manifestly the eight supercharges. In pa

I. Benkaddour, A. El. Rhalami, E. H. Saidi

Using recent results on string on $AdS_{3}\times N^d$, where N is a d-dimensional compact manifold, we re-examine the derivation of the non trivial extension of the (1+2) dimensional-Poincaré algebra obtained by Rausch de Traubenberg and Slupinsky, refs [1] and [29]. We show by explicit computation that this new extension is a special kind of fractional supe

Hiroshi Ishikawa, Satoshi Watamura

We construct the boundary state for the D-brane in the SU(2) group manifold directly in terms of the group variables. We propose a matching condition for the left- and the right-moving sectors including the zero modes that describes a D-brane of the Neumann-type. The free field realization of the WZW model is used to obtain the boundary state subject to the

John H. Schwarz

Superstring theory has continued to develop at a rapid clip in the past few years. Following a quick review of some of the major discoveries prior to 1998, this talk focuses on a few of the more recent developments. The topics I have chosen to present are 1) the use of K-theory to classify conserved charges carried by D-branes; 2) tachyon condensation on uns

Herman Verlinde

We propose that the UV/IR relation that underlies the AdS/CFT duality may provide a natural mechanism by which high energy supersymmetry can have large distance consequences. We motivate this idea via (a string realization of) the Randall-Sundrum scenario, in which the observable matter is localized on a matter brane separate from the Planck brane. As sugges

H. J. Drescher, M. Hladik, S. Ostapchenko, T. Pierog

We present a new parton model approach for hadron-hadron interactions and, in particular, for the initial stage of nuclear collisions at very high energies (RHIC, LHC and beyond). The most important aspect of our approach is a self-consistent treatment, using the same formalism for calculating cross sections and particle production, based on an effective, QC

Vincenzo Cirigliano, John F. Donoghue, Eugene Golowich

We expose a potential flaw in standard treatments of weak decay amplitudes, including that of epsilon&#39;/epsilon. We show that (contrary to conventional wisdom) dimension-eight operators do contribute to weak amplitudes, at order G_F alpha_s and without 1/M_W^2 suppression. We demonstrate the existence of these operators with a simple weak hamiltonian and

A. Guffanti, G. E. Smye

We use the &#34;dispersive method&#34; to investigate non-perturbative effects in the transverse momentum distribution of vector bosons produced in p-pbar collisions. The assumption of a non-perturbative modification to the running coupling at low scales leads to additional contributions in impact parameter space proportional to -b^2 log Q^2 and -b^2. Our re

A. P. Chapovsky, V. A. Khoze, W. J. Stirling

The bremsstrahlung spectrum of photons accompanying $W$ pair production depends on the decay width of the unstable $W$ bosons. The dependence arises from the interference between emission at different stages of the production and decay process. We present a quantitative discussion of this effect, and consider the implications for measurements at LEP2 and LC

B. I. Ermolaev

A short review of recent theoretical results on the Deep Inelastic Scattering is presented.

M. D. Scadron

First, the LσM is nonperturbatively solved via loop-order gap equations. Then the Nambu-Goldstone theorem (NGT) is expressed in LσM language. Next, the Lee null tadpole sum for this SU(2) LσM theory is shown to require N_c = 3. Then LσM s-wave chiral cancellations are studied in tree-and in loop-order. Also, vector meson dominance (VMD) is shown to follow fr

Dmitri E. Kharzeev, Yuri V. Kovchegov, Eugene Levin

We study the role of semi-classical QCD vacuum solutions in high energy scattering by considering the instanton contribution to hadronic cross sections. We propose a new type of instanton-induced interactions (``instanton ladder&#39;&#39;) that leads to the rising with energy hadronic cross section of Regge type (the Pomeron). We argue that this interaction

Sinya Aoki, Yoshinobu Kuramashi

Renormalization factors for $ΔS =1$ four-quark operators in the effective weak Hamiltonian are perturbatively evaluated in domain-wall QCD. The one-loop corrections of $ΔS=1$ four-quark operators consist of two types of diagrams: one is gluon exchange between quark lines and the other is penguin diagrams containing quark loops. Combining both contributions,

T. Affolder

A full angular analysis has been performed for the pseudo-scalar to vector-vector decays, B0 --> J/psi K* and B_s --> J/psi phi, to determine the amplitudes for decays with parity-even longitudinal and transverse polarization and parity-odd transverse polarization. The measurements are based on 190 B0 candidates and 40 B_s candidates collected from a data se

M. K. Suleymanov, O. B. Abdinov, N. S. Angelov, A. S. Vodopyanov

The experimental results on the relation between the number of events, the angular distributions of protons and full number of protons are presented for ${}^{12}CC$-interactions at the momentum of 4.2 A GeV/c. The influence of nuclear fragmentation process on the results is also considered. The obtai- ned results confirm the assumption that there exist the c