August 1996 arXiv papers — page 3

H. Diamant, D. Andelman

We present a theory for the kinetics of surfactant adsorption at the interface between an aqueous solution and another fluid (air, oil) phase. The model relies on a free-energy formulation. It describes both the diffusive transport of surfactant molecules from the bulk solution to the interface, and the kinetics taking place at the interface itself. When app

Steven R. White, D. J. Scalapino

Using density matrix renormalization group techniques, we have studied the ground state of the 4-leg t-J ladder doped near half-filling. Depending upon J/t and the hole doping x, three types of ground state phases are found: (1) a phase containing d_{x^2-y^2} pairs; (2) a striped CDW domain-wall phase, and (3) a phase separated regime. A CDW domain-wall cons

T. Grabo, E. K. U. Gross

Using the optimized effective potential method in conjunction with the semi-analytical approximation due to Krieger, Li and Iafrate, we have performed fully self-consistent exact exchange-only density-functional calculations for diatomic molecules with a fully numerical basis-set-free molecular code. The results are very similar to the ones obtained with the

Debabrata Biswas

We study ray dynamics in a square billiard that allows mode conversion and is parametrised by $κ$, the ratio of the velocities of the two modes. At $κ\rightarrow 1^+$, conversion occurs at every reflection and periodic orbits proliferate exponentially. As $κ$ increases beyond $\sqrt{2}$, the collection of daughter rays explore only three momentum directions

Debabrata Biswas

We demonstrate for a generic pseudointegrable billiard that the number of periodic orbit families with length less than $l$ increases as $πb_0l^2/\langle a(l) \rangle$, where $b_0$ is a constant and $\langle a(l) \rangle$ is the average area occupied by these families. We also find that $\langle a(l) \rangle$ increases with $l$ before saturating. Finally, we

JJ Kavelaars, D. A. Hanes

We show that the globular cluster luminosity function (GCLF) of the inner halo of the Milky Way is statistically different from the GCLF of the outer halo. We also find a similar difference between the inner and outer halo population of M31. We assert that this difference is evidence for some form of dynamical evolution of the cluster population and/or a dep

David V. Bowen, Samantha J. Osmer, J. Chris Blades, David Tytler

To expand the known number of low-redshift galaxies which lie close to bright ($V < 17.2$) QSO lines of sight, we have identified 24 galaxies within 11 arcmins of nine QSOs which have been observed with the Hubble Space Telescope (HST). Galaxies are found between redshifts of $0.0114-0.145$ and lie between $39-749$ $h^{-1}$ kpc from QSO sightlines. Knowing t

U. Becciani, V. Antonuccio-Delogu, A. Pagliaro

We describe a new parallel N-body code for cosmological simulations. The code is based on a work- and data sharing scheme, and is implemented within the Cray Research Corporation&#39;s CRAFT programming environment. Different data distribution schemes have been adopted for bodies&#39; and tree&#39;s structures. Tests performed for two different types of init

P. Andreani, G. Dall&#39;Oglio, L. Pizzo, L. Martinis

An observing campaign was devoted to the search for the Sunyaev-Zeldovich (S-Z) effect towards X-ray ROSAT Clusters in the millimetric spectral domain. A double channel (1.2 and 2 {\it mm}) photometer was installed at the focus of the 15m Swedish ESO Submillimeter Telescope (SEST) in Chile in september 1994 and 1995 and observations of the targets S1077, A27

Shigeru Yoshida, Hongyue Dai, Charles C. H. Jui, Paul Sommers

We discuss in some detail the production of extremely high energy (EHE) neutrinos with energies above 10^18 eV. The most certain process for producing such neutrinos results from photopion production by EHE cosmic rays in the cosmic background photon field. However, using assumptions for the EHE cosmic ray source evolution which are consistent with results f

F. Halzen

We present the theoretical arguments and describe the accumulating experimental evidence that jets, powered by supermassive black holes, are true cosmic accelerators. They produce photons of TeV energy, possible higher, and may be the enigmatic source of the highest energy cosmic rays. The features of the multi-wavelength emission spectrum are dictated by th

J. Greiner, K. Dennerl, P. Predehl

We have observed GRS 1739-278 with the ROSAT HRI on March 31, 1996. The improved X-ray position proves the identification with an earlier discovered variable radio source. We derive an extinction of A_V = 14+/-2 from the dust scattering halo, which implies a distance of d approx. 6-8.5 kpc. Thus, GRS 1739-278 radiates at least near the Eddington limit for a

Hiraku Mutoh, Toshinari Hirai, Kei-ichi Maeda

We study the stability of a contracting {\it silent universe}, which is a spacetime with irrotational dust and vanishing magnetic part of the Weyl tensor, $H_{ab}=0$. Two general relativistic backgrounds are analyzed; one is an attractor of {\it silent universes}, i.e., a locally Kasner spacetime, and the other is a particular class of inhomogeneous Szekeres

William D. Vacca, Bruno Leibundgut

Using the published photometry and an empirical model of the temporal evolution of the apparent magnitudes in the UBVRI passbands, we have constructed a continuous optical bolometric, or ``quasi-bolometric&#39;&#39;, light curve of the well-observed Type Ia supernova SN 1994D. The optical bolometric light curve is found to have a maximum luminosity of about

Vicki L. Sarajedini, Richard F. Green, Richard E. Griffiths, Kavan U. Ratnatunga

The Hubble Space Telescope WFPC2 is being used to obtain high-resolution images in the V and I bands for several thousand distant galaxies as part of the Medium Deep Survey (MDS). An important scientific aim of the MDS is to identify possible AGN candidates from these images in order to measure the faint end of the AGN luminosity function as well as to study

A. Burrows, W. B. Hubbard, J. I. Lunine, T. Guillot

The recent discoveries of giant planets around nearby stars have galvanized the planetary science community, astronomers, and the public at large. Since {\it direct} detection is now feasible, and is suggested by the recent acquisition of Gl229 B, it is crucial for the future of extrasolar planet searches that the fluxes, evolution, and physical structure of

C. A. da Rocha, G. Krein, L. Wilets

We solve the Schwinger-Dyson equation for the nucleon propagator in the vacuum using $π$, $σ$, and $ω$ mesons. For bare interaction vertices (Hartree-Fock approximation) we obtain a pair of complex-conjugated poles (ghost poles) and for vertices dressed by phenomenological form-factors these ghosts disappeared. We use these two different approaches to evalua

R. Aldrovandi, L. A. Saeger

The Weyl-Wigner prescription for quantization on Euclidean phase spaces makes essential use of Fourier duality. The extension of this property to more general phase spaces requires the use of Kac algebras, which provide the necessary background for the implementation of Fourier duality on general locally compact groups. Kac algebras -- and the duality they i

R. Aldrovandi, L. A. Saeger

The Weyl-Wigner correspondence prescription, which makes large use of Fourier duality, is reexamined from the point of view of Kac algebras, the most general background for noncommutative Fourier analysis allowing for that property. It is shown how the standard Kac structure has to be extended in order to accommodate the physical requirements. An Abelian and

Mehryar Mohri, Michael Riley, Richard Sproat

Speech processing requires very efficient methods and algorithms. Finite-state transducers have been shown recently both to constitute a very useful abstract model and to lead to highly efficient time and space algorithms in this field. We present these methods and algorithms and illustrate them in the case of speech recognition. In addition to classical tec

Jonathan Bagger, Alexander Galperin

The partial spontaneous breaking of rigid N=2 supersymmetry implies the existence of a massless N=1 Goldstone multiplet. In this paper we show that the spin-(1/2,1) Maxwell multiplet can play this role. We construct its full nonlinear transformation law and find the invariant Goldstone action. The spin-1 piece of the action turns out to be of Born-Infeld typ

Martin White, Joe Silk

We discuss observational constraints on models of open inflation. Current data from large-scale structure and the cosmic microwave background prefer models with blue spectra and/or Omega_0 >= 0.3--0.5. Models with minimal anisotropy at large angles are strongly preferred.

L. P. Pitaevskii, A. Rosch

Atoms confined in a harmonic potential show universal oscillations in 2D. We point out the connection of these &#39;&#39;breathing&#39;&#39; modes to the presence of a hidden symmetry. The underlying symmetry SO(2,1), i.e. the two dimensional Lorentz group, allows pulsating solutions to be constructed for the interacting quantum system and for the correspond

H. Rieger, U. Blasum

We study the glassy super-rough phase of a class of solid-on-solid models with a disordered substrate in the limit of vanishing temperature by means of exact ground states, which we determine with a newly developed minimum cost flow algorithm. Results for the height-height correlation function are compared with analytical and numerical predictions. The domai

Bo Soderberg

There exists a generic relationship between the thermodynamics of a continuous polymer with a generic self-interaction and the two-point function of an interacting field-theory. In addition, the (2N)-point function of the resulting field theory is similarly related to a system of N interacting polymers. In the present paper, this relation is explored for the

G. A. Gehring, R. J. Bursill, T. Xiang

We review White&#39;s density matrix renormalisation group method, an increasingly popular method for the solution of low dimensional quantum Hamiltonians. We describe some applications to frustrated spin systems, quantum critical phenomena, two dimensional classical and one dimensional quantum systems at non-zero temperature, and low energy properties of tw

Max Tegmark, Jens Villumsen

Weak gravitational lensing from large-scale structure enhances and reduces the fluxes from extragalactic point sources with an rms amplitude of order 15%. In cosmic microwave background (CMB) experiments, sources exceeding some flux threshold are removed, which means that lensing will modulate the brightness map of the remaining unresolved sources. Since thi

Saburo Kakei

We investigate common algebraic structure for the rational and trigonometric Calogero-Sutherland models by using the exchange-operator formalism. We show that the set of the Jack polynomials whose arguments are Dunkl-type operators provides an orthogonal basis for the rational case.

Aiichi Iwazaki

We show that coherent magnetic field is generated spontaneously when a large domain wall is created in the early universe. It is caused by two dimensional massless fermions bounded to the domain wall soliton. We point out that the magnetic field is a candidate of primordial magnetic field.

Tadayuki Teshima, Toyokazu Sakai

We analyse the quark mass hierarchy and CKM matrix using the universal Yukawa coupling model with small violations precisely. We estimate the ranges of the values of 8 violation parameters (delta1u, delta2u, delta3u, delta1d, delta2d, delta3d, phi2, phi3) in our quark mass matrices satisfying quark mass ratios and CKM matrix, where phi2, phi3 are phases. Wit

Jarmo Hietarinta

Takhtajan has recently studied the consistency conditions for Nambu brackets, and suggested that they have to be skew-symmetric, and satisfy Leibnitz rule and the Fundamental Identity (FI, it is a generalization of the Jacobi identity). If the n&#39;th order Nambu brackets in dimension N is written in terms of the Nambu tensor η, the FI implies two condition

Thorsten Koehler

In this paper it is shown that the Lyman-$α$ transition of a single hydrogen-like system driven by a laser exhibits macroscopic dark periods, provided there exists an additional constant electric field. We describe the photon-counting process under the condition that the polarization of the laser coincides with the direction of the constant electric field. T

G. N. Throumoulopoulos, G. Pantis

The equilibrium of a cylindrical plasma with purely poloidal mass flow and cross section of arbitrary shape is investigated within the framework of the ideal MHD theory. For the system under consideration it is shown that only incompressible flows are possible and, conscequently, the general two dimensional flow equilibrium equations reduce to a single secon

S. Pepin, Fl. Stancu, M. Genovese, J. -M. Richard

We discuss the stability of multiquark systems within the recent model of Glozman et al. where the chromomagnetic hyperfine interaction is replaced by pseudoscalar-meson exchange. We find that such an interaction binds a heavy tetraquark system $QQ\bar q\bar q$ ($Q=c, b$ and $q=u, d)$ by $0.2-0.4$ GeV. This is at variance with results of previous models wher

U. Heinz, C. Hu, S. Leupold, S. Matinyan

We investigate thermalization processes occurring at different time scales in the Yang-Mills-Higgs system at high temperatures. We determine the largest Lyapunov exponent associated with the gauge fields and verify its relation to the perturbatively calculated damping rate of a static gauge boson.

D. M. Gitman

The propagator of a spinning particle in external Abelian field and in arbitrary dimensions is presented by means of a path integral. The problem has different solutions in even and odd dimensions. In even dimensions the representation is just a generalization of one in four dimensions (it has been known before). In this case a gauge invariant part of the ef

D. M. Gitman, S. I. Zlatev

We study the spin factor problem both in $3+1$ and $2+1$ dimensions which are essentially different for spin factor construction. Doing all Grassmann integrations in the corresponding path integral representations for Dirac propagator we get representations with spin factor in arbitrary external field. Thus, the propagator appears to be presented by means of

J. Antonio García, J. David Vergara, Luis F. Urrutia

Starting from an associated reparametrization-invariant action, the generalization of the BRST-BFV method for the case of nonstationary systems is constructed. The extension of the Batalin-Tyutin conversional approach is also considered in the nonstationary case. In order to illustrate these ideas, the propagator for the time-dependent two-dimensional rotor

Yutaka Hosotani, Ramon Rodriguez

We evaluate the chiral condensate and Polyakov loop in two-dimensional QED with a fermion of an arbitrary mass ($m$). We find discontinuous $m$ dependence in the chiral condensate and anomalous temperature dependence in Polyakov loops when the vacuum angle $θ$$\sim$$π$ and $m$=O($e$). These nonperturbative phenomena are due to the bifurcation process in the

S. Yu. Khlebnikov, I. I. Tkachev

We study numerically the decay of massive and massless inflatons into massive excitations, via a $ϕ^2 X^2$ coupling, in the expanding Universe. We find that a wide enough resonance can survive the Universe expansion, though account for the expansion is very important for determining precisely how wide it should be. For a massive inflaton, the effective produ

Sean Fleming

Presented at the Meeting of the Division of Particles and Fields, August 1996, in Minneapolis. The work presented here is based upon a recent paper (hep-ph/9608413) done in collaboration with Oscar F. Hernandez, Ivan Maksymyk, and Helene Nadeau. The NRQCD predictions for the polarization of the J/psi produced in b->J/psi+X, as well as the helicity-summed pro

Minos Axenides, Andrei Johansen, Holger B. Nielsen, Ola Tornkvist

An introduction to the subject of baryon number non-conservation in the electroweak theory at high temperatures or energies is followed by a summary of our discovery of an infinite surface of sphaleron-like configurations which play a key role in baryon-number non-conserving transitions in a hot electroweak plasma.

Vittorio Del Duca

In this review talk I consider the physics of rapidity gaps between two jets at hadron colliders, as a preliminary investigation toward understanding the production of a Higgs boson via weak boson fusion at the LHC.

I. Kuss

An improved effective vector-boson approximation is applied to hadron-hadron collisions. I include an approximative treatment and compare with a complete perturbative calculation for the specific example of $ZZ$ production. The results are also compared with existing approaches. The effective vector-boson approximation in this form is accurate enough to repr

Stefano Moretti

In this paper, we extend the analyses carried out in a previous article for $WW$-fusion to the case of Higgs production via $ZZ$-fusion within the Standard Model at the Next Linear Collider, in presence of electromagnetic radiation due real photon emission. Calculations are carried out at tree-level and rates of the leading order (LO) processes $e^+e^-\right

Marco Genovese

A simple mixing scheme describing the $f_0(1500)$ and the $f_0(1700)$ as mixed states of a $\bar s s$ meson and a digluonium is reconsidered at the light of new experimental data.

G. Barenboim, J. Bernabeu, M. Raidal

A left-right model with spontaneous $CP$ breakdown, consistent with the particle physics phenomenology, is presented. Constraints on free parameters of the model: mass of the new right handed gauge boson $M_2$ and ratio $r$ of the two vacuum expectation values of the bidoublet, are found from the measurement of $ε$ in the kaon system. For most of the paramet

Christoph Greub, Tobias Hurth

The calculation of the $O(\a_s)$ virtual corrections to the matrix element of the inclusive decay $b \to s γ$ is reported. These contributions drastically reduce the large renormalization scale dependence of the leading logarithmic calculation. Combining these results with the preliminary result for the Wilson coefficient $C_7(m_b)$ calculated recently by Ch

A. Duncan, E. Eichten, H. Thacker

A method in which electromagnetic properties of hadrons are studied by direct simulation of dynamical photon effects is applied to the extraction of the isomultiplet structure of the octet baryons. Using 187 configurations at $β=5.7$ with Wilson action, and up and down quark masses determined from the meson spectrum, the nucleon splitting is found to be $1.5

JLQCD Collaboration, S. Aoki, M. Fukugita, S. Hashimoto

We explore the problems in calculating the decay constant for heavy-light mesons using the quenched Wilson quark action for both heavy and light quarks. We find that the continuum limit of the decay constant is reasonably converged among different prescriptions after the continuum limit is taken. A number of technical problems associated with prescriptions a

B. Beinlich, F. Karsch, A. Peikert

We analyze the latent heat and surface tension at the SU(3) deconfinement phase transition with tree level and tadpole improved Symanzik actions on lattices with temporal extent $N_τ= 3$ and 4 and spatial extent $N_σ/ N_τ= 4$, 6 and 8. In comparison to the standard Wilson action we do find a drastic reduction of cut-off effects already with tree level improv

W. A. Atkinson, J. P. Carbotte

The normal state optical conductivity is calculated for a layered metal with two layers per unit cell coupled through a transverse hopping matrix element $t_\perp$. The optical response involves an interband term in addition to the more familiar intraband term which leads to the usual Drude form. The interband term is only weakly temperature dependent, even

Saverio Moroni, Gaetano Senatore, Stefano Fantoni

We have obtained the one--body density matrix and the momentum distribution $n(p)$ of liquid $^4$He at $T=3D0^o$K from Diffusion Monte Carlo (DMC) simulations, using trial functions optimized via the Euler Monte Carlo (EMC) method. We find a condensate fraction smaller than in previous calculations. Though we do not explicitly include long--range correlation

Jeong-Man Park

We present the existence of the Kosterlitz-Thouless (KT) transition for $n$-atic tangent-plane order on a deformable spherical surface and investigate the development of quasi-long range $n$-atic order and the continuous shape changes below the KT transition in the low temperature limit. The $n$-atic order parameter $ψ= \exp[inΘ]$ describes, respectively, ve

Giuseppe G. N. Angilella, Renato Pucci, Fabio Siringo

Within a BCS-type mean-field approach to the extended Hubbard model, a nontrivial dependence of T_c on the hole content per unit CuO_2 is recovered, in good agreement with the celebrated non-monotonic universal behaviour at normal pressure. Evaluation of T_c at higher pressures is then made possible by the introduction of an explicit dependence of the tight-

M. B. Walker

The spontaneously generated magnetic flux observed by Mannhart et. al. (1996) in 45 degree grain boundaries in YBCO was explained by them in terms of a d-wave superconducting order parameter and grain boundary faceting. This article argues that twin boundaries which contact the grain boundary also play an important role.

C. N. Likos, Saverio Moroni, Gaetano Senatore

We apply density functional theory to study the freezing of superfluid {$^{4}\rm{He}$}, charged bosons and charged fermions at zero temperature. We employ accurate Quantum Monte Carlo data for the linear response function in the uniform phase of these systems, a quantity that has different behavior for large values of the wavevector than previously assumed.

G. Goldoni, F. Rossi, E. Molinari, A. Fasolino

We present a combined theoretical and experimental study of the anisotropy in the optical absorption of V-shaped quantum wires. By means of realistic band structure calculations for these structures, we show that detailed information on the heavy- and light-hole states can be singled out from the anisotropy spectra {\em independently of the electron confinem

Yu-Liang Liu, Zhao-Bin Su, Lu Yu

An extended Anderson model, including screening channels (non-hybridizing, but interacting with the local orbit), is studied within the Anderson-Yuval approach, originally devised for the single-channel Kondo problem. By comparing the perturbation expansions of this model and a generalized resonant level model, the spin-spin correlation functions are calcula

Takashi Kimura, Kazuhiko Kuroki, Hideo Aoki

In order to check whether odd-numbered Tomonaga-Luttinger ladders are dominated by antiferromagnetic correlations associated with gapless spin excitations, correlation functions of the doped three-chain Hubbard model are obtained with the bosonization at the renormalization-group fixed point. The correlation of the singlet superconducting pairing across the

Donghua Xu, Chew Lim Tan

In this paper we address a method to align English-Chinese bilingual news reports from China News Service, combining both lexical and satistical approaches. Because of the sentential structure differences between English and Chinese, matching at the sentence level as in many other works may result in frequent matching of several sentences en masse. In view o

Scott Koranda, Nikolaos Stergioulas, John L. Friedman

Causality alone suffices to set a lower bound on the period of rotation of relativistic stars as a function of their maximum observed mass. That is, by assuming a one-parameter equation of state (EOS) that satisfies v_sound < c and that allows stars with masses as large as the largest observed neutron-star mass, M_sph^max, we find P[ms] > 0.282 + 0.196 ( M_s

D. Sáez, J. V. Arnau

In this paper, we focus our attention on the following question: How well can we recover the power spectrum of the cosmic microwave background from the maps of a given experiment?. Each experiment is described by a a pixelization scale, a beam size, a noise level and a sky coverage. We use accurate numerical simulations of the microwave sky and a cold dark m

A. D. Dolgov

The cosmological evolution of free massless vector or tensor (but not gauge) fields minimally coupled to gravity is analyzed. It is shown that there are some unstable solutions for these fields in De Sitter background. The back reaction of the energy-momentum tensor of such solutions to the original cosmological constant exactly cancels the latter and the ex

R. Turolla, S. Zane, L. Zampieri, L. Nobili

The transport of photons in steady, spherical, scattering flows is investigated. The moment equations are solved analytically for accretion onto a Schwarzschild black hole, taking into full account relativistic effects. We show that the emergent radiation spectrum is a power law at high frequencies with a spectral index smaller (harder spectrum) than in the

M. E. Portnoi, E. I. Rashba

Elementary excitations of incompressible quantum liquids (IQL&#39;s) are anyons, i.e., quasiparticles carrying fractional charges and obeying fractional statistics. To find out how the properties of these quasiparticles manifest themselves in the optical spectra, we have developed the anyon exciton model (AEM) and compared the results with the finite-size da

Jun Li, Gang Tian

We construct Gromov-Witten invariants of general symplectic manifolds.

Anzhong Wang, Henrique P. de Oliveira

An analytical model that represents the collapse of a massless scalar wave packet with continuous self-similarity is constructed, and critical phenomena are found. In the supercritical case, the mass of black holes is finite and has the form $M \propto (p - p^{*})^γ$, with $γ= 1/2$.

Flordivino Basco, Hiroshi Kohno, Hidetoshi Fukuyama, Ganapathy Baskaran

Implication of our recent proposal [J. Phys. Soc. Jpn. 65 (1996) 687] to treat large-amplitude gauge-field fluctuations around the slave-boson mean-field theory for the t-J model has been explored in detail. By attaching gauge flux to spinons and holons and then treating them as free g-on&#39;s which respect the time-reversal symmetry, the optimum exclusion

R. Bijker, F. Iachello, A. Leviatan

We study strong decays of nonstrange baryons by making use of the algebraic approach to hadron structure. Within this framework we derive closed expressions for decay widths in an elementary-meson emission model and use these to analyze the experimental data for N* -> N + pi, N* -> Delta + pi, N* -> N + eta, Delta* -> N + pi, Delta* -> Delta + pi and Delta*

R. M. Cavalcanti, C. A. A. de Carvalho

We present a detailed discussion of some features of quantum mechanical metastability. We analyze the nature of decaying (quasistationary) states and the regime of validity of the exponencial law, as well as decays at finite temperature. We resort to very simple systems and elementary techniques to emphasize subtle aspects of the problem.

P. M. Cowdall, H. Lu, C. N. Pope, K. S. Stelle

We show how toroidally-compactified eleven-dimensional supergravity can be consistently truncated to yield a variety of maximally-supersymmetric ``massive&#39;&#39; supergravities in spacetime dimensions $D\le 8$. The mass terms arise as a consequence of making a more general ansatz than that in usual Kaluza-Klein dimensional reduction, in which one or more

R. N. Mohapatra, Antonio Riotto

We construct realistic supergravity models where supersymmetry breaking arises from the $D$-terms of an anomalous $U(1)$ gauge symmetry broken at the Planck scale. The model has the attractive feature that the gaugino masses, the $A$ and $B$ terms and the mass splittings between the like-charged squarks of the first two generations compared to their average

Onur Tolga Sehitoglu

This study analyses Turkish syntax from an informational point of view. Sign based linguistic representation and principles of HPSG (Head-driven Phrase Structure Grammar) theory are adapted to Turkish. The basic informational elements are nested and inherently sorted feature structures called signs. In the implementation, logic programming tool ALE (Attribut

A. Bragaglia, G. Tessicini, M. Tosi, G. Marconi

We present UBVRI photometry for the old open cluster NGC 6253. From comparison of the observed colour-magnitude diagrams with simulations based on stellar evolutionary models we derive in a self consistent way reddening, distance, and age of the cluster: E(B-V) = 0.23-0.32, (m-M)$_0$ = 10.9$\pm$0.1, metallicity roughly double than solar, and age $\simeq$ 3 G

N. Arbex, U. Ornik, M. Pluemer, B. R. Schlei

We calculate the pi-/pi+ ratio for Pb+Pb at CERN/SPS energies and for Au+Au at BNL/AGS energies using a (3+1) dimensional hydrodynamical model. Without consideration of Coulomb effect an enhancement of this ratio at low mt is found compatible with that observed in these experiments. Our calculations are based on previous (3+1) dimensional hydrodynamical simu

A. Pelster, H. Kleinert

The Duru-Kleinert (DK) method of solving unknown path integrals of quantum mechanical systems by relating them to known ones does not apply to Markov processes since the DK-transform of a Fokker-Planck equation is in general not a Fokker-Planck equation. In this note, we present a significant modification of the method, based again on a combination of path-d

R. Dijkgraaf, G. Moore

We describe a class of topological field theories called ``balanced topological field theories.&#39;&#39; These theories are associated to moduli problems with vanishing virtual dimension and calculate the Euler character of various moduli spaces. We show that these theories are closely related to the geometry and equivariant cohomology of ``iterated supersp

Charles A. Nelson

In a recent paper, eight semileptonic parameters were defined to specify the most general Lorentz-invariant spin correlation functions for tau semileptonic decays. The parameters were physically defined in terms of tau-decay partial-width intensities for polarized final states. This paper studies how these parameters can be simply measured at a tau/charm fac

N. Shibata, K. Ueda, T. Nishino, C. Ishii

The paramagnetic metallic phase of the one-dimensional Kondo lattice model is studied by the density-matrix renormalization- group method. We observe charge and spin Friedel oscillations. They reflect the long range charge-charge and spin-spin correlation functions. The observed oscillations are consistent with a Tomonaga-Luttinger liquid. From the period of

Penny D. Sackett

The Milky Way is often considered to be the best example of a spiral for which the dark matter not only dominates the outer kinematics, but also plays a major dynamical role in the inner galaxy: the Galactic disk is therefore said to be ``sub-maximal.&#39;&#39; This conclusion is important to the understanding of the evolution of galaxies and the viability o

R. Prozorov, M. Konczykowski, B. Schmidt, Y. Yeshurun

We report on measurements of the angular dependence of the irreversibility temperature $T_{irr}(θ) $ in $YBa_2Cu_3O_{7-δ}$ thin films, defined by the onset of a third harmonic signal and measured by a miniature Hall probe. From the functional form of $T_{irr}(θ)$ we conclude that the origin of the irreversibility line in unirradiated films is a dynamic cross

Robert Bluhm, Alan Kostelecky, Bogdan Tudose

The revival structure of Stark wave packets is considered. These wave packets have energies depending on two quantum numbers and are characterized by two sets of classical periods and revival times. The additional time scales result in revival structures different from those of free Rydberg wave packets. We show that Stark wave packets can exhibit fractional

T. A. Brun, N. Gisin, P. F. O&#39;Mahony, M. Rigo

Recently it has been shown that the evolution of open quantum systems may be ``unraveled&#39;&#39; into individual ``trajectories,&#39;&#39; providing powerful numerical and conceptual tools. In this letter we use quantum trajectories to study mesoscopic systems and their classical limit. We show that in this limit, Quantum Jump (QJ) trajectories approach a

A. Pelster, H. Kleinert

Nonrelativistic Newton and Schroedinger equations remain correct not only under holonomic but also under nonholonomic transformations of the spacetime coordinates. Here we study the properties of transformations which are holonomic in the space coordinates while additionally tranforming the time in a path-dependent way. This makes them nonholonomic in spacet

C. Dong, H. Li, G. Mason, P. Montague

The radical $J(V)$ of a vertex operator algebra $V$ is defined to be the subspace of $V$ consisting of vectors $v$ such that the zero mode $o(v)=0$ on $V$ where $o(v)=v_{wt v-1}$ if $v$ is homogeneous. We establish various facts about $o(v),$ including the determination of $J(V)$ which is shown to be essentially equal to $(L(0)+L(-1))V.$

Todd Kapitula

The existence of bright and dark multi-bump solitary waves for Ginzburg-Landau type perturbations of the cubic-quintic Schrodinger equation is considered. The waves in question are not perturbations of known analytic solitary waves, but instead arise as a bifurcation from a heteroclinic cycle in a three dimensional ODE phase space. Using geometric singular p

Silvano Simula

The production of slow nucleons in semi-inclusive deep inelastic electron scattering off nuclei, $A(e, e&#39;N)X$, is analyzed for kinematical conditions accessible at $HERA$ with the $HERMES$ detector. The sensitivity of the semi-inclusive cross section to possible medium-dependent modifications of the nucleon structure function is illustrated.

V. A. Rodin, M. H. Urin

A temperature version of the shell-optical-model approach for describing the low-energy compound-to-compound transitions induced by external single-particle fields is given. The approach is applied to evaluate the mean intensity of the P-odd mixing of nuclear compound states. Unified description for the mixing and electromagnetic transitions allows one to ev

A. Catellani, G. Galli, F. Gygi

The (001) surfaces of cubic SiC were investigated with ab-initio molecular dynamics simulations. We show that C-terminated surfaces can have different c(2x2) and p(2x1) reconstructions, depending on preparation conditions and thermal treatment, and we suggest experimental probes to identify the various reconstructed geometries. Furthermore we show that Si-te

Denny Fliegner, Michael G. Schmidt, Christian Schubert

We discuss the following recent applications of the ``string-inspired&#39;&#39; worldline technique to calculations in quantum electrodynamics: i) Photon splitting in a constant magnetic field, ii) The two-loop Euler-Heisenberg Lagrangian, iii) A progress report on a recalculation of the three-loop QED beta -- function.

Peter van Nieuwenhuizen, Andrew Waldron

We propose a continuous Wick rotation for Dirac, Majorana and Weyl spinors from Minkowski spacetime to Euclidean space which treats fermions on the same footing as bosons. The result is a recipe to construct a supersymmetric Euclidean theory from any supersymmetric Minkowski theory. This Wick rotation is identified as a complex Lorentz boost in a five-dimens

Yu. Makeenko

Matrix models have wide applications in nuclear theory, condensed matter theory and quantum field theory. I discuss supersymmetric extensions of matrix models and their applications to branched polymers, the meander problem, and superstrings in lower dimensions.

Fernando Quevedo, Carlo Trugenberger

We review our recent work on the low-energy actions and the realizations of strong-weak coupling dualities in non-perturbative phases of compact antisymmetric tensor field theories due to p-brane condensation. As examples we derive and discuss the confining string and confining membrane actions obtained from compact vector and tensor theories in 4D. We also

Arundhati Dasgupta, Parthasarathi Majumdar

The leading order correction to the metric of a Schwarzschild black hole, due to the backreaction of infalling fermionic matter fields, is shown to produce a shift of the event horizon such that particles that would constitute Hawking radiation at late retarded times are now trapped. Fermionic field operators associated with infalling and outgoing modes at t

Akira Kokado, Gaku Konisi, Takesi Saito, Kunihiko Uehara

The gauge theory on $M_4\times Z_2$ geometry is applied to the Brans-Dicke(BD) theory, where $M_4$ is the four dimensional space-time and $Z_2$ is a discrete space with two points. This approach had been previously proposed by Konisi and Saito without recourse to noncommutative geometry(NCG). Since our approach is geometrically simpler and clearer than NCG,

Hai-Yang Cheng

Form factors for $P\to P$ and $P\to V$ transitions due to the valence-quark configuration are calculated directly in the physical time-like range of momentum transfer within the light-front quark model. It is pointed out that the Bauer-Stech-Wirbel type of light-front wave function fails to give a correct normalization for the Isgur-Wise function at zero rec

Hai-Yang Cheng

Weak current-induced baryonic form factors at zero recoil are evaluated in the rest frame of the heavy parent baryon using the nonrelativistic quark model. Contrary to previous similar work in the literature, our quark model results do satisfy the constraints imposed by heavy quark symmetry for heavy-heavy baryon transitions. Assuming a dipole $q^2$ behavior

Debajyoti Choudhury

A very light gluino ($m_{\tilde g} \lsim 2 \gev$) is still consistent with experimental data and is attractive from a theoretical standpoint. This has been shown to lead to a small gluino content of the proton. We use this effect to demonstrate that such a light gluino could lead to a striking enhancement, at Tevatron, of monojets accompanied by large missin

G. Alves, E. Levin, A. Santoro

We show that the cross section of the diffractive production of $b \bar b$ can be described as the sum of two contributions: the first is proportional to the probability of finding a small size $b \bar b$ color dipole in the fast hadron wave function before the interaction with a target, while the second is the $b \bar b$-production after or during the inter