October 1995 arXiv papers — page 7

M. C. Gonzalez-Garcia, F. Vannucci, J. Castromonte

We discuss the possibility of searching for anomalous magnetic transitions of neutrinos in the CERN beam induced by the absorption or emission of low-energy photons in a high-quality resonant cavity such as the LEP radio-frequency cavities. With the attainable sensitivities of the present CERN neutrino detectors, this experiment would impose strong limits on

Peter A. Henning

The problem of thermalization of a quark -- gluon plasma is addressed in the framework of thermal field theory. Within a simple approximation, the full quantum relaxation problem is solved and compared to the Boltzmann solution. Memory effects and a slowdown of the relaxation process are the results, they can be partially described by using a generalized kin

Per Elmfors

Dispersion relations for fermions at high temperature and in a background magnetic field are calculated in two different ways. First from a straightforward one-loop calculation where, in the weak field limit, we find an expression closely related to the standard dispersion relations in the absence of the magnetic field. Secondly, we derive the dispersion rel

R. Foot, R. R. Volkas

We discuss a simple predictive solution to the solar neutrino problem based on maximal vacuum neutrino oscillations. The solution can be motivated by the exact parity symmetric model which predicts that the neutrino mass eigenstates are maximal mixtures of ordinary and mirror weak eigenstates (if neutrinos are massive). We show that this proposed solution to

Shinji Ejiri

We studied a behavior of monopole currents in the high temperature (deconfinement) phase of abelian projected finite temperature SU(2) QCD in maximally abelian gauge. Wrapped monopole currents closed by periodic boundary play an important role for the spatial string tension which is a non-perturbative quantity in the deconfinement phase. The wrapped monopole

The SLD Collaboration

We present the first measurement of the correlation between the $Z^0$ spin and the three-jet plane orientation in polarized $Z^0$ decays into three jets in the SLD experiment at SLAC utilizing a longitudinally polarized electron beam. The CP-even and T-odd triple product $\vec{S_Z}\cdot(\vec{k_1}\times \vec{k_2})$ formed from the two fastest jet momenta, $\v

Darío Núñez, Hernando Quevedo, Daniel Sudarsky

We show that in all theories in which black hole hair has been discovered, the region with non-trivial structure of the non-linear matter fields must extend beyond $3/ 2$ the horizon radius, independently of all other parameters present in the theory. We argue that this is a universal lower bound that applies in every theory where hair is present. This {\it

Sergio A. Hojman, Darío Núñez

The purpose of this Comment is to show that the solutions to the zero energy Schrödinger equations for monomial central potentials discussed in a recently published Letter, may also be obtained from the corresponding free particle solutions in a straight forwardly way, using an algorithm previously devised by us. New solutions to the zero energy Schrödinger

P. Hajicek, C. J. Isham

The perennial formalism is applied to the real, massive Klein-Gordon field on a globally-hyperbolic background space-time with compact Cauchy hypersurfaces. The parametrized form of this system is taken over from the accompanying paper. Two different algebras ${\cal S}_{\text{can}}$ and ${\cal S}_{\text{loc}}$ of elementary perennials are constructed. The el

A. O. Barvinsky, A. Yu. Kamenshchik

Quantum origin of the early inflationary Universe from the no-boundary and tunnelling quantum states is considered in the one-loop approximation of quantum cosmology. A universal effective action algorithm for the distribution function of chaotic inflationary cosmologies is derived for both of these states.The energy scale of inflation is calculated by findi

Rafael D. Sorkin, Madhavan Varadarajan

We derive the so-called first law of black hole mechanics for variations about stationary black hole solutions to the Einstein--Maxwell equations in the absence of sources. That is, we prove that $δM=κδA+ωδJ+VdQ$ where the black hole parameters $M, κ, A, ω, J, V$ and $Q$ denote mass, surface gravity, horizon area, angular velocity of the horizon, angular mom

J. Fernando Barbero, Michael P. Ryan,

The Ashtekar variables have been use to find a number of exact solutions in quantum gravity and quantum cosmology. We investigate the origin of these solutions in the context of a number of canonical transformations (both complex and real) of the basic Hamiltonian variables of general relativity. We are able to present several new solutions in the minisupers

A. H. Castro Neto, Matthew P. A. Fisher

We study the dynamics of a heavy particle of mass $M$ moving in a one-dimensional repulsively interacting Fermi gas. The Fermi gas is described using the Luttinger model and bosonization. By transforming to a frame co-moving with the heavy particle, we map the model onto a generalized ``quantum impurity problem". A renormalization group calculation revea

R. E. Goldstein, P. Nelson, T. Powers, U. Seifert

Recently Bar-Ziv and Moses discovered a dynamical shape transformation induced in cylindrical lipid bilayer vesicles by the action of laser tweezers. We develop a hydrodynamic theory of fluid bilayers in interaction with the surrounding water and argue that the effect of the laser is to induce a sudden tension in the membrane. We refine our previous analysis

Daniela Pfannkuche, Sergio E. Ulloa

Tunneling of electrons traversing a few-electron quantum dot is strongly influenced by the Coulomb interaction leading to Coulomb blockade effects and single-electron tunneling. We present calculations which demonstrate that correlations between the electrons cause a strong suppression of most of the energetically allowed tunneling processes involving excite

A. Georges, G. Kotliar, W. Krauth, M. J. Rozenberg

We review the dynamical mean-field theory of strongly correlated fermion systems which is based on a mapping of lattice models onto quantum impurity models subject to a self-consistency condition. This mapping is exact in the limit of large lattice coordination (or infinite spatial dimensions). This method can be used for the determination of phase diagrams

Eric M. Kramer, Alexander E. Lobkovsky

Using high-resolution digital recordings, we study the crackling sound emitted from crumpled sheets of mylar as they are strained. These sheets possess many of the qualitative features of traditional disordered systems including frustration and discrete memory. The sound can be resolved into discrete clicks, emitted during rapid changes in the rough conforma

Tsuyoshi Hondou, Yasuji Sawada

Dynamical behaviors of a dissipative particle in a periodic potential subject to chaotic noise are reported. We discovered a macroscopic symmetry breaking effect of chaotic noise on a dissipative particle in a multi-stable systems emerging, even when the noise has a uniform invariant density with parity symmetry and white Fourier spectrum. The broken parity

Robert Rutledge, Lori Lubin, Walter Lewin, Brian Vaughan

We present an X-ray fast-timing and spectral analysis of the type II bursts and the persistent emission (PE) of the Rapid Burster observed with the EXOSAT Medium-Energy Instrument. The Hardness-Intensity and Color-Color Diagrams of the Rapid Burster are somewhat different from those of the majority of other low-mass X-ray binaries, which fall into two distin

David Merritt

Recent results on chaos in triaxial galaxy models are reviewed. Central mass concentrations like those observed in early-type galaxies -- either stellar cusps, or massive black holes -- render most of the box orbits in a triaxial potential stochastic. Typical Liapunov times are 3-5 crossing times, and ensembles of stochastic orbits undergo mixing on time sca

L. Ciotti, S. Pellegrini

The global energy budget of the hot gas flows in early-type galaxies is used to explain the recent observational results that S0 galaxies have lower mean X-ray luminosity $L_X$ per unit optical luminosity $L_B$ than do ellipticals. This could be explained with a higher heat input or with a lower gravitational energy (all per unit gas mass), at fixed $L_B$. T

Roger Coziol

In this paper, we use different luminosity ratios to trace the histories of star formation of two different kinds of starburst galaxies: HII galaxies and starburst nucleus galaxies (SBNGs). The mean star formation rates (SFRs) for these galaxies is comparable, and compatible with a near constant star formation over a few Gyr period. We have also found an int

Shoji Kato, Marek A. Abramowicz, Xingming Chen

Thermal instability is examined for advection-dominated one-temperature accretion disks. We consider axisymmetric perturbations with short wavelength in the radial direction. The viscosity is assumed to be sufficiently small for the vertical hydrostatic balance to hold in perturbed states. The type of viscosity is given either by the $α$-viscosity or by a di

J. -P. Lasota, M. A. Abramowicz, X. Chen, J. Krolik

The mass of the central black hole in the active galaxy NGC 4258 (M106) has been measured to be $M=3.6\times10^7\Msun$ (Miyoshi et al. 1995). The Eddington luminosity corresponding to this mass is $L_E=4.5\times10^{45}$ erg s$^{-1}$. By contrast the X-ray luminosity of the nucleus of NGC 4258 between $2-10$ keV is $(4\pm 1)\times10^{40}~{\rm erg\,s^{-1}}$ wh

K. F. Gunn, P. A. Thomas

We review the theories and observations which together have led to the concept of the Baryon Catastrophe: observations of the baryon fraction on the scale of clusters of galaxies appear to be at least three times as high as the universal baryon fraction predicted by the theory of primordial nucleosynthesis in a flat, $Ω_0 = 1$, universe. We investigate wheth

Sergey S. Kurennoy

The electric and magnetic polarizabilities of an aperture are its important characteristics in the theory of aperture coupling and diffraction of EM waves. The beam coupling impedances due to a small discontinuity on the chamber wall of an accelerator can also be expressed in terms of the polarizabilities of the discontinuity. The polarizabilities are geomet

Y. Schröder, H. Schulz

A Feynman-Jensen version of the thermal variational principle is applied to hot gauge fields, Abelian as well as non-Abelian: scalar electrodynamics (without scalar self-coupling) and the gluon plasma. The perturbatively known self-energies are shown to derive by variation from a free quadratic (''Gaussian'') trial Lagrangian. Independence of

Nathan Berkovits, Warren Siegel

Two-dimensional sigma models are defined for the new manifestly spacetime supersymmetric description of four-dimensional compactified superstrings. The resulting target-superspace effective action is constrained by the way the spacetime dilaton couples to the worldsheet curvature: For the heterotic superstring, the worldsheet curvature couples to the real pa

Claudio de C. Chamon, Christopher Mudry, Xiao-Gang Wen

The computation of multifractal scaling properties associated with a critical field theory involves non-local operators and remains an open problem using conventional techniques of field theory. We propose a new description of Gaussian field theories in terms of random Cantor sets and show how universal multifractal scaling exponents can be calculated. We us

Ron Donagi, Edward Witten

The Coulomb branch of $N=2$ supersymmetric gauge theories in four dimensions is described in general by an integrable Hamiltonian system in the holomorphic sense. A natural construction of such systems comes from two-dimensional gauge theory and spectral curves. Starting from this point of view, we propose an integrable system relevant to the $N=2$ $SU(n)$ g

A. N. Kuznetsov, P. G. Tinyakov

We calculate numerically the probability $\exp[ {1\overλ} F(E/E_{sph},N/N_{sph})]$ of the false vacuum decay in the massive four-dimensional $-λϕ^4$ model from multiparticle initial states with fixed number of particles $N$ and energy $E$ greater than the height of the barrier $E_{sph}$. We find that at $E\lsim 3E_{sph}$ and $N\lsim 0.4N_{sph}$ the decay is

W. Bietenholz, U. -J. Wiese

We use perturbation theory to construct perfect lattice actions for quarks and gluons. The renormalized trajectory for free massive quarks is identified by blocking directly from the continuum. We tune a parameter in the renormalization group transformation such that for 1-d configurations the perfect action reduces to the nearest neighbor Wilson fermion act

Mario E. Gomez, Haim Goldberg

We analyze the scalar lepton mass matrices in a supersymmetric SO(10) grand unified model with soft SUSY breaking terms generated at Planck scale and a Georgi-Jarslkog Yukawa texture at GUT scale induced by higher dimensional operators. This model predicts lepton flavor violation. The predictive features of the Georgi-Jarlskog texture are used to estimate br

Brett van de Sande, Matthias Burkardt

We propose the tube model as a first step in solving the bound state problem in light-front QCD. In this approach we neglect transverse variations of the fields, producing a model with 1+1 dimensional dynamics. We then solve the two, three, and four particle sectors of the model for the case of pure glue SU(3). We study convergence to the continuum limit and

P. J. Mulders, R. D. Tangerman

We present the results of the tree-level calculation of deep-inelastic leptoproduction, including polarization of target hadron and produced hadron. We also discuss the dependence on transverse momenta of the quarks, which leads to azimuthal asymmetries for the produced hadrons.

A. H. Chamseddine

We show that non-chiral $N=2$ supergravity in ten-dimensions admits a family of dual actions where the one-form, two-form or three-form is replaced by the seven-form, six-form or five-form respectively. The dual actions and supersymmetry transformations are given.

J. Leon

The equations of transient stimulated Raman scattering on the finite interval are solved by the spectral transform method on the semi-line. As the problem has a free end, the pump and Stokes output at finite distance can be constructed as the solution of a linear Cauchy-Green integral equation.

M. Kenmoku, K. Otsuki, K. Shigemoto, K. Uehara

We have studied various classical solutions in $R^2$ cosmology. Especially we have obtained general classical solutions in pure $R^2$\ cosmology. Even in the quantum theory, we can solve the Wheeler-DeWitt equation in pure $R^2$\ cosmology exactly. Comparing these classical and quantum solutions in $R^2$\ cosmology, we have studied the problem of time in gen

Yoshinobu Kuramashi

We report on our recent study of flavor singlet matrix elements calculated with the wall source method without gauge fixing. Results are presented for the mass difference between $η^{\prime}$ and pseudoscalar octet mesons, the $π$-N $σ$ term and the proton axial vector matrix elements. An exploratory calculation of the N-N scattering lengths is also discusse

Thierry Dauxois, Stephan Fauve, Laurette Tuckerman

The stability of periodic arrays of Mallier-Maslowe or Kelvin-Stuart vortices is discussed. We derive with the energy-Casimir stability method the nonlinear stability of this solution in the inviscid case as a function of the solution parameters and of the domain size. We exhibit the maximum size of the domain for which the vortex street is stable. By adapti

Marios A. Kagarlis, Vladimir F. Dmitriev

We propose a theory which exploits the charge-exchange reactions ($^3$He,$^3$H$π^+$) and (p,n$π^+$) as effective sources of virtual pions. We consider processes in which the creation of virtual pions is followed by conventional coupled-channel pion scattering to discrete nuclear states. This picture allows us to incorporate successful theories of pion scatte

A. N. Artemyev, V. M. Shabaev, V. A. Yerokhin

The relativistic nuclear recoil corrections to the energy of the $2p_{\frac{3}{2}}$ state of hydrogen-like and the $(1s)^{2}2p_{\frac{3}{2}}$ state of high $Z$ lithium-like atoms in all orders in $αZ$ are calculated. The calculations are carried out using the B-spline method for the Dirac equation. For low $Z$ the results of the calculation are in good agree

K. Svozil, R. R. Zapatrin

We compare the two approaches to the empirical logic of automata. The first, called partition logic (logic of microstatements), refers to experiments on individual automata. The second one, the logic of simulation (logic of macrostatements), deals with ensembles of automata.

N. Hambli, J. Michelson, R. T. Sharp

A new set of polynomial states (to be called character states) are derived for $Sp(4)$ reduced to its $SU(2) \times U(1)$ subgroup, and the relevant generator matrix elements are evaluated. The group--subgroup in question is that of the seniority model of nuclear physics.

W. M. Alberico, M. B. Barbaro, A. Molinari

A few aspects of the $Λ$ mesonic and non-mesonic decay in nuclei are shortly addressed.

A. W. Schreiber, R. Rosenfelder

We investigate a relativistic quantum field theory in the particle representation using a non-perturbative variational technique. The theory is that of two massive scalar particles, `nucleons' and `mesons', interacting via a Yukawa coupling. We calculate the general Euclidean Green function involving two external nucleons and an arbitrary number of e

H. Oberhummer, W. Balogh, V. D. Efros, H. Herndl

An introduction to nucleosynthesis, the creation of the elements in the big bang, in interstellar matter and in stars is given. The two--step process $^4$He(2n,$γ$)$^6$He and the reverse photodisintegration $^6$He($γ$,2n)$^4$He involving the halo nucleus $^6$He could be of importance in the $α$--process in type--II supernovae. The reaction rates for the abov

C. Rambaut, K. H. Oh, H. Jaffrezic, J. Kohanoff

Energy storage and release in dielectric materials can be described on the basis of the charge trapping mechanism. Most phenomenological aspects have been recently rationalized in terms of the space charge model~\cite{blaise,blaise1}. Dynamical aspects are studied here by performing Molecular Dynamics simulations. We show that an excess electron introduced i

Pradipta Bandyopadhyay, Sudeshna Basu

In this work, we introduce a new Asymptotic Norming Property (ANP) which lies between the strongest and weakest of the existing ones, and obtain isometric characterisations of it. The corresponding w*-ANP turns out to be equivalent on the one hand, to Property $(V)$ introduced by Sullivan, and to a ball separation property on the other. We also study stabili

G. T. Ter-Kazarian

The question that guides our discussion is "how did the geometry and particles come into being?" To explore this query we suggest the theory of goyaks, which reveals the primordial deeper structures underlying fundamantal concepts of contemporary physics. It address itself to the question of the prime-cause of origin of geometry and basic concepts of

A. Fabbri, J. G. Russo

A one-parameter class of simple models of two-dimensional dilaton gravity, which can be exactly solved including back-reaction effects, is investigated at both classical and quantum levels. This family contains the RST model as a special case, and it continuously interpolates between models having a flat (Rindler) geometry and a constant curvature metric wit

N. Fleury, M. Rausch de Traubenberg

A group theory justification of one dimensional fractional supersymmetry is proposed using an analogue of a coset space, just like the one introduced in $1D$ supersymmetry. This theory is then gauged to obtain a local fractional supersymmetry {\it i.e.} a fractional supergravity which is then quantized {\it à la Dirac} to obtain an equation of motion for a p

Khazret S. Nirov, Valery A. Rubakov

Emission of hard microscopic string (graviton) by an excited macroscopic string may be viewed as a model of branching of a $(1+1)$-dimensional baby universe off large parent one. We show that, apart from a trivial factor, the total emission rate is not suppressed by the size of the macroscopic string. This implies unsuppressed loss of quantum coherence in $(

Lubos Motl

In this paper some quite simple examples of applications of the zeta-function regularization to superstring theories are presented. It is shown that the Virasoro anomaly in the BRST formulation of (super)strings can be directly computed from the original expressions of the operators as well as normal ordering constants and masses of ground levels. Hawking&#3

Konstadinos Sfetsos

The interplay between T-duality and supersymmetry in string theory is explored. It is shown that T-duality is always compatible with supersymmetry and simply changes a local realization to a non-local one and vice versa. Non-local realizations become natural using classical parafermions of the underlying conformal field theory. Examples presented include hyp

M. Koseki, M. Sato, R. Endo

Yokoyama's gaugeon formalism is knwon to admit $q$-number gauge transformation. We introduce BRST symmetries into the formalism for the Yang-Mills gauge field. Owing to the BRST symmetry, Yokoyama's physical subsidiary conditions are replaced by a single condition of the Kugo-Ojima type. Our physical subsidiary condition is invariant under the $q$-nu

Mirjam Cvetic, Donam Youm

We summarize the results for four-dimensional Bogomol'nyi-Prasad- Sommerfield (BPS) saturated dyonic black hole solutions arising in the Kaluza-Klein sector and the three-form field sector of the eleven-dimensional supergravity on a seven-torus. These black hole solutions break $3\over 4$ of $N=8$ supersymmetry, fill out the multipletes of $U$-duality gr

Ken Sasaki

It is proposed to use the pinch technique (PT) to obtain the gauge-independent thermal $β$ function in a hot Yang-Mills gas. Calculations of the thermal $β$ function are performed at one-loop level in four different gauges, (i) the background field method with an arbitrary gauge, (ii) the Feynman gauge, (iii) the Coulomb gauge, and (iv) the temporal axial ga

J. Hisano, T. Moroi, K. Tobe, M. Yamaguchi

Various lepton-flavor violating (LFV) processes in the supersymmetric standard model with right-handed neutrino supermultiplets are investigated in detail. It is shown that large LFV rates are obtained when $\tan β$ is large. In the case where the mixing matrix in the lepton sector has a similar structure as the Kobayashi-Maskawa matrix and the third-generat

Toby Falk, Keith A. Olive, Leszek Roszkowski, Mark Srednicki

We consider the Minimal Supersymmetric Standard Model (MSSM) without imposing relations on the superpartner masses that arise in grand unified theories. Given an arbitrary pattern of superpartner masses (consistent with experimental constraints), it may happen that the scalar potential is actually unstable, even though all scalar masses-squared are positive

Nimai C. Mukhopadhyay, J. -F. Zhang, M. Benmerrouche

Using the recent precise measurements of eta photopro- duction in proton and deuteron targets, we extract the ratio of the helicity amplitudes A^n_1/2 / A^p_1/2, for the excitation of N^*(1535), in the effective Lagrangian approach, It is fairly model-independent, free from the final-state interaction effects, and negative as predicted by the quark models. W

Daniel Ng, John N. Ng

The electric dipole moment of the electron, $d_e$, is known to vanish up to thre e-loops in the standard model with massless neutrinos. However, if neutrinos are massive Majorana particles, we obtain the result that $d_e$ induced by leptonic CKM mechanism is non-vanishing at two-loop order, and it applies to all massive Majorana neutrino models.

X. Ji, J. Tang, P. Hoodbhoy

In analogy to the Altarelli-Parisi equation for the quark and gluon helicity contributions to the nucleon spin, we derive an evolution equation for the quark and gluon orbital angular momenta. The solution of the combined equations yields the asymptotic fractions of the nucleon spin carried by quarks and gluons: $3n_f/(16+3n_f)$ and $16/(16+3n_f)$, respectiv

H. Jallouli, H. Sazdjian

The relativistic fermion-antifermion bound state vector potential of constraint theory is calculated, in perturbation theory, by means of the Lippmann-Schwinger type equation that relates it to the scattering amplitude. Leading contributions of n-photon exchange diagrams are calculated in an approximation scheme that adapts eikonal approximation to the bound

Werner Bernreuther, Arnd Brandenburg, Peter Uwer

We investigate the prospects to observe effects of transverse polarization of top quarks in $pp,p\bar{p}\to t\bar{t}X$. QCD absorptive parts generate a polarization of top quarks and antiquarks transverse to the production plane in the partonic processes $q\bar{q}\to t\bar{t}$ and $gg\to t\bar{t}$, which reaches values of a few percent. These perturbative QC

Frank Cuypers

We analyze the incidence on polarized $e^-e^-$ scattering of the trilinear and quartic anomalous gauge couplings which arise in the realm of a non-linear realization of electroweak symmetry breaking.

J. M. LoSecco, T. Adams, J. M. Bishop, N. M. Cason

The recent search for non $q \bar{q}$ mesons in $π^{-}p$ interactions at Brookhaven National Laboratory is summarized. Many final states such as $ηπ$, $η' π^{-}$, $a_{0} π$, $f_{1} π$, $a_{2} π$, $b_{1} π$, which are favored decay modes of exotics, are under investigation.

N. Koch, M. Kolander, H. Kolanoski, T. Siegmund

A fast second level trigger has been developed for the ARGUS experiment which recognizes tracks originating from the interaction region. The processor compares the hits in the ARGUS Micro Vertex Drift Chamber to 245760 masks stored in random access memories. The masks which are fully defined in three dimensions are able to reject tracks originating in the wa

John D. Anderson, Mark Gross, Kenneth L. Nordtvedt, Slava G. Turyshev

The Earth, Mars, Sun, Jupiter system allows for a sensitive test of the strong equivalence principle (SEP) which is qualitatively different from that provided by Lunar Laser Ranging. Using analytic and numerical methods we demonstrate that Earth-Mars ranging can provide a useful estimate of the SEP parameter $η$. Two estimates of the predicted accuracy are d

P. Hajicek, C. J. Isham

We study the real, massive Klein-Gordon field on a $C^\infty$ globally-hyperbolic background space-time with compact Cauchy hypersurfaces. In particular, the parametrization of this system as initiated by Dirac and Kuchař is put on a rigorous basis. The discussion is focussed on the structure of the set of spacelike embeddings of the Cauchy manifold into the

Richard Montgomery

Suppose that the initial triangle formed by the three moving masses of the three-body problem is similar to the triangle formed at some later time. We derive a simple integral formula for the overall rotation relating the two triangles. The formula is based on the fact that the space of similarity classes of triangles forms a two-sphere which we call the sha

Leon Balents, Matthew P. A. Fisher

In layered samples which exhibit a bulk quantum Hall effect (QHE), a two-dimensional (2d) surface ``sheath" of gapless excitations is expected. These excitations comprise a novel 2d chiral quantum liquid which should dominate the low temperature transport along the field (z-axis). For the integer QHE, we show that localization effects are completely abse

Samuel Moukouri, Laurent G. Caron

We compute the magnetic structure factor, the singlet correlation function and the momentum distribution of the one-dimensional Kondo lattice model at the density $ρ=0.7$. The density matrix-renormalization group method is used. We show that in the weak-coupling regime, the ground state is paramagnetic. We argue that a Luttinger liquid description of the mod

J. H. Oaknin, L. Martin-Moreno, C. Tejedor

We present an analysis of spin-textures in Quantum Hall droplets, for filling factors $ν\simeq 1$. Analytical wavefunctions with well defined quantum numbers are given for the low-lying states of the system which result to be either bulk skyrmions or edge spin excitations. We compute dispersion relations and study how skyrmions become ground states of the Qu

R. K. Bhaduri, M. V. N. Murthy, M. K. Srivastava

Using the Thomas-Fermi approximation, we show that an interacting two dimensional electron gas may be described in terms of fractional exclusion statistics at zero and finite temperatures when the interaction has a short-range component. We argue that a likely physical situation for this phenomenon to occur may exist in two dimensional quantum dots.

F. F. Assaad, M. Imada

We use Quantum Monte Carlo methods to determine $T=0$ Green functions, $G(\vec{r}, ω)$, on lattices up to $16 \times 16$ for the 2D Hubbard model at $U/t =4$. For chemical potentials, $μ$, within the Hubbard gap, $ |μ| < μ_c$, and at {\it long} distances, $\vec{r}$, $G(\vec{r}, ω= μ) \sim e^{ -|\vec{r}|/ξ_l}$ with critical behavior: $ξ_l \sim | μ- μ_c |^{-ν}

R. Benzi, L. Biferale, E. Trovatore

In this paper we study a new class of shell models, defined in terms of two complex dynamical variables per shell, transporting positive and negative helicity respectively. The dynamical equations are derived from a decomposition into helical modes of the velocity Fourier components of Navier-Stokes equations (F. Waleffe, Phys. Fluids A {\bf 4}, 350 (1992)).

Thierry Dombre, Jean-Louis Gilson

The multiscaling properties of the mixed Obukhov-Novikov shell model of turbulence are investigated numerically and compared with those of the complex GOY model, mostly studied in the recent years. Two types of generic singular fluctuations are identified~: first, self-similar solutions propagating from large to small scales and building up intermittency, se

J. D. Anderson, S. G. Turyshev, S. W. Asmar, M. K. Bird

We review the results from {\it Mariner 10} regarding Mercury&#39;s gravity field and the results from radar ranging regarding topography. We discuss the implications of improving these results, including a determination of the polar component, as well as the opportunity to perform relativistic gravity tests with a future {\it Mercury Orbiter}. With a spacec

Jack Baldwin, Gary Ferland, Kirk Korista, Dima Verner

The similarity of quasar line spectra has been taken as an indication that the emission line clouds have preferred parameters, suggesting that the environment is subject to a fine tuning process. We show here that the observed spectrum is a natural consequence of powerful selection effects. We computed a large grid of photoionization models covering the wide

A. Mathieu, H. Dejonghe, X. Hui

Photometry and kinematics of the giant elliptical galaxy NGC~5128 (Centaurus~A) based on planetary nebulae observations (Hui~\etal 1995) are used to build dynamical models which allow us to infer the presence of a dark matter halo. To this end, we apply a Quadratic Programming method. Constant mass-to-light ratio models fail to reproduce the major axis veloc

R. A. Malaney, B. Chaboyer

Using the redshift evolution of the neutral hydrogen density, as inferred from observations of damped Ly$α$ clouds, we calculate the evolution of star formation rates and elemental abundances in the universe. For most observables our calculations are in rough agreement with previous results based on the instantaneous re-cycling approximation (IRA). However,

M. Cvetic, A. A. Tseytlin

We show that a four-parameter generating solution for a general class of four-dimensional, spherically-symmetric, static, dyonic BPS saturated solutions of leading-order effective equations of toroidally compactified heterotic or type II superstring theory are exact string solutions. The corresponding ten-dimensional background defines a conformal sigma-mode

J. Riera, S. Koval, D. Poilblanc, F. Pantigny

Pair breaking mechanisms by impurities are investigated in the two-dimensional t-J model by exact diagonalization techniques. Analysis of binding energies, pairing correlations, dynamical spin and pair susceptibilities shows that non-magnetic impurities are more effective in suppressing pairing than magnetic ones in agreement with experimental studies of Zn-

C. Bachas, C. Fabre, T. Yanagida

We argue that moduli in the adjoint representation of the standard- model gauge group are a natural feature of superstring models, and that they can account for the apparent discrepancy between the string and unification scales.

Leonid Frankfurt, Mark Strikman

We argue that current data on nuclear shadowing confirm expectations of the color singlet models of nuclear shadowing. We demonstrate that unitarity constrains require nuclear shadowing for gluons to be very significant already for $x \le 10^{-3}$ . Physics of coherent diffraction production of vector mesons off light nuclei is also discussed.

Luca Salasnich

The presence of chaos and quantum chaos is shown in two different nuclear systems. We analyze the chaotic behaviour of the classical SU(2) Yang--Mills--Higgs system, and then we study quantum chaos in the nuclear shell model calculating the spectral statistics of $A=46$--$50$ atomic nuclei.

Mladen Damjanović, Zvonko Marić

The space-time features of the relativistic dynamics are analyzed in the framework of the time dependent propagator theory. The adiabatic hypothesis is substituted by the disturbative adiabatic hypothesis, resulting with the corresponding space-time regionalization of scattering processes. The other kind of generalization introduces forms of the propagator t

Mirna Džamonja, Saharon Shelah

Suppose that lambda = mu^+. We consider two aspects of the square property on subsets of lambda. First, we have results which show e.g. that for aleph_0 <= kappa =cf (kappa)< mu, the equality cf([mu]^{<= kappa}, subseteq)= mu is a sufficient condition for the set of elements of lambda whose cofinality is bounded by kappa, to be split into the union of mu set

Saharon Shelah, Otmar Spinas

A Gross space is a vector space E of infinite dimension over some field F, which is endowed with a symmetric bilinear form Phi:E^2 -> F and has the property that every infinite dimensional subspace U subseteq E satisfies dim U^perp < dim E. Gross spaces over uncountable fields exist (in certain dimensions). The existence of a Gross space over countable or fi

Avinash Khare

Complete energy spectrum is obtained for the quantum mechanical problem of N one dimensional equal mass particles interacting via potential $$V(x_1,x_2,...,x_N) = g\sum^N_{i < j}{1\over (x_i-x_j)^2} - {α\over \sqrt{\sum_{i < j} (x_i-x_j)^2}}$$ Further, it is shown that scattering configuration, characterized by initial momenta $p_i (i=1,2,...,N)$ goes over i

Yu-kui Zhou

The functional relations of the transfer matrices of fusion hierachies for six- and eight-vertex models with open boundary conditions have been presented in this paper. We have shown the su($2$) fusion rule for the models with more general reflection boundary conditions, which are represented by off-diagonal reflection matrices. Also we have discussed some p

T. S. Evans

I study how to apply relativistic quantum field theory to condensed matter systems. The motivation for this is examined and then two separate elements are considered. First we identify the precise relationship between relativistic and non-relativistic fields. Second we consider the need for a chemical potential and how one includes this in static and dynamic

N. L. Ter-Isaakyan

The spin dependent deuteron structure functions are investigated in the relativistic model of deuteron. It is shown that the deuteron structure function $g_{2}(X)$ can be considered properly only in the infinite momentum frame where the virtual photon has pure transverse components ($q_{0}=-q_{3}\rightarrow 0$ at $ P\rightarrow \infty $), whereas in the conv

Leonid Frankfurt, Mark Strikman

Coherence phenomena, and the non-universality of parton structure of the effective Pomeron are explained. New hard phenomena directly calculable in QCD such as diffractive electroproduction of states with $M^2\ll Q^2$ as well as new options to measure the light-cone wave functions of various hadrons are considered. An analogue of Bjorken scaling is predicted

Malgorzata E. Stys, Stefan S. Zemke

The main aim of translation is an accurate transfer of meaning so that the result is not only grammatically and lexically correct but also communicatively adequate. This paper stresses the need for discourse analysis the aim of which is to preserve the communicative meaning in English--Polish machine translation. Unlike English, which is a positional languag

C. S. Kochanek

We present limits on the cosmological constant from the statistics of gravitational lenses using newly completed quasar surveys, new lens data, and a range of lens models. The formal limit is $λ_0 < 0.66$ at 95\% confidence in flat cosmologies, including the statistical uncertainties in the number of lenses, galaxies, quasars, and the parameters relating gal

C. S. Kochanek, G. B. Rybicki

The deprojection of axisymmetric density distributions is generally indeterminate to within the addition of certain axisymmetric distributions (konus densities) that are invisible in projection. The known class of konus densities is expanded considerably here through the introduction of {\em semikonus functions}. These functions are closed with respect to mu

C. S. Kochanek

Nearly singular isothermal mass distributions with small core radii are consistent with stellar dynamics, lens statistics, and lens models as a model for E/S0 galaxies. Models like the de Vaucouleurs model with a constant mass-to-light ratio are not. While the isothermal distributions are probably an oversimplification, E/S0 galaxies (at least in projection)

C. S. Kochanek

Quantitative estimates of lensing probabilities must be self-consistent. In particular, for asymptotically isothermal models: (1) using the $(3/2)^{1/2}$ correction for the velocity dispersion overestimates the expected number of lenses by 150\% and their average separations by 50\%, thereby introducing large cosmological errors; (2) when a core radius is ad