April 1999 arXiv papers — page 21

F. Combes

The currently discussed theories of bulge formation are reviewed, including the primordial scenario, where bulges form rapidly and then accrete disks, the secular scenario, where bulges are formed by dynamical evolution of disks through bars and galaxy interactions, and some combinations of both, where formation of bulges and disks are more continuous and in

E. Iodice, M. D'Onofrio, M. Capaccioli

We outline the results of a two-dimensional (2D) fit of the light distribution of early-type galaxies belonging to a complete volume-limited sample, and briefly discuss the significant correlations among the structural parameters. In particular we reconfirm that the lack of structural homology is likely a characteristic of hot stellar systems.

D. Galli, S. Lizano, Z. -Y. Li, F. C. Adams

We investigate the equilibrium properties of self-gravitating magnetized clouds with polytropic equations of state with negative index n. In particular, we consider scale-free isopedic configurations that have constant dimensionless spherical mass-to-flux ratio lambda_r and that may constitute ``pivotal'' states for subsequent dynamical collapse to f

Ian B. Thompson, Janusz Kaluzny, Wojtek Pych, Wojtek Krzeminski

We present the results of a photometric survey for variable stars in the field of the nearby globular cluster NGC 6752. The cluster was monitored in 1996 and 1997 for a total of 54 hours with 3 different CCD cameras mounted on the 1.0-m Swope telescope. Eleven new variables were identified: 3 SX Phe stars, 7 contact binaries and 1 candidate detached eclipsin

P. A. Henning, L. Staveley-Smith, R. C. Kraan-Korteweg, E. M. Sadler

The HI Parkes Zone of Avoidance Survey is a 21 cm blind search with the multibeam receiver on the 64-m radiotelescope, looking for galaxies hidden behind the southern Milky Way. The first, shallow (15 mJy rms) phase of the survey has uncovered 107 galaxies, two-thirds of which were previously unknown. The addition of these galaxies to existing extragalactic

Jason Pruet, George M. Fuller

We give a geometric interpretation of the neutrino 'oscillation length resonance' recently discovered by Petcov. We use this picture to identify two new solutions for oscillation length resonances in a 3-layer earth model.

Anne-Christine Davis, Matthew Lilley, Ola Tornkvist

We point out that the lower bound on the primordial magnetic field required to seed the galactic dynamo is significantly relaxed in an open universe or in a universe with a positive cosmological constant. It is shown that, for reasonable cosmological parameters, primordial seed fields of strength 10^{-30} Gauss or less at the time of galaxy formation could e

Mariano Mendez

I summarize the available RXTE data of the 4 low-mass X-ray binaries (LMXBs) and Atoll sources Aql X-1, 4U 1728-34, 4U 1608-52, and 4U 1636-53. I concentrate on the relation between the frequencies of the quasi-periodic oscillations at kilohertz frequencies (kHz QPOs) and the X-ray flux and colors of these sources. In these 4 sources the kHz QPOs are only ob

Graham D. Kribs, Adam K. Leibovich, I. Z. Rothstein

Recent numerical evidence suggests that a mass spectrum of primordial black holes (PBHs) is produced as a consequence of near critical gravitational collapse. Assuming that these holes formed from the initial density perturbations seeded by inflation, we calculate model independent upper bounds on the mass variance at the reheating temperature by requiring t

Lubos Motl, Tom Banks

We study the asymptotic limits of the heterotic string theories compactified on tori. We find a bilinear form uniquely determined by dualities which becomes Lorentzian in the case of one spacetime dimension. For the case of the SO(32) theory, the limiting descriptions include SO(32) heterotic strings, type I, type IA and other T-duals, M-theory on K3, type I

Fotini Markopoulou

Quantum causal histories are defined to be causal sets with Hilbert spaces attached to each event and local unitary evolution operators. The reflexivity, antisymmetry, and transitivity properties of a causal set are preserved in the quantum history as conditions on the evolution operators. A quantum causal history in which transitivity holds can be treated a

George B. Martins, Robert Eder, Elbio Dagotto

The 2D extended $\rm t-J$ model is studied computationally in a broad region of parameter space, motivated by recent photoemission experiments for the undoped cuprate $\rm Ca_2 Cu O_2 Cl_2$ (F. Ronning et al., Science {\bf 282}, 2067 (1998)). The one-hole ground state is shown to develop robust antiferromagnetic (AF) correlations between spins separated by t

Gia Dvali, Alexei Yu. Smirnov

We study implications of theories with sub-millimeter extra dimensions and $M_f \sim (1 - 10) $ TeV scale quantum gravity for neutrino physics. In these theories, the left-handed neutrinos as well as other standard model (SM) particles, are localized on a brane embedded in the bulk of large extra space. Mixing of neutrinos with (SM) singlet fermions propagat

S. F. King

We argue that in order to provide a natural explanation of both neutrino mass hierarchies and large neutrino mixing angles, as required by the atmospheric neutrino data, a single right-handed neutrino must give the dominant contribution to the 23 block of the light effective neutrino matrix, and illustrate this mechanism in the framework of models with U(1)

David P. DiVincenzo, Barbara M. Terhal, Ashish V. Thapliyal

Two families of bipartite mixed quantum states are studied for which it is proved that the number of members in the optimal-decomposition ensemble --- the ensemble realizing the entanglement of formation --- is greater than the rank of the mixed state. We find examples for which the number of states in this optimal ensemble can be larger than the rank by an

Simon Capstick, T. -S. H. Lee, W. Roberts, A. Svarc

It is pointed out that the third of five low-lying P11 states predicted by a constituent quark model can be identified with the third of four states in a solution from a three-channel analysis by the Zagreb group. This is one of the so-called ``missing'' resonances, predicted at 1880 MeV. The fit of the Zagreb group to the pi N -> eta N data is the c

Antonio L. Maroto, Anupam Mazumdar

We study the production of spin 3/2 particles in homogeneous scalar and gravitational backgrounds from the mode-mixing Bogolyubov method. Considering only helicity $\pm 3/2$ states we can reduce the problem to a standard Dirac fermion calculation and apply the standard techniques in a straightforward way. As an example we consider a supergravity inflationary

R. B. C. Henry, Guy Worthey

This review recaps significant results as they apply to non-dwarf galaxies, including the Milky Way, spiral disks and bulges, and elliptical and lenticular galaxies. Conclusions that span the galaxy types treated here are as follows. All galaxies, on average, have heavy element abundances (metallicities) that systematically decrease outward from their galact

Gabriel Lopes Cardoso, Bernard de Wit, Thomas Mohaupt

We review modifications of the Bekenstein-Hawking area law for black hole entropy in the presence of higher-derivative interactions. In four-dimensional N=2 compactifications of string theory or M-theory these modifications are crucial for finding agreement between the macroscopic entropy obtained from supergravity and the microscopic entropy obtained by cou

A. T. Suzuki, A. G. M. Schmidt

Feynman integrals in the physical light-cone gauge are harder to solve than their covariant counterparts. The difficulty is associated with the presence of unphysical singularities due to the inherent residual gauge freedom in the intermediate boson propagators constrained within this gauge choice. In order to circumvent these non-physical singularities, the

Claude Bouchiat, Marc Mezard

We study the elastic behaviour of a supercoiled DNA molecule. The simplest model is that of a rod like chain, involving two elastic constants, the bending and the twist rigidities. We show that this model is singular and needs a small distance cut-off, which is a natural length scale giving the limit of validity of the model, of the order of the double helix

Jiliang Jing, Mu-Lin Yan

By using the 't Hooft "brick wall" model and the Pauli-Villars regularization scheme we calculate the statistical-mechanical entropy arising from the minimally coupled scalar fields which rotate with the azimuthal angular velocity $Ω_0=Ω_H$ ($Ω_H$ is the angular velocity of the black hole horizon) in the general four-dimensional non-extreme stati

K. Miyagawa, H. Yamamura

We search $t$-matrix poles for $ΛN-ΣN$ coupling interactions using two soft core models of the Nijmegen group which bind the hypertriton at the correct binding energy, and hard core models which are still influential in hypernuclear physics. To treat the hard core potentials, a useful method for calculating the off-shell $t$-matrix is proposed. We find poles

M. Anselmino, M. Bertini, F. Caruso, F. Murgia

Final state quark-antiquark interactions give origin to non zero values of the off-diagonal element rho_{1,-1} of the helicity density matrix of vector mesons produced in e+e- annihilations, as confirmed by recent OPAL data on Phi, D^* and K^*'s. New predictions are given for rho_{1,-1} of several mesons produced at large x_E and small p_T -- i.e. collinear

Tero T. Heikkila, Martti M. Salomaa, C. J. Lambert

We examine universal conductance fluctuations (UCFs) in mesoscopic normal-superconducting-normal (N-S-N) structures using a numerical solution of the Bogoliubov - de Gennes equation. We discuss two cases depending on the presence (``open'' structure) or absence (``closed'' structure) of quasiparticle transmission. In contrast to N-S structure

Qingshan Yuan, Peter Thalmeier

Based on a two-dimensional extended Hubbard model with electron-phonon interaction, we have studied the effect of polaron formation on the charge ordering (CO) transition. It is found that for fully ferromagnetically ordered spins the CO state may go through a process of appearance, collapse and reappearance with decreasing temperature. This is entirely due

Samuel L. Braunstein

We show that squeezing is an irreducible resource which remains invariant under transformations by linear optical elements. In particular, we give a decomposition of any optical circuit with linear input-output relations into a linear multiport interferometer followed by a unique set of single mode squeezers and then another multiport interferometer. Using t

A. B. Kobakhidze

The minimal dynamical electroweak symmetry breaking through top condensation in the presence of compact large extra dimensions is studed. It is shown that thanks to the power-low evolution of gauge and Yukawa couplings the original BHL predictions for the top quark mass are significantly lowered and even for small cut-off scale $Λ\sim few$ TeV one can obtain

M. Henneaux, B. Julia, S. Silva

Straightforward application of the standard Noether method in supergravity theories yields an incorrect superpotential for local supersymmetry transformations, which gives only half of the correct supercharge. We show how to derive the correct superpotential through Lagrangian methods, by applying a criterion proposed recently by one of us. We verify the equ

H. Ritter

We derive a simple analytical solution for the evolution of a close binary with nuclear time-scale driven mass transfer from a giant. This solution is based on the well-known fact that the luminosity and the radius of a giant scale to a good approximation as simple power laws of the mass M_c of the degenerate helium core. Comparison with results of numerical

Oliver Haschke, Werner Ruehl

Trigonometric invariants are defined for each Weyl group orbit on the root lattice. They are real and periodic on the coroot lattice. Their polynomial algebra is spanned by a basis which is calculated by means of an algorithm. The invariants of the basis can be used as coordinates in any cell of the coroot space and lead to an exactly solvable model of Suthe

Holger Schanz, Uzy Smilansky

We consider the Schroedinger operator on graphs and study the spectral statistics of a unitary operator which represents the quantum evolution, or a quantum map on the graph. This operator is the quantum analogue of the classical evolution operator of the corresponding classical dynamics on the same graph. We derive a trace formula, which expresses the spect

Gustav W. Delius, Georg M. Gandenberger

We determine the exact quantum particle reflection amplitudes for all known vacua of a_n^(1) affine Toda theories on the half-line with integrable boundary conditions. (Real non-singular vacuum solutions are known for about half of all the classically integrable boundary conditions.) To be able to do this we use the fact that the particles can be identified

Peter Kramer

In the window approach to quasicrystals, the atomic position space E_parallel is embedded into a space E^n = E_parallel + E_perp. Windows are attached to points of a lattice Lambda \in E^n. For standard 5fold and icosahedral tiling models, the windows are perpendicular projections of dual Voronoi and Delone cells from Lambda. Their cuts by the position space

Karyn Le Hur

We present an Ising-like intermediate phase for one-dimensional Kondo insulator systems. Resulting from a spinon splitting, its low-energy excitations are critical Ising modes, whereas the triplet sector has a spectral gap. It should occur as long as the RKKY oscillation amplitude dominates over any direct exchange between localized spins. The chiral fixed p

Ross H. McKenzie, Perez Moses

The frequency dependence of the interlayer conductivity of a layered Fermi liquid in a magnetic field which is tilted away from the normal to the layers is considered. For both quasi-one- and quasi-two-dimensional systems resonances occur when the frequency is a harmonic of the frequency at which the magnetic field causes the electrons to oscillate on the Fe

M. Pospelov, A. Ritz

We demonstrate that the QCD sum rule method can be successfully applied to the calculation of CP-odd electromagnetic observables induced by a vacuum theta--angle. We implement the approach in calculating the electric dipole moment of the rho meson to ~30% precision, and find that the result can also be explicitly related to the vacuum topological susceptibil

C. Adami, N. J. Cerf

We suggest that the framework of quantum information theory, which has been developing rapidly in recent years due to intense activity in quantum computation and quantum communication, is a reasonable starting point to study non-equilibrium quantum statistical phenomena. As an application, we discuss the non-equilibrium quantum thermodynamics of black hole f

Jos Uffink, Jan Hilgevoord

Quantitative measures are introduced for the indistinguishability $U$ of two quantum states in a given measurement and the amount of interference $I$ observable in this measurement. It is shown that these measures obey an inequality $U\geq I$ which can be seen as an exact formulation of Bohr's claim that one cannot distinguish between two possible paths

Matthew J. Donald

In a series of papers, a many-minds interpretation of quantum theory has been developed. The aim in these papers is to present an explicit mathematical formalism which constitutes a complete theory compatible with relativistic quantum field theory. In this paper, which could also serve as an introduction to the earlier papers, three issues are discussed. Fir

Geert Jan van Oldenborgh

There has been intense debate about the causes of the 1997-1998 El Nino. One side sees the obvious intense westerly wind events as the main cause for the exceptional heating in summer 1997, the other emphasizes slower oceanic processes. We present a quantitative analysis of all factors contributing to the onset of this El Nino. At six months' lead time t

A. Kruger, W. Glockle

We start from a Lagrangian describing scalar "nucleons" and mesons which interact through a simple vertex. Okubo's method of unitary transformation is used to describe a single nucleon dressed by its meson cloud. We find an expression for the physical mass of the nucleon being correct up to second order in the coupling constant. It is then verifi

Boris Krippa, Michael C. Birse

In response to Kim's comment (nucl-th/9903040) on the sum rules for pion-baryon coupling constants obtained in hep-ph/9512259 and hep-ph/9606471, we point out that our treatment of the continuum is consistent with duality and with the fact that the correlator in the presence of an external meson or field should be represented by a double dispersion relat

Yongkyu Ko, Myung Ki Cheoun, Il-Tong Cheon

The deuteron binding energy extracted from the reaction ${}^1H(n,γ){}^2H$ is reviewed with the exact relativistic formula, where the initial kinetic energy and the Doppler effect are taken into account. We find that the negligible initial kinetic energy of the neutron could cause a significant uncertainty which is beyond the errors available up to now. There

Andreas G. Piepke, S. Wayne Moser, Vladimir M. Novikov

We report on the development and deployment of 11.3 tons of 0.1% Gd loaded liquid scintillator used in the Palo Verde reactor neutrino oscillation experiment. We discuss the chemical composition, properties, and stability of the scintillator elaborating on the details of the scintillator preparation crucial for obtaining a good scintillator quality and stabi

A. Garcia, E. G. Adelberger, C. Ortiz, H. E. Swanson

The positron-neutrino correlation in the 0^+ \to 0^+ βdecay of ^{32}Ar was measured at ISOLDE by analyzing the effect of lepton recoil on the shape of the narrow proton group following the superallowed decay. Our result is consistent with the Standard Model prediction; for vanishing Fierz interference we find a=0.9989 \pm 0.0052 \pm 0.0036. Our result leads

Denis Blackmore, Roman Samulyak, Anthony Rosato

A new class of integro-partial differential equation models is derived for the prediction of granular flow dynamics. These models are obtained using a novel limiting averaging method (inspired by techniques employed in the derivation of infinite-dimensional dynamical systems models) on the Newtonian equations of motion of a many-particle system incorporating

Andrey N. Leznov

Exactly integrable systems connected to semisimple algebras of second rank with an arbitrary choice of grading are presented in explicit form. General solutions of these systems are expressed in terms of matrix elements of two fundamental representations of the corresponding semisimple groups.

Nicolaas P. Landsman

We attempt to reconstruct the irreducible unitary representations of the Banach Lie group $U_0(\H)$ of all unitary operators $U$ on a separable Hilbert space $\H$ for which $U-{\mathbb I}$ is compact, originally found by Kirillov and Ol'shanskii, through constrained quantization of its coadjoint orbits. For this purpose the coadjoint orbits are realized

Alexander Shapovalov, A. Yu. Trifonov

A concept of semiclassically concentrated solutions is formulated for the multidimensional nonlinear Schrödinger equation (NLSE) with an external field. These solutions are considered as multidimensional solitary waves. The center of mass of such a solution is shown to move along with the bicharacteristics of the basic symbol of the corresponding linear Schr

R. Radha, S. Vijayalakshmi, Muthusamy Lakshmanan

In this letter, we report the existence of a novel type of explode-decay dromions, which are exponentially localized coherent structures whose amplitude varies with time, through Hirota method for a nonisospectral Davey-Stewartson equation I discussed recently by Jiang. Using suitable transformations, we also point out such solutions also exist for the isosp

Boris A. Kupershmidt

The multiplication in the Virasoro algebra \[ [e_p, e_q] = (p - q) e_{p+q} + θ\left(p^3 - p\right) δ_{p + q}, \qquad p, q \in {\mathbf Z}, \] \[ [θ, e_p] = 0, \] comes from the commutator $[e_p, e_q] = e_p * e_q - e_q * e_p$ in a quasiassociative algebra with the multiplication \renewcommand{\theequation}{$*$} \be \ba{l} \ds e_p * e_q = - {q (1 + εq) \over 1

S. Melkonian

The cubic Hénon-Heiles system contains parameters, for most values of which, the system is not integrable. In such parameter regimes, the general solution is expressible in formal expansions about arbitrary movable branch points, the so-called psi-series expansions. In this paper, the convergence of known, as well as new, psi-series solutions on real time in

Gentiana Danila

We compute the cohomology spaces for the tautological bundle tensor the determinant bundle on the punctual Hilbert scheme H of subschemes of length n of a smooth projective surface X. We show that for L and A invertible vector bundles on X, and w the canonical bundle of X, if $w^{-1}\otimes L$, $w^{-1}\otimes A$ and A are ample vector bundles, then the highe

Gentiana Danila

We provide supporting examples to Le Potier's Strange duality conjecture, in the case of the moduli space M of rank 2 semi-stable sheaves on the projective plane, with even first Chern class, and second Chern class less or equal to 19. We compute in this case the dimension of the space of global sections of the determinant bundle on M.

Evgenij V. Troitsky

We prove the index theorem for elliptic operators acting on sections of bundles where fiber is equal to a projective module over a C*-algebra, in the situation of action of a compact Lie group on this algebra as well as on the total space commuting with symbol. As an application the equivariant index theorem for families over the direct product of base by th

Scott Pauls

In this paper, we prove results concerning the large scale geometry of connected, simply connected nonabelian nilpotent Lie groups equipped with left invariant Riemannian metrics. Precisely, we prove that there do not exist quasi-isometric embeddings of such a nilpotent Lie group into either a CAT(0) metric space or an Alexandrov metric space with curvature

Alejandro Cabo, Alexis Amezaga

The possibility that the expansion rate of the Universe, as reflected by the Red Shift, could be produced by the existence of the dilaton field is explored. The analysis starts from previously studied solutions of the Einstein equations for gravity interacting with a massive scalar field. It is firstly underlined that such solutions can produce the observed

Michael B. Green

Paper withdrawn. The argument was based on a misconception

R. C. Hwa, Y. Wu

The critical behaviors of quark-hadron phase transition are explored by use of the Ising model adapted for hadron production. Various measures involving the fluctuations of the produced hadrons in bins of various sizes are examined with the aim of quantifying the clustering properties that are universal features of all critical phenomena. Some of the measure

Mario Everaldo de Souza

Many evidences for the existence of the superstrong interaction are presented and many predictions are made. The light antiquark flavor asymmetry is calculated and shown to agree with experimental data. The formation of galaxies is explained and their size and mass are calculated. Contents: 1) Preliminary Ideas on Prequarks and the Number of Quarks; 2) Distr

G. Moortgat-Pick, H. Fraas

Production and decay of gaugino-like charginos are crucially determined by sneutrino exchange. Therefore we study the pair production of charginos e^+ e^- -> chi^+_1 chi^-_1 with polarized beams and the subsequent decay chi^-_1 -> chi^0_1 e^- nu_e, including the complete spin correlations between production and decay. The spin correlations have strong influe

Tatsu Takeuchi, Will Loinaz, Aaron K. Grant

We review the current status of precision electroweak measurements and the constraints they impose on new physics. We perform a model independent analysis using the STU-formalism of Ref. 1, and then discuss how the Z-pole data from LEP and SLD can be used to constrain models that are not covered within that framework.

B. Ziaja

The improved method of intermittent data analysis is proposed. It exploits, in addition to the standard density moments, the information on the bin-bin correlations, observed in the data and expressed in terms of the density correlators. The improving recovering corrections are implemented into the data analysis in the form of the recursive algorithm, and te

R. Fiore, L. L. Jenkovszky, V. K. Magas, F. Paccanoni

The scattering amplitude in the dual model with Mandelstam analyticity and trajectory $α(s)=α_{0}-γ\ln [ (1+β\sqrt{s_{0} -s})/(1+ β\sqrt{s_{0}})]$ is studied in the limit $s,|t|\to \infty, s/t=const.$ By using the saddle point method, a series decomposition for the scattering amplitude is obtained, with the leading and two sub-leading terms calculated explic

Tatsuo Kobayashi, Jisuke Kubo, Hitoshi Shimabukuro

We study soft SUSY breaking parameters in M-theory with and without 5-brane moduli fields. We investigate successful electroweak symmetry breaking and the positivity of stau mass squared. We study mass spectra in allowed regions.

P. Vogel, J. F. Beacom

The reaction $\barν_e + p \to e^+ + n$ is very important for low-energy ($E_ν\lesssim 60$ MeV) antineutrino experiments. In this paper we calculate the positron angular distribution, which at low energies is slightly backward. We show that weak magnetism and recoil corrections have a large effect on the angular distribution, making it isotropic at about 15 M

David Atwood, Shaouly Bar-Shalom, Amarjit Soni

We consider the production of gravitons via two photon fusion in Kaluza-Klein theories which allow TeV scale gravitational interactions. We find that the processes l+ l- to l+ l- + graviton, with l=electron or muon can put quite stringent bounds on such theories. For example, with two extra dimensions at the Next Linear Collider with a center of mass energy

C. P. Burgess

These lectures are an extremely condensed version of the theory of Goldstone bosons, with general features illustrated using a simple model. A more comprehensive version of these lectures, which includes a general discussion of effective theories of Goldstone bosons, including applications to the low-energy behaviour of pions, spin waves (in antiferromagnets

I. L. Bogolubsky, V. K. Mitrjushkin, M. Müller-Preussker, P. Peter

The Gribov ambiguity problem is studied for compact U(1) lattice theory within the Lorentz gauge. In the Coulomb phase, it is shown that apart from double Dirac sheets all gauge (i.e. Gribov) copies originate mainly from the zero-momentum modes of the gauge fields. The removal of the zero-momentum modes turns out to be necessary for reaching the absolute max

S. P. Riley, Z. D. Greenwood, W. R. Kropp, L. R. Price

Cross sections for the disintegration of the deuteron via neutral-current (NCD) and charged-current (CCD) interactions with reactor antineutrinos are measured to be 6.08 +/- 0.77 x 10^(-45) cm-sq and 9.83 +/- 2.04 x 10^(-45) cm-sq per neutrino, respectively, in excellent agreement with current calculations. Since the experimental NCD value depends upon the C

S. V. Babak, L. P. Grishchuk

The field theoretical description of the general relativity (GR) is further developed. The action for the gravitational field and its sources is given explicitely. The equations of motion and the energy-momentum tensor for the gravitational field are derived by applying the variational principle. We have succeeded in constructing the unique gravitational ene

Bruce Edmonds

Paper journals use a small number of trusted academics to select information on behalf of all their readers. This inflexibility in the selection was justified due to the expense of publishing. The advent of cheap distribution via the internet allows a new trade-off between time and expense and the flexibility of the selection process. This paper explores one

A. J. Wagner, J. M. Yeomans

We use lattice Boltzmann simulations to study the effect of shear on the phase ordering of a two-dimensional binary fluid. The shear is imposed by generalising the lattice Boltzmann algorithm to include Lees-Edwards boundary conditions. We show how the interplay between the ordering effects of the spinodal decomposition and the disordering tendencies of the

O. Zobay, E. V. Goldstein, P. Meystre

We study the conditions under which atomic condensates can be used as a recording media and then suggest a reading scheme which allows to reconstruct an object with atomic reading beam. We show that good recording can be achieved for flat condensate profiles and for negative detunings between atomic Bohr frequency and optical field frequency. The resolution

J. Kim, F. Kirchhoff, W. G. Aulbur, J. W. Wilkins

We propose a di-interstitial model for the P6 center commonly observed in ion implanted silicon. The di-interstitial structure and transition paths between different defect orientations can explain the thermally activated transition of the P6 center from low-temperature C1h to room-temperature D2d symmetry. The activation energy for the defect reorientation

A. J. Wagner, L. Giraud, C. E. Scott

We developed a new lattice Boltzmann method that allows the simulation of two-phase flow of viscoelastic liquid mixtures. We used this new method to simulate a bubble rising in a viscoelastic fluid and were able to reproduce the experimentally observed cusp at the trailing end of the bubble.

K Huang

We calculate the transition temperature of a uniform dilute Bose gas with repulsive interactions, using a known virial expansion of the equation of state. We find that the transition temperature is higher than that of an ideal gas, with a fractional increase K_0(na^3)^{1/6}, where n is the density and a is the S-wave scattering length, and K_0 is a constant

H. Srikanth, J. Wiggins, H. Rees

A resonant method based on a tunnel-diode oscillator (TDO) for precision measurements of relative impedance changes in materials, is described. The system consists of an effective self-resonant LC-tank circuit driven by a forward-biased tunnel diode operating in its negative resistance region. Samples under investigation are placed in the core of an inductiv

S. Henneberger, E. Frey, P. G. Maier, F. Schwabl

We study the critical dynamics of three-dimensional ferromagnets with uniaxial anisotropy by taking into account exchange and dipole-dipole interaction. The dynamic spin correlation functions and the transport coefficients are calculated within a mode coupling theory. It is found that the crossover scenario is determined by the subtle interplay between three

R. Badrinarayanan, A. Góngora-T, Jorge V. José

We present results of a detailed quantum mechanical study of a gas of $N$ noninteracting electrons confined to a circular boundary and subject to homogeneous dc plus ac magnetic fields $(B=B_{dc}+B_{ac}f(t)$, with $f(t+2π/ω_0)=f(t)$). We earlier found a one-particle {\it classical} phase diagram of the (scaled) Larmor frequency $\tildeω_c=omega_c/ω_0$ {\rm v

R. S. Mendes, I. T. Pedron

A family of nonlinear ordinary differential equations with arbitrary order is obtained by using nonextensive concepts related to the Tsallis entropy. Applications of these equations are given here. In particular, a connection between Tsallis entropy and the one-dimensional correlated anomalous diffusion equation is established. It is also developed explicitl

Ignacio G. Cuesta, Indubala I. Satija

Fibonacci system with both diagonal and off-diagonal disorder is mapped to a model with dimer type 'defects'. The model exhibit resonance transition corresponding to zero reflectance condition resulting in extended states in the system. These Bloch-type states reside on the line of inversion symetry of the energy spectrum and include states at the ba

S. V. Lotkhov, H. Zangerle, A. B. Zorin, J. Niemeyer

We report on the operation of a single electron trap comprising a chain of four Al/AlOx/Al tunnel junctions attached, at one side, to a memory island and, at the other side, to a miniature on-chip Cr resistor R=50 kOhm which served to suppress cotunneling. At appropriate voltage bias the bi-stable states of the trap, with the charges differing by the element

Ch. Gruber, L. Frachebourg

The time evolution of the adiabatic piston problem and the consequences of its stochastic motion are investigated. The model is a one dimensional piston of mass $M$ separating two ideal fluids made of point particles with mass $m\ll M$. For infinite systems it is shown that the piston evolves very rapidly toward a stationary nonequilibrium state with non zer

D. Lynden-Bell, R. M. Lynden-Bell

The wave functions of Boson and Fermion gases are known even when the particles have harmonic interactions. Here we generalise these results by solving exactly the N-body Schrodinger equation for potentials V that can be any function of the sum of the squares of the distances of the particles from one another in 3 dimensions. For the harmonic case that funct

F. Evers

An effective Hamiltonian for spinless electrons in the lowest Landau level (LLL) close to half filling is derived. As opposed to the treatment in standard Chern-Simons theories (CS) we first project to the LLL and only then apply a CS-transformation on the Hamiltonian. The transformed field operators act in the lowest Landau level only {\it and} have fermion

Kazuo Ueda, Shin Miyahara

Extensions of the Shastry-Sutherland model are possible in various ways. In particular, it is possible to construct a natural model in three dimensions which has the exact dimer ground state. Recently found spin gap system SrCu_2(BO_3)_2 has this structure. The exchange constants between the layers is expected to be smaller than the intra-layer couplings. Ho

V. V. Flambaum, V. V. Sokolov

A conducting 1D chain or 2D film inside (or on the surface of) an insulator is considered. Impurities displace the charges inside the insulator. This results in a long-range fluctuating electric field acting on the conducting line (plane). This field can be modeled by that of randomly distributed electric dipoles. This model provides a random correlated pote

Yu. E. Kuzovlev

The equations of viscous evolution of 3D arbitrarily shaped vortices in an isotropic type II superconductor and necessary boundary conditions are formulated in the frame of London approximation. The theory is applied to analyse characteristic scenaria of vortex penetration into current-carrying thick plate or bulk samples with another geometry. It is shown t

N. P. Rapapa, A. J. Bray

Corrections to scaling, associated with deviations of the order parameter from the scaling morphology in the initial state, are studied for systems with O(n) symmetry at zero temperature in phase-ordering kinetics. Including corrections to scaling, the equal-time pair correlation function has the form C(r,t) = f_0(r/L) + L^{-omega} f_1(r/L) + ..., where L is

Randall D. Kamien, Alex J. Levine

Boundary effects in liquid-crystalline phases can be large due to long-ranged orientational correlations. We show that the chiral hexatic phase can be locked into an apparent three-dimensional N+6 phase via such effects. Simple numerical estimates suggest that the recently discovered "polymer hexatic" may actually be this locked phase.

Parongama Sen

The probability distributions of the masses of the clusters spanning from top to bottom of a percolating lattice at the percolation threshold are obtained in all dimensions from two to five. The first two cumulants and the exponents for the universal scaling functions are shown to have simple power law variations with the dimensionality. The cases where mult

Chin-Kun Hu, N. Sh. Izmailian, K. B. Oganesyan

Using an iteration technique, we obtain exact expressions for the free energy and the magnetization of an Ising model on a two - layer Bethe lattice with intralayer coupling constants J1 and J2 for the first and the second layer, respectively, and interlayer coupling constant J3 between the two layers; the Ising spins also couple with external magnetic field

J. L. Martin, C. R. McKenzie, N. R. Thomas, J. C. Sharpe

Two distinct mechanisms are investigated for transferring a pure 87Rb Bose-Einstein condensate in the F = 2, mF = 2 state into a mixture of condensates in all the mF states within the F = 2 manifold. Some of these condensates remain trapped whilst others are output coupled in the form of an elementary pulsed atom laser. Here we present details of the condens

J. Matsuno, A. Fujimori, L. F. Mattheiss

The band structure of the cubic spinel compound LiV_2O_4, which has been reported recently to show heavy Fermion behavior, has been calculated within the local-density approximation using a full-potential version of the linear augmented-plane-wave method. The results show that partially-filled V 3d bands are located about 1.9 eV above the O 2p bands and the

Y. Nakamura, Yu. A. Pashkin, J. S. Tsai

A small superconducting electrode (a single-Cooper-pair box) connected to a reservoir via a Josephson junction constitutes an artificial two-level system, in which two charge states that differ by 2e are coupled by tunneling of Cooper pairs. Despite its macroscopic nature involving a large number of electrons, the two-level system shows coherent superpositio

Kevin C. Hewitt, N. L. Wang, J. C. Irwin, D. M. Pooke

Raman scattering studies have been performed on underdoped Bi2Sr2CaCu2O8+delta. In single crystals underdoped by oxygen removal, a 590 cm-1 peak is observed in the B1g spectrum. The feature is observed to soften in frequency by 3.8% with isotopic exchange for 16-O by 18-O. In contrast, the 590cm-1 peak is not observed in crystals underdoped by Y substitution

A. B. Shick

We performed first - principles relativistic full-potential linearized augmented plane wave calculations for strained tetragonal ferromagnetic La(Ba)MnO$_3$ with an assumed experimental structure of thin strained tetragonal La$_{0.67}$Ca$_{0.33}$MnO$_3$ (LCMO) films grown on SrTiO$_3$[001] and LaAlO$_3$[001] substrates. The calculated uniaxial magnetic aniso

R. Carretero-González, D. K. Arrowsmith, F. Vivaldi

Multistable coupled map lattices typically support travelling fronts, separating two adjacent stable phases. We show how the existence of an invariant function describing the front profile, allows a reduction of the infinitely-dimensional dynamics to a one-dimensional circle homeomorphism, whose rotation number gives the propagation velocity. The mode-lockin