November 2000 arXiv papers

A. Majumder, C. Gale

We investigate the effects of a baryon-antibaryon asymmetry on the spectrum of dileptons radiating from a quark gluon plasma. We demonstrate the existence of a new set of processes in this regime. The dilepton production rate from the corresponding diagrams is shown to be as important as that obtained from the usual quark-antiquark annihilation.

Charis Anastopoulos

We give a short, critical review of the issue of decoherence. We establish the most general framework in which decoherence can be discussed, how it can be quantified and how it can be measured. We focus on environment induced decoherence and its degree of usefulness for the interpretation of quantum theory. We finally discuss the emergence of a classical wor

C. S. Snow, S. L. Cooper, D. P. Young, Z. Fisk

We present inelastic light scattering measurements of EuO and Eu$_{1-x}$La$_{x}$B$_6$ ($x$=0, 0.005, 0.01, 0.03, and 0.05) as functions of doping, B isotope, magnetic field, and temperature. Our results reveal a variety of distinct regimes as a function of decreasing T: (a) a paramagnetic semimetal regime, which is characterized by a collision-dominated elec

Sadhan K. Adhikari

We study the collapse in a coupled Bose-Einstein condensate of two types of bosons 1 and 2 under the action of a trap using the time-dependent Gross-Pitaevskii equation. The system may undergo collapse when one, two or three of the scattering lengths $a_{ij}$ for scattering of boson $i$ with $j$, $i,j = 1, 2 $, are negative representing an attractive interac

Prot Pakonski, Karol Zyczkowski, Marek Kus

We study a certain class of classical one dimensional piecewise linear maps. For these systems we introduce an infinite family of Markov partitions into equal cells. The symbolic dynamics generated by these systems is described by bistochastic (doubly stochastic) matrices. We analyze the structure of graphs generated from the corresponding symbolic dynamics.

Mario Vietri, Gabriele Ghisellini, Davide Lazzati, Fabrizio Fiore

We consider models for the generation of the emission line recently discovered in the X-ray afterglow spectrum of several bursts, and especially of GRB 991216 observed by Chandra. These observations suggest the presence of 0.1-1 solar masses of iron in the vicinity of the bursts. We show that there are strong geometrical and kinematical constraints on the li

Donam Youm

We study the cosmological evolution of the closed universe on a spherical probe brane moving in the AdS$_m\times S^n$ background and the near-horizon background of the dilatonic D-branes. The Friedmann equations describing the evolution of the brane universe, and the effective energy density and pressure simulated on the probe brane due to its motion in the

J. Baacke, D. Cormier, H. J. de Vega, K. Heitmann

We consider an O(N) version of a massive, interacting, chiral supersymmetry model solved exactly in the large N limit. We demonstrate that the system approaches a stable attractor at high energy densities, corresponding to a non-perturbative state for which the relevant field quanta are massless. The state is one of spontaneously broken O(N), which, due to t

R. Casalbuoni, Z. Duan, F. Sannino

We construct the effective theories describing the electroweak interactions for the low energy excitations associated with the color superconductive phases of QCD at high matter density. The main result, for the 3 flavor case, is that the quasiparticle Goldstone boson $π^0$ decay into two physical massless photons is identical to the zero density case once w

J. P. Nicholson, K. J. Weston, D. Fowler

A Lagrangian column model has been developed to simulate the mean (monthly and annual) three-dimensional structure in ozone and nitrogen oxides concentrations in the boundary layer within and immediately around an urban area. Short time-scale photochemical processes of ozone, as well as emissions and deposition to the ground are simulated. The results show t

D. Bailin, G. V. Kraniotis, A. Love

Type IIB superstring models with the standard model gauge group on D3-branes and with massless matter associated with open strings joining D3-branes to D3-branes or D3-branes to ${\rm D}7_3$-branes are studied. Models with gauge coupling constant unification at an intermediate scale between about $10^{10}$ and $10^{12}$GeV and consistency with the observed v

C. Fuchs, Amand Faessler, E. Zabrodin, Yu-Ming Zheng

The dependence of $K^+$ production on the nuclear equation of state is investigated in heavy ion collisions. An increase of the excitation function of $K^+$ multiplicities obtained in heavy ($Au+Au$) over light ($C+C$) systems when going far below threshold which has been observed by the KaoS Collaboration strongly favours a soft equation of state. This obse

Harald Nieder, Yaron Oz

We construct dual supergravity descriptions of D3-branes wrapping associative 3-cycles $L$. We analyse the conditions for having five-dimensional background solutions of the form $AdS_2 \times L$ and show that they require $L$ to be of constant negative curvature type. This provides $AdS_2$ background solutions when $L$ is the hyperbolic space $H^3$ or its q

V. A. Khoze, A. D. Martin, M. G. Ryskin

We evaluate, in a model-independent way, the signal-to-background ratio for Higgs -> b bbar detection in exclusive double-diffractive events at the Tevatron and the LHC. For the missing-mass approach to be able to identify the Higgs boson, it will be necessary to use a central jet detector and to tag b quark jets. The signal is predicted to be very small at

Michael Gronau

Measuring phases in the Cabibbo-Kobayashi-Maskawa matrix through CP asymmetries in B decays is a major goal of current and future experiments. Methods based on charge-conjugation and isospin symmetries involve very little theoretical uncertainties, while schemes based on flavor SU(3) involve uncertainties due to SU(3) breaking. Resolving these uncertainties

L. Angelani, R. Di Leonardo, G. Parisi, G. Ruocco

We numerically investigate the aging dynamics of a monatomic Lennard-Jones glass, focusing on the topology of the potential energy landscape which, to this aim, has been partitioned in basins of attraction of stationary points (saddles and minima). The analysis of the stationary points visited during the aging dynamics shows the existence of two distinct reg

Vakif K. Onemli, Bayram Tekin

We study static vortex type solutions of pure gravity for $D \geq 4+1 $. Non-singular vortex solutions can be obtained by considering periodic Kaluza-Klein monopoles. We also show that away from the center of the vortices the space is described by the gravitational instantons derived from minimal surfaces.

Monika Randhawa, Manmohan Gupta

In the context of texture 4 - zero and texture 5 - zero hierarchical quark mass matrices, CP violating asymmetry in $B^o_d({\bar B}^o_d) \to ψK_S$ (sin2$β$) has been evaluated by considering quark masses at $m_Z$ scale. For a particular viable texture 4 - zero mass matrix the range of sin2βis: 0.27 - 0.60 and for the corresponding texture 5 - zero case it is

M. Koike, T. Ota, J. Sato

We study the sensitivity to the CP/T-violation search in the presence of ambiguities of the theoretical parameters. Three generations of neutrinos are considered. The parameters whose ambiguities are considered are the differences of the squared masses, the mixing angles, and the density of matter. We first consider the statistics that are sensitive to the g

David S. Berman, Vanicson L. Campos, Martin Cederwall, Ulf Gran

We examine noncommutative Yang-Mills and open string theories using magnetically and electrically deformed supergravity duals. The duals are near horizon regions of Dp-brane bound state solutions which are obtained by using O(p+1,p+1) transformations of Dp-branes. The action of the T-duality group implies that the noncommutativity parameter is constant along

GRAAL collaboration, F. Renard, M. Anghinolfi, O. Bartalini

The differential cross section for the reaction p(gamma, eta p) has been measured from threshold to 1100 MeV photon laboratory energy. For the first time, the region of the S11(1535) resonance is fully covered in a photoproduction experiment and allows a precise extraction of its parameters at the photon point. Above 1000 MeV, S-wave dominance vanishes while

I. Antoniadis, K. Benakli, A. Laugier

We compute the tree-level four-point scattering amplitudes in string models where matter fields live on D-brane intersections. Extracting the contribution of massless modes, we are left with dimension-six four-fermion operators which in general receive contributions from three different sources: exchange of massive Kaluza--Klein excitations, winding modes an

D. C. Brody, L. P. Hughston

Stochastic extensions of the Schrodinger equation have attracted attention recently as plausible models for state reduction in quantum mechanics. Here we formulate a general approach to stochastic Schrodinger dynamics in the case of a nonlinear state space of the type proposed by Kibble. We derive a number of new identities for observables in the nonlinear t

M. S. Marinov, E. Strahov

This article deals with non-adiabatic processes (i.e. processes excluded by the adiabatic theorem) from the geometrical (group-theoretical) point of view. An approximated formula for the probabilities of the non-adiabatic transitions is derived in the adiabatic regime for the case when the parameter-dependent Hamiltonian represents a smooth curve in the Lie

E. Strahov

The Lie group adiabatic evolution determined by a Lie algebra parameter dependent Hamiltonian is considered. It is demonstrated that in the case when the parameter space of the Hamiltonian is a homogeneous Kähler manifold its fundamental Kähler potentials completely determine Berry geometrical phase factor. Explicit expressions for Berry vector potentials (B

V. M. Chabanov, B. N. Zakhariev

Complex potential transformations which add imaginary parts to chosen energy levels are given and qualitatively explained. Unexpected shape similarity of potential perturbations for real and imaginary E-shifts of bound states are exhibited. The imaginary E-shifts in the continuous spectrum lead to a surprising quasi-periodic field raking up initial propagati

Lov K. Grover

This article introduces quantum computation by analogy with probabilistic computation. A basic description of the quantum search algorithm is given by representing the algorithm as a C program in a novel way.

M. A. Nielsen, J. Kempe

A remarkable feature of quantum entanglement is that an entangled state of two parties, Alice (A) and Bob (B), may be more disordered locally than globally. That is, S(A) > S(A,B), where S(.) is the von Neumann entropy. It is known that satisfaction of this inequality implies that a state is non-separable. In this paper we prove the stronger result that for

G. S. Agarwal, S. Dutta Gupta

We examine the feasibility of enhancing the fundamental radiative interactions between distant atoms. We present general arguments for producing enhancement. In particular, we show how giant dipole-dipole interaction can be produced by considering dipoles placed close to micron sized silica spheres. The giant interaction arises as the whispering gallery mode

J. G. Byatt-Smith

Nekrasov's integral equation describing water waves of permanent form, determines the angle phi that the wave surface makes with the horizontal. The independent variable s is a suitably scaled velocity potential, evaluated at the free surface, with the origin corresponding to the crest of the wave. For all waves, except for amplitudes near the maximum, p

D. Cinabro, K. Korbiak, R. Ehrlich, S. Henderson

Through the simultaneous measurement of the transverse size as a function of longitudinal position, and the longitudinal distribution of luminosity, we are able to measure the $β_y^\ast$ (vertical envelope function at the collision point), vertical emittance, and bunch length of colliding beams at the Cornell Electron-positron Storage Ring (CESR). This measu

Gerald L. Fitzpatrick

Starting with the premise that the electric charge associated with fundamental fermions (quarks and leptons) can, under certain circumstances, be appropriately represented as a real \emph{internal} 2-vector, the mathematical ``machinery'' implicit in the associated internal 2-space is shown to apply to \emph{all} fundamental fermions. In particular,

M. Del Estal, M. Centelles, X. Viñas, S. K. Patra

We extend the relativistic mean field theory model of Sugahara and Toki (TM1) by adding new couplings suggested by modern effective field theories. An improved set of parameters (TM1*) is developed with the goal to test the ability of the models based on effective field theory to describe the properties of finite nuclei and, at the same time, to be consisten

Aurel Bulgac

Some general features of the spectrum of the Hartree-Fock-Bogoliubov equations are examined. Special attention is paid to the asymptotic behavior of the single quasiparticle wave functions (s.qp.w.fs.), matter density distribution and density of the pair condensate. It is shown that due to the coupling between hole and particle states,the deeply bound hole s

S. K. Patra, M. Del Estal, M. Centelles, X. Viñas

Binding energies, quadrupole deformation parameters, spins and parities of the neutron-deficient odd $Z=N+1$ nuclei in the $A\sim 80$ region are calculated in the relativistic mean field approximation. The ground-state and low-lying configurations of the recently observed $^{77}$Y, $^{79}$Zr and $^{83}$Mo nuclei are analyzed. The calculated results are compa

Jiunn-Wei Chen, Xiangdong Ji

We study the possibility of measuring parity-violating pion-nucleon coupling h_{πNN}^{(1)} from π^+ electroproton production in the threshold region. We calculate the electron-helicity asymmetry in terms of h_{πNN}^{(1)} and the Z-boson exchange between the electron and proton in leading-order heavy-baryon chiral perturbation theory. From the result, we demo

M. Radici

Using the point-form approach to relativistic quantum mechanics, a covariant framework is presented for the calculation of proton and neutron electromagnetic form factors. Results for charge radii, magnetic moments, and electric as well as magnetic form factors are produced using the wave functions obtained in the so-called Goldstone-boson-exchange constitue

F. Herfurth, J. Dilling, A. Kellerbauer, G. Bollen

An ion beam cooler and buncher has been developed for the manipulation of radioactive ion beams. The gas-filled linear radiofrequency ion trap system is installed at the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. Its purpose is to accumulate the 60-keV continuous ISOLDE ion beam with high efficiency and to convert it into low-energy low-emittanc

T. A. Larsson

Let the DRO (Diffeomorphism, Reparametrization, Observer) algebra DRO(N) be the extension of $diff(N)\oplus diff(1)$ by its four inequivalent Virasoro-like cocycles. Here $diff(N)$ is the diffeomorphism algebra in $N$-dimensional spacetime and $diff(1)$ describes reparametrizations of trajectories in the space of tensor-valued $p$-jets. DRO(N) has a Fock mod

D. Borisov, P. Exner, R. Gadylshin, D. Krejcirik

We consider Dirichlet Laplacians on straight strips in R^2 or layers in R^3 with a weak local deformation. First we generalize a result of Bulla et al. to the three-dimensional situation showing that weakly coupled bound states exist if the volume change induced by the deformation is positive; we also derive the leading order of the weak-coupling asymptotics

Xiaoping Xu

Nongraded infinite-dimensional Lie algebras appeared naturally in the theory of Hamiltonian operators, the theory of vertex algebras and their multi-variable analogues. They play important roles in mathematical physics. This survey article is written based on the author's seminar talks on nongraded infinite-dimensional simple Lie algebras. The key constr

Bertfried Fauser, Zbigniew Oziewicz

A Clifford algebra Cl(V,η\in V^*\otimes V^*) jointly with a Clifford cogebra Cl(V,ξ\in V\otimes V) is said to be a Clifford biconvolution Cl(η,ξ). We show that a Clifford biconvolution for dim_R Cl=4 does possess an antipode iff det(id-ξ\circη)\neq 0. An antipodal Clifford biconvolution is said to be a Clifford Hopf gebra. We study the Clifford Hopf gebra an

Mircea Neagu

The paper constructs a generalized metrical multi-time Lagrange space, which allows a natural development of relativistic geometrical optics theories, in a general setting.

Robert P. C. de Marrais

G. Moreno's abstract depiction of the Sedenions' normed zero-divisors, as homomorphic to the exceptional Lie group G2, is fleshed out by exploring further structures the A-D-E approach of Lie algebraic taxonomy keeps hidden. A breakdown of table equivalence among the half a trillion multiplication schemes the Sedenions allow is found; the 168 element

Keiji Oguiso

We remark the density of the jumping loci of the Picard number of a hyperkähler manifold under small one-dimensional deformation and provide some applications for the Mordell-Weil groups of Jacobian K3 surfaces.

Hajime Tsuji

We prove the invariance of plurigenera under smooth projective deformations of varieties with nonnegative Kodaira dimensions.

D. Kaledin

A canonical hyperkaehler metric on the total space $T^*M$ of a cotangent bundle to a complex manifold $M$ has been constructed recently by the author (see alg-geom/9710026). This paper presents the results of alg-geom/9710026 in a streamlined and simplified form. The only new result is an explicit formula obtained for the case when $M$ is an Hermitian symmet

Hiroaki Terao, Anne V. Shepler

Let W be a finite group generated by unitary reflections and A be the set of reflecting hyperplanes. We will give a characterization of the logarithmic differential forms with poles along A in terms of anti-invariant differential forms. If W is a Coxeter group defined over the real numbers, then the characterization provides a new method to find a basis for

Stefan Blum

We show that diagonal subalgebras and generalized Veronese subrings of a bigraded Koszul algebra are Koszul. We give upper bounds for the regularity of sidediagonal and relative Veronese modules and apply the results to symmetric algebras and Rees rings.

Thomas Dent

We show that, in perturbative string models where the source of CP violation is a complex vacuum expectation value (v.e.v.) for one or more compactification moduli, CP is conserved if a CP transformation acting on the modulus values is an element of a target-space (self-)duality group. Where the duality group is SL(2,Z) the result confirms a conjecture of Ba

H. R. Christiansen, O. M. Del Cima, M. M. Ferreira, J. A. Helayel-Neto

In this talk, we present a parity-preserving QED3 model with spontaneous breaking of a local U(1)-symmetry. The breaking is accomplished by a potential of the phi^6-type. It is shown that a net attractive interaction appears in the Moeller scattering (s- and p-wave scatterings between two electrons) as mediated by the gauge field and a Higgs scalar. We show,

S. Korden

We consider a system of D5/D1 branes in the supergravity background AdS_3xS^3xX, where X is T^4 or K3. By investigating the structure of the missing states in the conformal description, we are able to extend the AdS/CFT correspondence to W algebras. As a test of this new formulation the results are compared to Hilbert schemes and more general supergravity ba

Spenta R. Wadia

We briefly review the microscopic modeling of black holes as bound states of branes in the context of the soluble D1-D5 system. We present a discussion of the low energy brane dynamics and account for black hole thermodynamics and Hawking radiation rates. These considerations are valid in the regime of supergravity due to the non-renormalization of the low e

Laurent Houart, Yolanda Lozano

We discuss various aspects of the description of branes as topological solitons in unstable brane systems of higher dimensions. We first describe a classification of all the possible realisations of branes of M and type II theories as topological solitons of a brane-antibrane system. We then present a description of type IIB NS-NS p-branes in terms of topolo

Parthasarathi Majumdar

The issue of black hole entropy is reexamined within a finite lattice framework along the lines of Wheeler, 't Hooft and Susskind, with an additional criterion to identify physical horizon states contributing to the entropy. As a consequence, the degeneracy of physical states is lower than that attributed normally to black holes. This results in correcti

Per Sundell

We construct Spin(p+1,p+1) covariant Dp-brane bound states by using that the potentials in the RR sector of toroidically compactified type II supergravity transform as a chiral spinor of the T-duality group. As an application, we show the invariance of the zero-force condition for a probe D-brane under noncommutative deformations of the background, which giv

A. Marshakov

We consider the Seiberg-Witten Toda chains arising in the context of exact solutions to N=2 SUSY Yang-Mills and their relation to the properties of N=1 SUSY gauge theories. In particular, we discuss their "perturbative" and "solitonic" degenerations and demonstrate some relations of the latter ones to the confining properties of N=1 vacua.

Florian Girelli

Left-right symmetric models are analyzed in the context of noncommutative geometry where we show that spontaneous parity violation is ruled out.

Lincoln Wolfenstein

Three possibilities for the origin of CP violation are discussed: (1) the Standard Model in which all CP violation is due to one parameter in the CKM matrix, (2) the superweak model in which all CP violation is due to new physics and (3) the Standard Model plus new physics. A major goal of B physics is to distinguish these possibilities. CP violation implies

Aurora Perez Martinez, Hugo Perez Rojas, Herman J. Mosquera Cuesta

A degenerate neutron gas in equilibrium with a background of electrons and protons in a magnetic field exerts its pressure anisotropically, having a smaller value perpendicular than along the magnetic field. For critical fields the magnetic pressure may produce the vanishing of the equatorial pressure of the neutron gas, and the outcome could be a transverse

John Ellis

Various developing topics in CP violation are reviewed. There are many theoretical reasons to hope that the CKM paradigm may be incomplete. It is surely too soon to be claiming new physics in ε^\prime/εor in D^0-\bar D^0 mixing, but rare K decays offer interesting places to search for new physics. It is probably also premature to see a clash between global C

J. -M. Gerard, J. Weyers

Trace Anomaly Dominance in weak $K$-decays successfully reproduces the $ΔI = {1\over 2}$ selection rule results, as observed in $K_S \to ππ, K_L \to πππ, K_S \to γγ$ and $K_L \to π^0 γγ$.

U. D'Alesio, F. Murgia

A unified and consistent phenomenological approach to single transverse spin asymmetries in the framework of perturbative QCD, with the inclusion of a new class of spin and k_T dependent distribution and fragmentation functions, is presented. As an example, results on A_N(p(pol) p --> pion X) and P_Lambda(p p -->Lambda(pol) X) are shown.

T. Watari, T. Yanagida

The slow roll inflation requires an extremely flat inflaton potential. The supersymmetry (SUSY) is not only motivated from the gauge hierarchy problem, but also from stabilizing that flatness of the inflaton potential against radiative corrections. However, it has been known that the Planck suppressed higher order terms in the Kähler potential receive large

Dominique Monderen

We study the lensing of neutrinos by astrophysical objects. At the difference of photons, neutrinos can cross a stellar core; as a result the lens quality improves. While Uranians alone would benefit from this effect in the Sun, similar effects could be considered for binary systems.

M. Bastero-Gil, S. F. King

We discuss leptogenesis in a realistic supersymmetric model of inflation with a low reheat temperature 1-10 GeV. The lepton asymmetry is generated by a decaying right handed sneutrino, which is produced after inflation during preheating. The inflationary model is based on a simple variant of the Next-to-Minimal Supersymmetric Standard model (NMSSM) which sol

Carlo Oleari

We briefly discuss an algorithm for the tensor reduction of the two-loop massless crossed boxes, with light-like external legs, and the computation of the relative master integrals.

Michael Dine

These lectures discuss the $θ$ parameter of QCD. After an introduction to anomalies in four and two dimensions, the parameter is introduced. That such topological parameters can have physical effects is illustrated with two dimensional models, and then explained in QCD using instantons and current algebra. Possible solutions including axions, a massless up q

Harleen Dahiya, Manmohan Gupta

The spin polarization functions $(Δu, ~Δd, ~Δs)$ for proton are calculated in the chiral quark model ($χ$QM) with SU(3) symmetry breaking as well as configuration mixing generated by one gluon exchange forces for the NMC and the most recent E866 data. Besides reproducing the spin polarization functions $Δu,Δd, Δs$ as well as $G_A/G_V$, it can accomodate nucl

Christoph Best

The construction of multigrid operators for disordered linear lattice operators, in particular the fermion matrix in lattice gauge theories, by means of algebraic multigrid and block LU decomposition is discussed. In this formalism, the effective coarse-grid operator is obtained as the Schur complement of the original matrix. An optimal approximation to it i

M. Gockeler, R. Horsley, W. Kurzinger, H. Oelrich

Our previous calculation of the spin-dependent structure function g_2 is revisited. The interest in this structure function is to a great extent motivated by the fact that it receives contributions from twist-two as well as from twist-three operators already in leading order of 1/Q^2 thus offering the unique possibility of directly assessing higher-twist eff

X. Q. Luo, E. B. Gregory, J. C. Yang, Y. L. Wang

Motivated by the computational demands of our research and budgetary constraints which are common to many research institutions, we built a ``poor man's supercomputer'', a cluster of PC nodes which together can perform parallel calculations at a fraction of the price of a commercial supercomputer. We describe the construction, cost, and performan

Jeffrey A. Appel

An increasingly large amount of quality fixed-target data on heavy-quark production at fixed-target energies is appearing. This data can provide information across a range of physics topics. The topics vary from investigations of QCD predictions to the understanding of the structure of hadrons. Recent results on neutrino, photon, and hadron production of cha

M. -H. Schune

The BABAR experiment has been taking data since about one year. Physics results, complementary to those described by G.Sciolla elsewhere in these Proceedings, are presented: various measurements of the neutral and charged B mesons lifetimes, the B^0 mixing frequency, the mistag fractions, and the B --> D_s^(*) X and B^0 --> D_s^(*)+ D^* branching ratios. Som

Marco Battaglia

Jet flavour identification in multi-TeV e+e- collisions is expected to provide insights on new phenomena at scales beyond those probed by the LHC. The anticipated high track density and jet collimation represent a new challenge to jet tagging algorithms. A method, based on the sampling of the jet charged multiplicity, sensitive to the long decay length and l

Dirk Puetzfeld

We study plane-fronted electrovacuum waves in metric-affine gravity (MAG) with cosmological constant in the triplet ansatz sector of the theory. Their field strengths are, on the gravitational side, curvature $R_α{}^β$, nonmetricity $Q_{αβ}$, torsion $T^α$ and, on the matter side, the electromagnetic field strength $F$. Here we basically present, after a sho

G. Esposito-Farese

This talk is based on my work in collaboration with B. Boisseau, D. Polarski, and A.A. Starobinsky. The most natural and best-motivated alternatives to general relativity are the so-called "scalar-tensor" theories, in which the gravitational interaction is mediated not only by a (spin-2) graviton, but also by a (spin-0) scalar field. We study quintes

G. Esposito-Farese

This talk reviews the constraints imposed by binary-pulsar data on gravity theories, and notably on "scalar-tensor" theories which are the most natural alternatives to general relativity. Because neutron stars have a strong gravitational binding energy, binary-pulsar tests are qualitatively different from solar-system experiments: They have the capab

A. V. Toporensky

The results on chaos in FRW cosmology with a massive scalar field are extended to another scalar field potential. It is shown that for sufficiently steep potentials the chaos disappears. A simple and rather accurate analytical criterion for the chaos to disappear is given. On the contrary, for gently sloping potentials the transition to a strong chaotic regi

Donald Marolf

Refined Algebraic Quantization and Group Averaging are powerful methods for quantizing constrained systems. They give constructive algorithms for generating observables and the physical inner product. This work outlines the current status of these ideas with an eye toward quantum gravity. The main goal is provide a description of outstanding problems and pos

S. Manoff, B. Dimitrov

Conditions for the existence of shear-free and expansion-free non-null vector fields in spaces with affine connections and metrics are found. On their basis Weyl's spaces with shear-free and expansion-free conformal Killing vectors are considered. The necessary and sufficient conditions are found under which a free spinless test particle could move in sp

Ted Herman, Toshimitsu Masuzawa

This paper describes a heap construction that supports insert and delete operations in arbitrary (possibly illegitimate) states. After any sequence of at most O(m) heap operations, the heap state is guarantee to be legitimate, where m is the initial number of items in the heap. The response from each operation is consistent with its effect on the data struct

Tanya Y. Berger-Wolf, Edward M. Reingold

We consider the problem of multiple description scalar quantizers and describing the achievable rate-distortion tuples in that setting. We formulate it as a combinatorial optimization problem of arranging numbers in a matrix to minimize the maximum difference between the largest and the smallest number in any row or column. We develop a technique for derivin

Norbert Broeker

This paper explores the usefulness of a technique from software engineering, code instrumentation, for the development of large-scale natural language grammars. Information about the usage of grammar rules in test and corpus sentences is used to improve grammar and testsuite, as well as adapting a grammar to a specific genre. Results show that less than half

P. E. Lammert, V. H. Crespi

The electronic structure of graphitic cones exhibits distinctive topological features associated with the apical disclinations. Aharonov-Bohm magnetoconductance oscillations (period Phi_0) are completely absent in rings fabricated from cones with a single pentagonal disclination. Close to the apex, the local density of states changes qualitatively, either de

K. Storr, L. Balicas, J. S. Brooks, D. Graf

We present an electrical transport study of the 2-dimensional (2D) organic conductor tau-(P-(S,S)-DMEDT-TTF)_2(AuBr)_2(AuBr_2)_y (y = 0.75) at low temperatures and high magnetic fields. The inter-plane resistivity rho_zz increases with decreasing temperature, with the exception of a slight anomaly at 12 K. Under a magnetic field B, both rho_zz and the in-pla

I. N. Krivorotov, K. R. Nikolaev, A. Yu. Dobin, A. M. Goldman

The effect of an exchange field on electrical transport in thin films of metallic ferromagnetic manganites has been investigated. The exchange field was induced both by direct exchange coupling in a ferromagnet/antiferromagnet multilayer and by indirect exchange interaction in a ferromagnet/paramagnet superlattice. The electrical resistance of the manganite

Joerg Schmalian, Harry Westfahl, Peter G. Wolynes

We estimate the number of metastable states of a self generated stripe glass, relevant for the formation of glassy doped Mott insulators. Using replica bound states, we demonstrate that the configurational entropy is the difference between the entropy of the stripe liquid and of an amorphous stripe solid with phonon-type excitations. Using simple scaling law

D. Stauffer, P. M. C. de Oliveira, S. Moss de Oliveira, T. J. P. Penna

The sexual version of the Penna model of biological ageing, simulated since 1996, is compared here with alternative forms of reproduction as well as with models not involving ageing. In particular we want to check how sexual forms of life could have evolved and won over earlier asexual forms hundreds of million years ago. This computer model is based on the

M. R. Sakr, Maryam Rahimi, S. V. Kravchenko

In non-interacting or weakly-interacting 2D electron systems, the energy of the extended states increases as the perpendicular magnetic field approaches zero: the extended states "float up" in energy, giving rise to an insulator. However, in those 2D systems where metallic conductivity has been recently observed in zero magnetic field, the energy of

Yu. Zadorozhny, D. R. Herman, Y. Liu

Reproducible, sample-specific magnetoresistance fluctuations (magnetic fingerprints) were observed in the low-temperature part of the superconducting transition regime of hollow Au$_{0.7}$In$_{0.3}$ cylinders of submicron diameter. The amplitude of the fluctuations was found to exceed that of the universal conductance fluctuation in normal metals by several

H. Haberland, M. Bonitz, D. Kremp

Anomalously high generation efficiency of coherent higher field-harmonics in collisions between {\em oppositely charged particles} in the field of femtosecond lasers is predicted. This is based on rigorous numerical solutions of a quantum kinetic equation for dense laser plasmas which overcomes limitations of previous investigations.

C. P. Heij, P. Hadley, J. E. Mooij

A single-electron inverter was fabricated that switches from a high output to a low output when a fraction of an electron is added to the input. For the proper operation of the inverter, the two single-electron transistors that make up the inverter must exhibit voltage gain. Voltage gain was achieved by fabricating a combination of parallel-plate gate capaci

K. Held, G. Keller, V. Eyert, D. Vollhardt

The electronic properties of paramagnetic V_2O_3 are investigated by the ab-initio computational scheme LDA+DMFT(QMC). This approach merges the local density approximation (LDA) with dynamical mean-field theory (DMFT) and uses numerically exact quantum Monte Carlo simulations (QMC) to solve the effective Anderson impurity model of DMFT. Starting with the cry

A. Andersen, C. Ellegaard, A. D. Jackson, K. Schaadt

We discuss a random matrix model of systems with an approximate symmetry and present the spectral fluctuation statistics and eigenvector characteristics for the model. An acoustic resonator like, e.g., an aluminium plate may have an approximate symmetry. We have measured the frequency spectrum and the widths for acoustic resonances in thin aluminium plates,

Myung-Hoon Chung

A model Hamiltonian is proposed in order to understand the localization-delocalization transition in a quantum dot, where there are two gate voltages: top and side. Considering energetically favorable degrees of freedom only, we achieve a finite dimensional Hilbert space. As a result, exact diagonalization is performed to find the ground state energy of the

Jon Hakkila, Richard J. Roiger, David J. Haglin, Robert S. Mallozzi

Gamma-ray bursts provide what is probably one of the messiest of all astrophysical data sets. Burst class properties are indistinct, as overlapping characteristics of individual bursts are convolved with effects of instrumental and sampling biases. Despite these complexities, data mining techniques have allowed new insights to be made about gamma-ray burst d

David S. Meier, Jean L. Turner, Lucian P. Crosthwaite, Sara C. Beck

Eight dwarf starburst galaxies have been observed with the Caltech Submillimeter Observatory (CSO) telescope in the CO J= 3 - 2 transition. The galaxies observed are He 2-10, NGC 5253, NGC 1569, NGC 3077, Haro 2, Haro 3, II Zw 40 and Mrk 86; all but the last two are detected. The central regions of He 2-10 and NGC 5253 were mapped and a CO(2-1) spectrum of N

C. L. Brogan, T. H. Troland

We report VLA HI Zeeman observations toward the W49A star-forming region and the SNR W49B. Line of sight magnetic fields (Blos) of 60 to 300 muG at 25" resolution were detected toward W49A at velocities of ~4 and ~7 km/s. The Blos values measured toward W49A show a significant increase in field strength with higher resolution especially for the ~4 km/s H

Axel Brandenburg

A number of problems of solar and stellar dynamo theory are briefly reviewed and the current status of possible solutions is discussed. Results of direct numerical simulations are described in view of mean-field dynamo theory and the relation between the alpha-effect and the inverse cascade of magnetic helicity is highlighted. The possibility of `catastrophi