December 1999 arXiv papers — page 7

Joel S. Bader, Richard W. Hammond, Steven A. Henck, Michael W. Deem

We have micromachined a silicon-chip device that transports DNA with a Brownian ratchet that rectifies the Brownian motion of microscopic particles. Transport properties for a DNA 50mer agree with theoretical predictions, and the DNA diffusion constant agrees with previous experiments. This type of micromachine could provide a generic pump or separation comp

Nima Arkani-Hamed, Lawrence Hall, David Smith, Neal Weiner

In theories with (sets of) two large extra dimensions and supersymmetry in the bulk, the presence of non-supersymmetric brane defects naturally induces a logarithmic potential for the volume of the transverse dimensions. Since the logarithm of the volume rather than the volume itself is the natural variable, parameters of O(10) in the potential can generate

G. Arutyunov, S. Frolov

All quartic couplings of scalar fields $s^I$ that are dual to extended chiral primary operators in ${\cal N}=4$ SYM$_4$ are derived by using the covariant equations of motion for type IIB supergravity on $AdS_5\times S^5$. It is shown that despite some expectations if one keeps the structure of the cubic terms untouched, the quartic action obtained contains

Willem T. H. van Oers

Time-Reversal-Invariance non-conservation has now been unequivocally demonstrated in a direct measurement at CPLEAR. What about tests of time-reversal-invariance in systems other than the kaon system? Tests of time-reversal-invariance belong to two classes: searches for parity violating (P-odd)/time-reversal-invariance-odd (T-odd) interactions, and for P-eve

Eliot Quataert, Andrei Gruzinov

Non-radiating, advection-dominated, accretion flows are convectively unstable. We calculate the two-dimensional (r-theta) structure of such flows assuming that (1) convection transports angular momentum inwards, opposite to normal viscosity and (2) viscous transport by other mechanisms (e.g., magnetic fields) is weak (alpha << 1). Under such conditions conve

A. C. Quillen, Colleen McDonald, A. Alonso-Herrero, Ariane Lee

We examine 112 Seyfert galaxies observed by the Hubble Space Telescope (HST) at 1.6 microns. We find that ~50% of the Seyfert 2.0 galaxies which are part of the Revised Shapeley-Ames (RSA) Catalog or the CfA redshift sample contain unresolved continuum sources at 1.6 microns. All but a couple of the Seyfert 1.0-1.9 galaxies display unresolved continuum sourc

A. C. Quillen, Shanna Shaked, A. Alonso-Herrero, Colleen McDonald

We present a study of Seyfert 1.5-2.0 galaxies observed at two epochs with the Hubble Space Telescope (HST) at 1.6 microns. We find that unresolved nuclear emission from 9 of 14 nuclei varies at the level of 10-40% on timescales of 0.7-14 months, depending upon the galaxy. A control sample of Seyfert galaxies lacking unresolved sources and galaxies lacking S

Alakabha Datta, Xinmin Zhang

We take the standard model to be an effective theory including higher dimensional operators suppressed by scale $Λ$ and re-examine the higgs mass bounds from the requirements of vacuum stability. Our results show that the effects of the higher dimensional operators on the higgs mass limits are significant. As an implication of our results, we study the vacuu

Ulf H. Danielsson, Esko Keski-Vakkuri, Martin Kruczenski

We investigate black hole formation by a spherically collapsing thin shell of matter in AdS space. This process has been suggested to have a holographic interpretation as thermalization of the CFT on the boundary of the AdS space. The AdS/CFT duality relates the shell in the bulk to an off-equilibrium state of the boundary theory which evolves towards a ther

A. H. MacDonald

The spin degree of freedom can play an essential role in determining the electrical transport properties of spin-polarized electron systems in metals or semiconductors. In this article, I address the dependence of spin-subsystem chemical potentials on accumulated spin-densities. I discuss both approaches which can be used to measure this fundamental thermody

P Kirk, C Livingston

We provide a framework for studying the interplay between concordance and positive mutation and identify some of the basic structures relating the two. The fundamental result in understanding knot concordance is the structure theorem proved by Levine: for n>1 there is an isomorphism phi from the concordance group C_n of knotted (2n-1)-spheres in S^{2n+1} to

U. Magnea

In this paper we complete the derivations of finite volume partition functions for QCD using random matrix theories by calculating the effective low-energy partition function for three-dimensional QCD in the adjoint representation from a random matrix theory with the same global symmetries. As expected, this case corresponds to Dyson index $β=4$, that is, th

L. Benet, F. M. Izrailev, T. H. Seligman, A. Suarez-Moreno

Quantum-classical correspondence for the shape of eigenfunctions, local spectral density of states and occupation number distribution is studied in a chaotic model of two coupled quartic oscillators. In particular, it is shown that both classical quantities and quantum spectra determine global properties of occupation numbers and inverse participation ratio.

W. Siegel

The first free comprehensive textbook on quantum (and classical) field theory. The approach is pragmatic, rather than traditional or artistic: It includes practical techniques, such as the 1/N expansion (color ordering) and spacecone (spinor helicity), and diverse topics, such as supersymmetry and general relativity, as well as introductions to supergravity

Fernando C. Lombardo, Francisco D. Mazzitelli, Diana Monteoliva

We analyze the quantum to classical transition of the order parameter in second order phase transitions. We consider several toy models in non relativistic quantum mechanics. We study the dynamical evolution of a wave packet initially peaked around a local maximum of the potential using variational approximations and also exact numerical results. The influen

Ramesh Narayan, Igor V. Igumenshchev, Marek A. Abramowicz

We consider height-integrated equations of an advection-dominated accretion flow (ADAF), assuming that there is no mass outflow. We include convection through a mixing length formalism. We seek self-similar solutions in which the rotational velocity and sound speed scale as R^{-1/2}, where R is the radius, and consider two limiting prescriptions for the tran

Ralph Blumenhagen, Lars Goerlich, Boris Kors

We study a certain class of four-dimensional N=1 supersymmetric orientifolds for which the world-sheet parity transformation is combined with a complex conjugation in the compact directions. We investigate in detail the orientifolds of the Z_3, Z_4, Z_6 and Z_6&#39; toroidal orbifolds finding solutions to the tadpole cancellation conditions for all models. G

D. Semkat, D. Kremp, M. Bonitz

A recently developed method for incorporating initial binary correlations into the Kadanoff-Baym equations (KBE) is used to derive a generalized T-matrix approximation for the self-energies. It is shown that the T-matrix obtains additional contributions arising from initial correlations. Using these results and taking the time-diagonal limit of the KBE, a ge

Masud Chaichian, Archil B. Kobakhidze

We argue that the familiar gauge hierarchy between the fundamental Planck scale M_{Pl} and the electroweak scale M_{W}, can be naturally explained in higher dimensional theories with relatively large radii (R_c > 1/M_{Pl}) extra dimensions. In particular, we show that it is possible that the electroweak Higgs mass at high energies is of the order of M_{Pl},

Gerald Dunne, Joshua Feinberg

We compute the CP-odd part of the finite temperature effective action for massive Dirac fermions in the presence of a Dirac monopole. We confirm that the induced charge is temperature dependent, and in the effective action we find an infinite series of CP-violating terms that generalize the familiar zero temperature $F\tilde{F}$ term. These results are analo

Carsten Timm, P. J. Jensen

Ferromagnetic thin films with magnetic single-ion anisotropies are studied within the framework of Schwinger bosonization of a quantum Heisenberg model. Two alternative bosonizations are discussed. We show that qualitatively correct results are obtained even at the mean-field level of the theory, similar to Schwinger boson results for other magnetic systems.

Yu. V. Kozlov, S. V. Khalturtsev, I. N. Machulin, A. V. Martemyanov

This report is represented the results of some experiments, which carried out at the neutrino underground laboratory of Kranoyarsk nuclear plant.

V. A. Maisheev

It is shown that single crystals are sensitive to the initial circular polarization of gamma-quanta with energies in tens GeV and more. The possibility of measurement of gamma-beam polarization is discussed. The obtained results may be useful for creation of polarimeters for high energy beams of gamma-quanta.

Yu. V. Kozlov, S. V. Khalturtsev, I. N. Machulin, A. V. Martemyanov

The results of undergoing experiments and new experiment propositions at Krasnoyarsk underground nuclear reactor are presented

Chiang-Mei Chen, T. Harko, M. K. Mak

The dynamics and evolution of Bianchi type I space-times is considered in the framework of the four-dimensional truncation of a reduced theory obtained from the N=2,D=5 supergravity. The general solution of the gravitational field equations can be represented in an exact parametric form. All solutions have a singular behavior at the initial/final moment, exc

Z. Chacko, A. E. Nelson

We construct a class of solutions to the Einstein&#39;s equations for dimensions greater than or equal to six. These solutions are characterized by a non-trivial warp factor and possess a non-compact extra dimension. We study in detail a simple model in six dimensions containing two four branes. One of each brane&#39;s four spatial directions is compactified

Daigen Fukayama, Toshihiro Oyamada, Tohru Nakano, Toshiyuki Gotoh

In order to reliably compute the longitudinal structure functions in decaying and forced turbulence, local isotropy is examined with the aid of the isotropic expression of the incompressible conditions for the second and third order structure functions. Furthermore, the Karman-Howarth-Kolmogorov relation is investigated to examine the effects of external for

Shin&#39;ichi Nojiri, Sergei D. Odintsov, Sachiko Ogushi

Using AdS/CFT correspondence we found the conformal anomaly from d3 and d5 gauged supergravity with single scalar (dilaton) and the arbitrary scalar potential on AdS-like scalar-gravitational background. Such dilatonic gravity action describes the special RG flows in extended gauged SG when scalars lie in one-dimensional submanifold of complete scalars space

Rong Lu, Su-Peng Kou, Jia-Lin Zhu, Lee Chang

The quantum tunneling of the magnetization vector between excited levels are studied theoretically in single-domain ferromagnetic nanoparticles with biaxial crystal symmetry placed in an external magnetic field at an arbitarily directed angle in the ZX plane. The temperature dependences of the tunneling frequency and the decay rate are clearly shown for each

Arash Mafi, Stuart Raby

In this paper we consider a heavy gluino to be the lightest supersymmetric particle [LSP]. We investigate the limits on the mass of a heavy gluino LSP, using the searches for excess events in the jets plus missing momentum channel in Run I. The neutral and charged R-hadrons, containing a heavy gluino LSP, have distinct signatures at the Fermilab Tevatron. Th

Emanuel Scheidegger

D-branes on one-parameter Calabi-Yau spaces and two-parameter K3-fibered Calabi-Yau manifolds are analyzed from both the Gepner model point of view and the geometric perspective. We compute part of the spectrum of the boundary states and comment on the appearance of the D0-brane as well as on nonsupersymmetric large volume configurations becoming supersymmet

A. B. Kaidalov, Yu. A. Simonov

Using a nonperturbative method based on asymptotic behaviour of Wilson loops we calculate masses of glueballs and corresponding Regge-trajectories. The method contains no fitting parameters and the mass scale is fixed by the meson Regge slope. Theoretical predictions for lowest glueball states are in a perfect agreement with lattice results. The leading glue

Masanori Ohya, Igor V. Volovich

An approach to the solution of NP-complete problems based on quantum computing and chaotic dynamics is proposed. We consider the satisfiability problem and argue that the problem, in principle, can be solved in polynomial time if we combine the quantum computer with the chaotic dynamics amplifier based on the logistic map. We discuss a possible implementatio

George Svetlichny

Lorentz covariance imposed upon a quantum logic of local propositions for which all observers can consistently maintain state collapse descriptions, implies a condition on space-like separated propositions that if imposed on generally commuting ones would lead to the covering law, and hence to a hilbert-space model for the logic. Such a generalization can be

Piotr Badziag, Michal Horodecki, Pawel Horodecki, Ryszard Horodecki

We show how an interaction with the environment can enhance fidelity of quantum teleportation. To this end, we present examples of states which cannot be made useful for teleportation by any local unitary transformations; nevertheless, after being subjected to a dissipative interaction with the local environment, the states allow for teleportation with genui

D. O&#39;Dell, S. Giovanazzi, G. Kurizki, V. M. Akulin

We show that particular configurations of intense off-resonant laser beams can give rise to an attractive 1/r interatomic potential between atoms located well within the laser wavelength. Such a ``gravitational-like&#39;&#39; interaction is shown to give stable Bose condensates that are self-bound (without an additional trap) with unique scaling properties a

K. Kowalski, J. Rembielinski

The coherent states for a particle on a sphere are introduced. These states are labelled by points of the classical phase space, that is the position on the sphere and the angular momentum of a particle. As with the coherent states for a particle on a circle discussed in Kowalski K {\em et al} 1996 {\em J. Phys. A} {\bf 29} 4149, we deal with a deformation o

M. N. Mazziotta

A full simulation of a transition radiation detector (TRD) based on the GEANT, GARFIELD, MAGBOLTZ and HEED codes has been developed. This simulation can be used to study and develop TRD for high energy particle identification using either the cluster counting or the total charge measurement method. In this article it will be also shown an application of this

J. Ortner

The dynamic sructure factor as the basic quantity describing the collective excitations in a fluid is considered. We consider the cases of neutral and Coulombic fluids. The classical method of moments is applied to construct the dynamic structure factor satisfying all known sum rules. An interpolational formula is found which expresses the dynamic characteri

A. C. V. Ceapa

Considerations on the complementary time-dependent coordinate transformations emboding Lorentz transformation (LT) show that the relativistic energy-momentum relationship, implicitly the relativistic mass and energy, do not depend on the square root appearing in LT, being associated to the absolute motion of a particle and related to its inner structure. Res

Karen E. Daniels, Eberhard Bodenschatz

We report experiments on thermally driven convection in an inclined layer of large aspect ratio in a fluid of Prandtl number $σ\approx 1$. We observed a number of new nonlinear, mostly spatio-temporally chaotic, states. At small angles of inclination we found longitudinal rolls, subharmonic oscillations, Busse oscillations, undulation chaos, and crawling rol

Monika E. Pietrzyk

Properties of two pulses propagating simultaneously in different dispersion regimes, anomalous and normal, in a Kerr-type planar waveguide are studied in the framework of the nonlinear Schroedinger equation. Catastrophic self-focusing and spatio-temporal splitting of the pulses is investigated. For the limiting case when the dispersive term of the pulse prop

Mariane Mangin-Brinet, Jaume Carbonell

We study relativistic effects in a system of two scalar particles interacting via a scalar exchange in the Light Front Dynamcis framework. The results are compared to those provided by Bethe-Salpeter and non relativistic equations. It is found in particular that for massive exchange, the relativistic description is of crucial importance even in the limit of

A. P. Kobushkin

We study how d+3He beckward elastic scattering is connected with momentum distribution of the deuteron in 3He. With this aim th relativistic calculations in the framework of proton exchange is investigated. We also consider possible reaction mechanisms beyond the proton exchange

R. J. Furnstahl, Brian D. Serot

In nonrelativistic models of nuclei, the underlying mass scales of low-energy quantum chromodynamics (QCD) are largely hidden. In contrast, the covariant formulations used in relativistic phenomenology manifest the QCD scales in nuclei through large Lorentz scalar and four-vector nucleon self-energies. The abundant and varied evidence in support of this conn

Y. Fujiwara, M. Kohno, T. Fujita, C. Nakamoto

The quark-model hyperon-nucleon interaction suggests an important antisymmetric spin-orbit component. It is generated from a color analogue of the Fermi-Breit interaction dominating in the one-gluon exchange process between quarks. We discuss the strength S_B of the single-particle spin-orbit potential, following the Scheerbaum&#39;s prescription. Using the

Nikolai Chernov, Dmitry Kleinbock

Let $T: X\mapsto X$ be a deterministic dynamical system preserving a probability measure $μ$. A dynamical Borel-Cantelli lemma asserts that for certain sequences of subsets $A_n\subset X$ and $μ$-almost every point $x\in X$ the inclusion $T^nx\in A_n$ holds for infinitely many $n$. We discuss here systems which are either symbolic (topological) Markov chain

Michael T. Anderson

Several rigidity results are proved for critical points of natural Riemannian functionals on the space of metrics on 3-manifolds. Two of these results are as follows. Let (N, g) be a complete Riemannian 3-manifold, satisfying one of the following variational conditions: (i) (N, g) has non-negative scalar curvature and is a critical point for the L^2 norm of

Sadok Kallel, Denis Sjerve

In this paper we determine all finite groups G that can act on some compact Riemann surface M with the property that if H is any non-trivial subgroup of G, then the orbit surface M/H is the Riemann sphere. The idea is to look at the induced action on the vector space of holomorphic differentials on M (in the positive genus case) and then use the old-known (W

Kefeng Liu, Xiaonan Ma, Weiping Zhang

We prove several vanishing theorems for a class of generalized elliptic genera on foliated manifolds, by using classical equivariant index theory. The main techniques are the use of the Jacobi theta-functions and the construction of a new class of elliptic operators associated to foliations.

B. Toen

Based on the methods used by the author to prove the Riemann-Roch formula for algebraic stacks, this paper contains a description of the rationnal G-theory of Deligne-Mumford stacks over general bases. We will use these results to study equivariant K-theory, and also to define new filtrations on K-theory of algebraic stacks.

P. Biane, J. Pitman, M. Yor

This paper reviews known results which connect Riemann&#39;s integral representations of his zeta function, involving Jacobi&#39;s theta function and its derivatives, to some particular probability laws governing sums of independent exponential variables. These laws are related to one-dimensional Brownian motion and to higher dimensional Bessel processes. We

Mattias Dahl

We study the dependence of the eta invariant $η_D$ on the spin structure, where $D$ is a twisted Dirac operator on a (4k+3)-dimensional spin manifold. The difference between the eta invariants for two spin structures related by a cohomolgy class which is the reduction of a $H^1(M,\Za)$-class is shown to be a half integer. As an application of the technique o

Eugene Z. Xia

For a compact Riemann surface $X$ of genus $g > 1$, $\Hom(π_1(X), U(p,1))/U(p,1)$ is the moduli space of flat $\U(p,1)$-connections on $X$. There is an integer invariant, $τ$, the Toledo invariant associated with each element in $\Hom(π_1(X), U(p,1))/U(p,1)$. If $q = 1$, then $-2(g-1) \le τ\le 2(g-1)$. This paper shows that $\Hom(π_1(X), U(p,1))/U(p,1)$ has

Zygmunt Lalak, Stéphane Lavignac, Hans Peter Nilles

We study the implications of target-space duality symmetries for low-energy effective actions of various four-dimensional string theories. In the heterotic case such symmetries can be incorporated in simple orbifold examples. At present a similar statement cannot be made about the simplest type IIB orientifolds due to an obstruction at the level of gravitati

Luca Lusanna

Talk given at the International Workshop ``Physical Variables in Gauge Theories&#34;, Dubna 1999

G. Bandelloni, S. Lazzarini

It is shown how $W$-algebras emerge from very peculiar canonical transformations with respect to the canonical symplectic structure on a compact Riemann surface. The action of smooth diffeomorphisms of the cotangent bundle on suitable generating functions is written in the BRS framework while a $W$-symmetry is exhibited. Subsequently, the complex structure o

C. Bizdadea, E. M. Cioroianu, S. O. Saliu

An irreducible Hamiltonian BRST approach to topologically coupled p- and (p+1)-forms is developed. The irreducible setting is enforced by means of constructing an irreducible Hamiltonian first-class model that is equivalent from the BRST point of view to the original redundant theory. The irreducible path integral can be brought to a manifestly Lorentz covar

C. Bizdadea, I. Negru, S. O. Saliu

The irreducible Hamiltonian BRST symmetry for p-form gauge theories with Stueckelberg coupling is derived. The cornerstone of our approach is represented by the construction of an irreducible theory that is equivalent from the point of view of the BRST formalism with the original system. The equivalence makes permissible the substitution of the BRST quantiza

C. Bizdadea, I. Negru, S. O. Saliu

The irreducible BRST symmetry for the Freedman-Townsend model is derived. The comparison with the standard reducible approach is also addressed.

C. Bizdadea, I. Negru, S. O. Saliu

In this paper we develop an irreducible antifield BRST-anti-BRST formalism for reducible gauge theories.

C. Bizdadea, S. O. Saliu

An irreducible antifield BRST quantization method for reducible gauge theories is proposed. The general formalism is illustrated in the case of the Freedman-Townsend model.

O. A. Castro-Alvaredo, A. Fring, C. Korff, J. L. Miramontes

We apply the thermodynamic Bethe Ansatz to investigate the high energy behaviour of a class of scattering matrices which have recently been proposed to describe the Homogeneous sine-Gordon models related to simply laced Lie algebras. A characteristic feature is that some elements of the suggested S-matrices are not parity invariant and contain resonance shif

V. Dzhunushaliev, D. Singleton

In this paper we apply a variant of Heisenberg&#39;s quantization method for strongly interacting, non-linear fields, to solutions of the classical Yang-Mills field equations which have bad asymptotic behavior. After quantization we find that the bad features (i.e. divergent fields and energy densities) of these solutions are moderated. From these results we

Mirjam Cvetic, Jing Wang

We study local and global gravitational effects of (D-2)-brane configurations (domain-walls) in the vacuum of D-dimensional space-time. We focus on infinitely thin vacuum domain walls with arbitrary cosmological constants on either side of the wall. In the comoving frame of the wall we derive a general metric Ansatz, consistent with the homogeneity and isotr

Xavier Bekaert

Two issues regarding the interactions of the chiral two-forms are reviewed. First, the problem of constructing Lorentz-invariant self-couplings of a single chiral two-form is investigated in the light of the Dirac-Schwinger condition on the energy-momentum tensor commutation relations. We show how the Perry-Schwarz condition follows from the Dirac-Schwinger

Robert Bluhm, Alan Kostelecky, Charles Lane

Precision experiments with muons are sensitive to Planck-scale CPT and Lorentz violation that is undetectable in other tests. Existing data on the muonium ground-state hyperfine structure and on the muon anomalous magnetic moment could be analyzed to provide dimensionless figures of merit for CPT and Lorentz violation at the levels of $4\times 10^{-21}$ and

Douglas J. Buettner, P. D. Morley, Ivan Schmidt

We investigate the possible occurrence of extra spatial dimensions (D = 3+epsilon) in the early universe. A detailed calculation is presented which shows that the crucial signal is the apparent inequality of the cosmological Z-term between matching Lyman alpha (Ly{alpha}) and Lyman beta (Ly{beta}) spectral lines, both emission and absorption, when using the

A. Denner, S. Dittmaier, M. Roth, D. Wackeroth

We present numerical results for total cross sections and various distributions for e+e- --> WW --> 4f(+gamma) at a future 500GeV linear collider, obtained from the Monte Carlo generator RACOONWW. This generator is the first one that includes O(alpha) electroweak radiative corrections in the double-pole approximation completely. Owing to their large size the

J. Wirstam

We study the chiral symmetry in two-color QCD with N massless flavors at finite temperature, using an effective theory. For the gauge group SU(2), the chiral symmetry is enlarged to SU(2N), which is then spontaneously broken to Sp(2N) at zero temperature. At finite temperature, and when the axial anomaly can be neglected, we find a first order phase transiti

R. D. Ball, P. V. Landshoff

We review the current understanding of the behaviour of inclusive cross sections at small x and large Q^2 in terms of Altarelli-Parisi evolution, the BFKL equation, and Regge theory, asking in particular to what extent they are mutually consistent.

Stephen Godfrey, Pat Kalyniak, Basim Kamal, Arnd Leike

If extra gauge bosons are observed at the LHC or at a linear e+e- collider, the reaction e+e- --> nu nubar gamma can give information on the couplings (W&#39; nu l) and (Z&#39; nu nubar). The total cross section and polarization asymmetries are the most sensitive observables for such a measurement. Small systematic errors are crucial to obtain reasonable cou

Marc Knecht

Several new theoretical and experimental developments concerning the determination of the nucleon sigma term are presented and discussed. Contribution to the Eighth International Symposium on Meson-Nucleon Physics and the Structure of the Nucleon, Zuoz, Engadine, Switzerland, August 15-21 1999.

Marc Knecht

Electromagnetic corrections to the low-energy pi+ pi- -> pi0 pi0 scattering amplitude at next-to-leading order in the chiral expansion are reviewed. Their effects on the corresponding scattering lengths are estimated and compared to the two-loop strong interaction contributions. Contribution to the proceedings of the Eighth International Symposium on Meson-N

G. P. Vacca

Our aim is to show how the reggeization of the gluon, encoded in the bootstrap property of the BFKL kernel, permits to calculate the interaction kernel in the octet colour channel in the forward and non forward direction, for the quark contribution, starting from the known gluon trajectory up to 2nd order. To this end an ansatz to solve the bootstrap equatio

M. Botje

The parton momentum density distributions in the proton are determined from a next-to-leading order QCD analysis of structure functions measured at HERA and by fixed target experiments. Also included are data on the difference of the up and down anti-quark distributions. The uncertainties in the parton densities, structure functions and related cross section

P. F. Harrison, W. G. Scott

Terrestrial matter effects in neutrino propagation are T-invariant, so that any observed T violation when neutrinos pass through the Earth, such as an asymmetry between the transition probabilities P(nu_mu -> nu_e) and P(nu_e -> nu_mu), would be a direct indication of T violation at the fundamental level. Matter effects do however modify the magnitudes of T-

M. Atance, B. Schrempp

In the framework of the low energy Chiral Lagrangian, the renormalization group equations for the couplings are investigated up to order p^6, both for the SU(2) as for the SU(3) cases. Infrared attractive fixed points for ratios of couplings are found. These fixed points solutions turn out to agree with the values determined from experiment in a large number

Achim Bode, Urs M. Heller, Robert G. Edwards, Rajamani Narayanan

We describe an HMC algorithm for dynamical overlap fermions which makes use of their good chiral properties. We test the algorithm in the Schwinger model. Topological sectors are readily changed even in the massless case.

Robert G. Edwards, Urs M. Heller, Joe Kiskis, Rajamani Narayanan

We briefly review the overlap formalism for chiral gauge theories, the overlap Dirac operator for massless fermions and its connection to domain wall fermions. We describe properties of the overlap Dirac operator, and methods to implement it numerically. Finally, we give some examples of quenched calculations of chiral symmetry breaking and topology with ove

I. T. Drummond, N. A. Goodman, R. R. Horgan, H. P. Shanahan

We present a quenched calculation of lowest bottomonium hybrid states on an anisotropic lattice with Landau mean-link tadpole improvement, using the improved NRQCD Hamiltonian. We investigate the quark-spin s=0,1 sectors, which contain both the non-exotic 1-- and the exotic 1-+, and demonstrate their degeneracy in the case of the lowest order Hamiltonian. Bo

Artan Borici

In this talk I will emphasize the role of the Truncated Overlap Fermions in showing the equivalence between the Domain Wall and Overlap Fermions up to an irrelevant factor in the fermionic integration measure. I will also show how Domain Wall type fermions with a finite number of flavors can be used to accelerate propagator calculations of their light partne

M. Bartels, G. Mack, G. Palma

Polyakov&#39;s calculation of the effective action for the 2d nonlinear sigma-Model is generalized by purely analytic means to include contributions which are not UV-divergent and which depend on the choice of block spin. An analytic approximation to the background field which determines the classical perfect action is given, and approximations to the 1-loop

F. Berruto, G. Grignani, P. Sodano

We study the strong coupling limit of the one-flavor and two-flavor massless &#39;t Hooft models, $large-{\cal N}_c$-color $QCD_2$, on a lattice. We use staggered fermions and the Hamiltonian approach to lattice gauge theories. We show that the one-flavor model is effectively described by the antiferromagnetic Ising model, whose ground state is the vacuum of

S. Petrarca

In this talk I briefly comment on the conventional lattice gauge fixing adopting a critical, even though constructive, numerical point of view.

L. Giusti, M. L. Paciello, S. Petrarca, B. Taglienti

In this poster we present a few preliminary results obtained using our method to fix generic covariant gauges on the lattice. We have computed the gluon propagator and we have found a sensitive dependence on the gauge parameter.

Richard Nisius

The present knowledge of the structure of the photon is presented with emphasis on measurements of the photon structure obtained from deep inelastic electron-photon scattering at e+e- colliders. This review covers the leptonic and hadronic structure of quasi-real and also of highly virtual photons, based on measurements of structure functions and differentia

Laurel Sinclair

A pedagogical introduction to the experimental results on hard photoproduction at HERA is provided. Then the latest results in this field from ZEUS and H1 are reviewed.

Thibault Damour, Piotr Jaranowski, Gerhard Schäfer

We extract all the invariants (i.e. all the functions which do not depend on the choice of phase-space coordinates) of the dynamics of two point-masses, at the third post-Newtonian (3PN) approximation of general relativity. We start by showing how a contact transformation can be used to reduce the 3PN higher-order Hamiltonian derived by Jaranowski and Schäfe

Luca Lusanna

Talk given at the Conference ``Constrained Dynamics and Quantum Gravity 99&#39;&#39;, Villasimius (Sardinia, Italy), September 13-17, 1999

H. F. Dowker, R. S. Garcia, S. Surya

The causal relation $K^+$ was introduced by Sorkin and Woolgar to extend the standard causal analysis of $C^2$ spacetimes to those that are only $C^0$. Most of their results also hold true in the case of spacetimes with degeneracies. In this paper we seek to examine $K^+$ explicitly in the case of Lorentzian topology changing Morse spacetimes containing isol

A. Feoli, G. Lambiase, G. Papini, G. Scarpetta

We consider a model in which accelerated particles experience line--elements with maximal acceleration corrections. When applied to the Schwarzschild metric, the effective field experienced by accelerated test particles contains corrections that vanish in the limit $\hbar\to 0$, but otherwise affect the behaviour of matter greatly. A new effect appears in th

İ. Yılmaz, İ. Yavuz, H. Baysal, İ. Tarhan

We study, in this paper, curvature inheritance symmetry (CI), $£_ξR_{bcd}^{a}=2αR_{bcd}^{a}$, where $α$ is a scalar function, for string cloud and string fluid in the context of general relativity. Also, we have obtained some result when a proper CI (i.e., $α\neq 0$) is also a conformal Killing vector.

J. M. Pons, D. C. Salisbury, L. C. Shepley

We construct explicitly generators of projectable four-dimensional diffeomorphisms and triad rotation gauge symmetries in a model of vacuum gravity where the fundamental dynamical variables in a Palatini formulation are taken to be a lapse, shift, densitized triad, extrinsic curvature, and the time-like components of the Ricci rotation coefficient. Time-foli

Alexander Gromov, Yurij Baryshev, Daniel J Suson, Pekka Teerikorpi

We start a systematic study of the Lemaître-Tolman-Bondi (LTB) model as applied to the large scale structure and its evolution. Here we study three possible initial conditions of the LTB models which are asymptotically FRW at large scales: bang time, fractal density (with fractal dimension D=2), and velocity law. Any two of these determine the third one. Fra

R. N. Bhatt, Xin Wan

We describe a Monte Carlo simulation study of the magnetic phase diagram of diluted magnetic semiconductors doped with shallow impurities in the low concentration regime. We show that because of a wide distribution of interaction strengths, the system exhibits strong quantum effects in the magnetically ordered phase. A discrete spin model, found to closely a

Alexei A. Abrikosov

A model of superconductivity in layered high-temperature superconducting cuprates is proposed, based on the extended saddle point singularities in the electron spectrum, weak screening of the Coulomb interaction and phonon-mediated interaction between electrons plus a small short -range repulsion of Hund&#39;s, or spin-fluctuation, origin. This permits to ex

Jungsoo Kim, D. Coffey

We calculate the single-particle Green&#39;s function for the tight-binding band structure, $ξ_{\vec p}=-2t\cos p_x-2t\cos p_y -μ$, with a function of chemical potential $μ$ for square-lattice system. The form of the single-particle self-energy, $Σ({\vec p}, E)$, is determined by the density-density correlation function, $χ({\vec q}, ω)$, which develops two

Johannes Voit, Yupeng Wang, Marco Grioni

We show that one-dimensional quantum systems with gapless degrees of freedom and open boundary conditions form a new universality class of quantum critical behavior, which we propose to call ``bounded Luttinger liquids&#39;&#39;. They share the following properties with ordinary (periodic) Luttinger liquids: absence of fermionic quasi-particle excitations, c

S. Suellow, I. Prasad, S. Bogdanovich, M. C. Aronson

We present a magnetotransport study of the low--carrier density ferromagnet EuB_6. This semimetallic compound, which undergoes two ferromagnetic transitions at T_l = 15.3 K and T_c = 12.5 K, exhibits close to T_l a colossal magnetoresistivity (CMR). We quantitatively compare our data to recent theoretical work, which however fails to explain our observations