September 2000 arXiv papers — page 3

U. Leonhardt, P. Piwnicki

We review the theory of light propagation in moving media with extremely low group velocity. We intend to clarify the most elementary features of monochromatic slow light in a moving medium and, whenever possible, to give an instructive simplified picture.

Vladimir S. Ilchenko, Michael L. Gorodetsky, X. Steve Yao, Lute Maleki

We have demonstrated a 165 micron oblate spheroidal microcavity with free spectral range 383.7 GHz (3.06nm), resonance bandwidth 25 MHz (Q ~ 10^7) at 1550nm, and finesse F > 10^4. The highly oblate spheroidal dielectric microcavity combines very high Q-factor, typical of microspheres, with vastly reduced number of excited whispering-gallery (WG) modes (by tw

A. Lipsich, S. Barreiro, P. Valente, A. Lezama

Electromagnetically induced absorption (EIA) was observed on a sample of $% ^{85}Rb$ in a magneto-optical trap using low intensity cw copropagating pump and probe optical fields. At moderate trapping field intensity, the EIA spectrum is determined by the Zeeman effect produced on the atomic ground-state by the trapping quadrupolar magnetic field. The use of

U. D. Jentschura, P. J. Mohr, G. Soff

A nonperturbative numerical evaluation of the one-photon electron self energy for the K- and L-shell states of hydrogenlike ions with nuclear charge numbers Z=1 to 5 is described. Our calculation for the 1S state has a numerical uncertainty of 0.8 Hz in atomic hydrogen, and for the L-shell states (2S and 2P) the numerical uncertainty is 1.0 Hz. The method of

Constantin Brif, Herschel Rabitz

We propose a formalism for extracting molecular Hamiltonian structure from inversion of time-dependent fluorescence intensity data. The proposed method requires a minimum of \emph{a priori} knowledge about the system and allows for extracting a complete set of information about the Hamiltonian for a pair of molecular electronic surfaces.

J. E. Garcia-Ramos, C. De Coster, R. Fossion, K. Heyde

In the framework of the interacting boson model the three transitional regions (rotational-vibrational, rotational-$γ$-unstable and, vibrational-$γ$-unstable transitions) are reanalyzed. A new kind of plot is presented for studying phase transitions in finite systems such as atomic nuclei. The importance of analyzing binding energies and not only energy spec

S. Marcos, L. N. Savushkin, M. Lopez-Quelle, R. Niembro

We investigate the origin of the kink effect (KE) in the relativistic mean field theory by transforming the single-particle Dirac equation into a Schrodinger-like equation. It is found that relativistic self-consistent effects as well as contributions from the rho meson determine the actual structure of the KE. However, the spin-orbit force generated by the

M. Betigeri, J. Bojowald, A. Budzanowski, A . Chatterjee

The production of neutral and charged pions as well as eta mesons is studied in the Delta and N* resonance region, respectively. Heavy A=3 recoils were measured with the GEM detector. The differential cross sections covering the full angular range are compared with model calculations.

Alex Roxin, Hermann Riecke

{We study a model of small-amplitude traveling waves arising in a supercritical Hopf-bifurcation, that are coupled to a slowly varying, real field. The field is advected by the waves and, in turn, affects their stability via a coupling to the growth rate. In the absence of dispersion we identify two distinct shortwave instabilities. One instability induces a

J. Suzuki

Recently, a remarkable correspondence has been unveiled between a certain class of ordinary linear differential equations (ODE) and integrable models. In the first part of the report, we survey the results concerning the 2nd order differential equations, the Schroedinger equation with a polynomial potential. We will observe that fundamental objects in the st

Alfredo Iorio, Giuseppe Vitiello

We study the canonical quantization of the damped harmonic oscillator by resorting to the realization of the q-deformation of the Weyl-Heisenberg algebra (q-WH) in terms of finite difference operators. We relate the damped oscillator hamiltonian to the q-WH algebra and to the squeezing generator of coherent states theory. We also show that the q-WH algebra i

Alfredo Iorio, Giuseppe Vitiello

We discuss the $q$ deformation of Weyl-Heisenberg algebra in connection with the von Neumann theorem in Quantum Mechanics. We show that the $q$-deformation parameter labels the Weyl systems in Quantum Mechanics and the unitarily inequivalent representations of the canonical commutation relations in Quantum Field Theory.

Sami I. Muslih

The canonical method of constrained system is discussed. The equations of motion for a free relativistic spinning particle are obtained without using gauge fixing conditions. The quantization of this model is discussed.

Joel David Hamkins

In this paper, following an idea of Christophe Chalons, I propose a new kind of forcing axiom, the Maximality Principle, which asserts that any sentence phi holding in some forcing extension V^P and all subsequent extensions V^P*Q holds already in V. It follows, in fact, that such sentences must also hold in all forcing extensions of V. In modal terms, there

Yang Chen, Nigel Lawrence

In this paper we investigate the smallest eigenvalue, denoted as $\la_N,$ of a $(N+1)\times (N+1)$ Hankel or moments matrix, associated with the weight, $w(x)=\exp(-x^{\bt}),x>0,\bt>0$, in the large $N$ limit. Using a previous result, the asymptotics for the polynomials, $P_n(z),z\notin[0,\infty)$, orthonormal with respect to $w,$ which are required in the d

Markus Keel, Hart Smith, Christopher Sogge

We establish global existence in 3+1 dimensions of small-amplitude solutions of quasilinear Dirichlet-wave equations satisfying the null condition outside of star-shapped obstacles.

B. Enriquez

To any field K of characteristic 0, we associate a set Sha(K). Elements of Sha(K) are equivalence classes of families of Lie polynomials subject to associativity relations. We construct an injection and a retraction between Sha(K) and the set of quantization functors of Lie bialgebras over K. This construction involves the following steps. 1) To each element

P. A. Grassi, G. Policastro, M. Porrati

The quantization of the Brink-Schwarz-Casalbuoni superparticle is performed in an explicitly covariant way using the antibracket formalism. Since an infinite number of ghost fields are required, within a suitable off-shell twistor-like formalism, we are able to fix the gauge of each ghost sector without modifying the physical content of the theory. The compu

A. A. Bytsenko, F. L. Williams

We present a brief introduction to the Berline-Vergne localization formula which expresses the integral of an equivariant cohomology class as a sum over zeros of a vector field to which that class is related.

John Madore, Stefan Schraml, Peter Schupp, Julius Wess

There is an interesting dichotomy between a space-time metric considered as external field in a flat background and the same considered as an intrinsic part of the geometry of space-time. We shall describe and compare two other external fields which can be absorbed into an appropriate redefinition of the geometry, this time a noncommutative one. We shall als

Andrea Cappelli, Lachezar S. Georgiev, Ivan T. Todorov

The Z_k-parafermion Hall state is an incompressible fluid of k-electron clusters generalizing the Pfaffian state of paired electrons. Extending our earlier analysis of the Pfaffian, we introduce two ``parent'' abelian Hall states which reduce to the parafermion state by projecting out some neutral degrees of freedom. The first abelian state is a gene

D. V. Fursaev

One of explanations of the black hole entropy implies that gravity is entirely induced by quantum effects. By using arguments based on the AdS/CFT correspondence we give induced gravity interpretation of the gravity in a brane world in higher dimensional anti-de Sitter (AdS) space. The underlying quantum theory is SU(N) theory where $N$ is related to the CFT

M. G. Albrow, A. Rostovtsev

If the Higgs is produced with a large enough cross section in the {\em exclusive} reaction $p + \bar{p} \to p + H + \bar{p}$ it will give rise to a peak at $M_H$ in the {\em missing mass} ($MM$) spectrum, calculated from the 4-momenta of the beam particles and the outgoing $p$ and $\bar{p}$. The resolution in $MM$ can be approximately 250 MeV, independent of

S. Nussinov

We suggest a new correlation in diffractive production of 2 ``clusters'' $A+B\to A^\ast B^\ast$ with large intrinsic angular momenta for each $A^\ast$ and $B^\ast$ cluster. These correlations are expected in the context of the ``color dipole picture'' for high energy collision and reflect the approximate conservation of dipole direction durin

R. M. Woloshyn

The results of a recent quenched lattice QCD simulation for charmed baryons are presented. In contrast to a previous calculation, it is found that hyperfine splittings are in agreement with quark model expectations and comparable to experimental values. Preliminary calculations using lattice NRQCD yield results which are compatible with those obtained using

Enrico Nardi

Spontaneously broken Abelian gauge symmetries can explain the fermion mass hierarchies of the minimal supersymmetric standard model. In most cases it is assumed that the $U(1)_H$ symmetry is anomalous. However, non-anomalous models are also viable and yield an interesting phenomenology. Cancellation of the gauge anomalies implies the following results: unifi

M. Beneke

I review the meaning of ``QCD factorization'' in hadronic two-body B decays and then discuss recent results of theoretical (rather than phenomenological) nature: the proof of factorization at two loops; the identification of ``chirally enhanced'' power corrections; and the role of annihilation contributions.

Fritz W. Bopp, Johannes Ranft

Comparing proposed quantities to analyze charged particle fluctuations in heavy ion experiments we find the dispersion of the charges in a central rapidity box as best suited. Various energies and different nuclear sizes were considered in an explicit Dual-Parton-Model calculation using the DPMJET code. A definite deviation from predictions of recently consi

S. Godfrey, P. Kalyniak, B. Kamal, M. A. Doncheski

We report on studies of the sensitivity to extra gauge bosons of the reactions e^+ e^- -> nu nubar gamma and e gamma -> nu q + X to extract discovery limits for W' 's. The discovery potential for a W' is, for some models, comparable to that of the LHC. These processes may be also useful for determining W' and Z' couplings to fermions whic

A. A. Penin

In this talk I briefly review the recent progress in calculation of the high order corrections to the parameters of the nonrelativistic heavy quark-antiquark system in the effective theory approach.

Patrik Eden

Evolution equations for multiplicities in QCD cascades can, both in the parton and dipole picture, be used to estimate corrections beyond the formal accuracy of the modified leading log approximation (MLLA). The differences between the two pictures, and other uncertainties beyond first order MLLA corrections, are here investigated in some detail. For example

Marco Fabbrichesi

I discuss the estimate of the CP-violating ratio eps'/eps by stressing the role played by the chiral quark model in predicting the experiment and in showing that the same dynamical mechanism at work in the Delta I=1/2 rule also explains the larger value obtained for eps'/eps in this model with respect to other estimates.

J. I. Illana, M. Jack, T. Riemann

We discuss predictions for the lepton-flavour changing decays Z --> e mu, mu tau, e tau which may be searched for at the Giga-Z option of the Tesla Linear Collider project with Z resonance production rates as high as 10^9. We try to be as model-independent as possible and consider both the Dirac and Majorana mass cases. The Standard Model, if being minimally

C. Peters, B. Elliott, S. Yu, S. Eylon

A 3.2 MeV injector has been designed and built for the Darht II Project at Los Alamos Lab. The installation of the complete injector system is nearing completion at this time. The requirements for the injector are to produce a 3.2 MeV, 2000 ampere electron pulse with a flattop width of at least 2-microseconds and emittance of less than 0.15 p cm-rad normaliz

A. Bodek, U. K. Yang, T. Adams, A. Alton

We report on the extraction of the structure functions F_2 and Delta xF_3 = xF_3nu-xF_3nub from CCFR neutrino-Fe and antineutrino-Fe differential cross sections. The extraction is performed in a physics model independent (PMI) way. This first measurement for Delta xF_3, which is useful in testing models of heavy charm production, is higher than current theor

C. Peters, S. Yu, S. Eylon, W. Ghiorso

A 3.2 MeV injector has been designed and built for the Darht II Project at Los Alamos Lab. The installation of the complete injector system is nearing completion at this time. The requirements for the injector are to produce a 3.2 MeV, 2000 ampere electron pulse with a flattop width of at least 2-microseconds and emittance of less than 0.15 p cm-rad normaliz

Massimo Giovannini

The interplay between different ground based detectors and stochastic backgrounds of relic GW is described. A simultaneous detection of GW in the kHz and in the MHz--GHz region can point towards a cosmological nature of the signal. The sensitivity of a pair of VIRGO detectors to string cosmological models is presented. The implications of microwave cavities

David R. Finkelstein, Andrei A. Galiautdinov, James E. Baugh

Unimodular relativity is a theory of gravity and space-time with a fixed absolute space-time volume element, the modulus, which we suppose is proportional to the number of microscopic modules in that volume element. In general relativity an arbitrary fixed measure can be imposed as a gauge condition, while in unimodular relativity it is determined by the eve

M. Gasperini

This paper summarizes the contribution presented at the {\sl IX Marcel Grossmann Meeting} (Rome, July 2000). It is stressed, in particular, that a non-relativistic background of ultra-light dilatons, produced in the context of string cosmology, could represent today a significant fraction of cold dark matter. If the dilaton mass lies within the resonant band

M. Alves, V. B. Bezerra

We discuss the two-dimensional dilaton gravity with a scalar field as the source matter. The coupling between the gravity and the scalar, massless, field is presented in an unusual form. We work out two examples of these couplings and solutions with black-hole behaviour are discussed and compared with those found in the literature.

Roberto Mignani, Roberto Scipioni

In the Tucker-Wang approach to Metric Affine gravity we review some particular solutions of the Cartan equation for the non-riemannian part of the connection. As application we show how a quite general non Riemannian model gives a Proca type equation for the trace of the nonmetricity 1-forms Q.

Waseem Kamleh

A signature changing spacetime is one where an initially Riemannian manifold with Euclidean signature evolves into the Lorentzian universe we see today. This concept is motivated by problems in causality implied by the isotropy and homogeneity of the universe. As initially time and space are indistinguishable in signature change, these problems are removed.

Alex Brodsky, Stephane Durocher, Ellen Gethner

Scheinerman and Wilf (1994) assert that `an important open problem in the study of graph embeddings is to determine the rectilinear crossing number of the complete graph K_n.' A rectilinear drawing of K_n is an arrangement of n vertices in the plane, every pair of which is connected by an edge that is a line segment. We assume that no three vertices are

Yair Even-Zohar, Dan Roth

The eventual goal of a language model is to accurately predict the value of a missing word given its context. We present an approach to word prediction that is based on learning a representation for each word as a function of words and linguistics predicates in its context. This approach raises a few new questions that we address. First, in order to learn go

Jürgen König, Hsiu-Hau Lin, Allan H. MacDonald

We reply to the comment cond-mat/0008098 by Yang, Sun, and Chang on our paper "Theory of Diluted Magnetic Semiconductor Ferromagnetism", Phys. Rev. Lett. 84, 5628 (2000).

Qijin Chen, K. Levin, Ioan Kosztin

In this paper we demonstrate how, using a natural generalization of BCS theory, superconducting phase coherence manifests itself in phase insensitive measurements, when there is a smooth evolution of the excitation gap Δfrom above to below Tc. In this context, we address the underdoped cuprates. Our premise is that just as Fermi liquid theory is failing abov

Qing Hou, Nigel Goldenfeld, Alan McKane

We develop renormalization group methods for solving partial and stochastic differential equations on coarse meshes. Renormalization group transformations are used to calculate the precise effect of small scale dynamics on the dynamics at the mesh size. The fixed point of these transformations yields a perfect operator: an exact representation of physical ob

Dirk Helbing, Illes Farkas, Tamas Vicsek

One of the most disastrous forms of collective human behaviour is the kind of crowd stampede induced by panic, often leading to fatalities as people are crushed or trampled. Sometimes this behaviour is triggered in life-threatening situations such as fires in crowded buildings; at other times, stampedes can arise from the rush for seats or seemingly without

M. Feldbacher, F. F. Assaad

The calculation of imaginary time displaced correlation functions with the auxiliary field projector quantum Monte-Carlo algorithm provides valuable insight (such as spin and charge gaps) in the model under consideration. One of the authors and M. Imada [F.F. Assaad and M. Imada, J. Phys. Soc. Jpn. 65 189 (1996).] have proposed a numerically stable method to

Georg Goeppert, Hermann Grabert

Quantum fluctuations of the charge in the single electron box are investigated. Based on a diagrammatic expansion we calculate the average island charge number and the effective charging energy in third order in the tunneling conductance. Near the degeneracy point where the energy of two charge states coincides, the perturbative approach fails, and we explic

Markus Buttiker

The charge fluctuations of two nearby mesoscopic conductors coupled only via the long range Coulomb force are discussed and used to find the dephasing rate which one conductor exerts on the other. The discussion is based on a formulation of the scattering approach for charge densities and the density response to a fluctuating potential. Coupling to the Poiss

E. M. González, Y. Lin, E. E. Mendez

We have measured the zero-bias differential tunneling conductance of InAs/AlSb/GaS b/AlSb/InAs heterostructures at low temperatures (1.7K < T < 60K) and unde r a magnetic field at various angles with the heterostructure&#39;s interfaces. Shubni kov-de Haas oscillations in the magnetoconductance reveal the two-dimensional (2D) character of the electrons accum

S. Foulon, F. Brosens, J. T. Devreese, L. F. Lemmens

For a fermion gas with equally spaced energy levels that is subjected to a magnetic field, the particle density is calculated. The derivation is based on the path integral approach for identical particles, in combination with the inversion techniques for the generating function of the static response functions. Explicit results are presented for the ground s

Tibor Antal, Michel Droz

A coarse grained description of a two-dimensional prey-predator system is given in terms of a 3-state lattice model containing two control parameters: the spreading rates of preys and predators. The properties of the model are investigated by dynamical mean-field approximations and extensive numerical simulations. It is shown that the stationary state phase

G. Caldarelli, M. Piccioni, E. Sciubba

In this paper we test computationally the performance of CAPM in an evolutionary setting. In particular we study the stability of wealth distribution in a financial market where some traders invest as prescribed by CAPM and others behave according to different portfolio rules. Our study is motivated by recent analytical results that show that, whenever a log

R. van Gastel, E. Somfai, S. B. van Albada, W. van Saarloos

We report scanning tunneling microscopy observations, which imply that all atoms in a close-packed copper surface move frequently, even at room temperature. Using a low density of embedded indium `tracer&#39; atoms, we visualize the diffusive motion of surface atoms. Surprisingly, the indium atoms seem to make concerted, long jumps. Responsible for this moti

A. L. Vazquez de Parga, F. J. Garcia-Vidal, R. Miranda

Co islands grown on Cu(111) with a stacking fault at the interface present a conductance in the empty electronic states larger than the Co islands that follow the stacking sequence of the Cu substrate. Electrons can be more easily injected into these faulted interfaces, providing a way to enhance transmission in future spintronic devices. The electronic stat

Alexander Schindler, Reinhard Koenig, Thomas Herrmannsdoerfer, Hans. F. Braun

Compacted platinum powders exhibit a sharp onset of diamagnetic screening at $T \simeq 1.9$ mK in zero magnetic field in all samples investigated. This sharp onset is interpreted in terms of the intragranular transition into the superconducting state. At lower temperatures, the magnetic ac susceptibility strongly depends on the ac field amplitude and reflect

Z. B. Huang, H. Q. Lin, J. E. Gubernatis

Using the Constrained Path Monte Carlo (CPMC) method, we simulated the two-dimensional, three-band Hubbard model to study pairing, charge, and spin correlations as a function of electron and hole doping and the Coulomb repulsion $V_{pd}$ between charges on neighboring Cu and O lattice sites. As a function of distance, both the $d_{x^2 - y^2}$-wave and extend

J. Tejada, E. M. Chudnovsky, E. del Barco, J. M. Hernandez

We propose two potential realisations for quantum bits based on nanometre scale magnetic particles of large spin S and high anisotropy molecular clusters. In case (1) the bit-value basis states |0> and |1> are the ground and first excited spin states Sz = S and S-1, separated by an energy gap given by the ferromagnetic resonance (FMR) frequency. In case (2),

G. Mohler, D. Stroud

For a clean high-T$_c$ superconductor, we analyze the Lawrence-Doniach free energy in a tilted magnetic field within the lowest Landau level (LLL) approximation. The free energy maps onto that of a strictly $c$-axis field, but with a reduced interlayer coupling. We use this result to calculate the tilt modulus $C_{44}$ of a vortex lattice and vortex liquid.

Alan D. Sokal

I review recent results and unsolved problems concerning the hard-core lattice gas and the q-coloring model (antiferromagnetic Potts model at zero temperature). For each model, I consider its equilibrium properties (uniqueness/nonuniqueness of the infinite-volume Gibbs measure, complex zeros of the partition function) and the dynamics of local and nonlocal M

A. Brunthaler, H. Falcke, G. C. Bower, M. F. Aller

So far, all relativistically boosted jets with superluminal motion have only been detected in typical radio galaxies with early type host galaxies. We have now discovered superluminal motion in the Seyfert I galaxy III Zw 2, classified as a spiral. The lower limit for the apparent expansion speed is 1.25 c. Spectral and spatial evolution are closely linked.

Craig J. Copi, Lawrence M. Krauss

Angular Sensitivity can provide a key additional tool which might allow unambiguous separation of a signal due to Galactic halo WIMPs from other possible backgrounds in direct detectors. We provide a formalism which allows a calculation of the expected angular distribution of events in terrestrial detectors with angular sensitivity for any incident distribut

Michael Blanton, Pasquale Blasi, Angela V. Olinto

We calculate numerically the spectrum of ultra-high energy cosmic rays on Earth assuming that their sources are distributed in space like the observed galaxies. We use the CfA2 and the PSCz galaxy redshift surveys to model the local galaxy distribution, properly taking into account the galaxy selection functions for each survey. When the survey selection eff

P. L. Gomez, C. Loken, K. Roettiger, J. O. Burns

We report the results of recent numerical simulations of the head-on merger of a cooling flow cluster with an infalling subcluster of galaxies. These simulations examined the effects of different types of cluster mergers (with 16:1 and 4:1 mass ratios) on the evolution of cluster cooling flows (mass accretion rates of 100 and 400 M/year. The 2-dimensional si

E. Pedretti, A. Labeyrie, L. Arnold, N. Thureau

We show star images obtained with a miniature ``densified pupil imaging interferometer&#39;&#39; also called a hyper-telescope. The formation of such images violates a ``golden rule of imaging interferometers&#39;&#39; which appeared to forbid the use of interferometric arrangements differing from a Fizeau interferometer. These produce useless images when th

N. Aghanim, O. Forni, F. R. Bouchet

A very important property of a statistical distribution is to know whether it obeys Gaussian statistics or not. On the one hand, it is of paramount importance in the context of CMB anisotropy studies, since deviations from a Gaussian distribution could indicate the presence of uncorrected measurement systematics, of remaining fluctuations contributed by fore

Andy Shearer, Aaron Golden

We show that observations of pulsars with pulsed optical emission indicate that the peak flux scales according to the magnetic field strength at the light cylinder. The derived relationships indicate that the emission mechanism is common across all of the observed pulsars with periods ranging from 33ms to 385 ms and ages of 1000-300,000 years. It is noted th

Tsutomu T. Takeuchi, Takako T. Ishii, Hiroyuki Hirashita, Kohji Yoshikawa

Recently reported infrared (IR) galaxy number counts and cosmic infrared background (CIRB) all suggest that galaxies have experienced a strong evolution sometime in their lifetime. We statistically estimate the galaxy evolution history from these data. We find that an order of magnitude increase of the far-infrared (FIR) luminosity at redshift z = 0.5 - 1.0

Takashi Hamana, Stephane Colombi, Yannick Mellier

We study cosmic shear statistics using the ray-tracing simulation combined with a set of large $N$-body simulations. In this contribution, we first describe our method. Then we show some selected results especially focusing on effects of the deflection of light rays and the lens-lens coupling which are neglected in making the theoretical predictions of the c

U. Kolb, A. R. King, I. Baraffe

Using stellar models we investigate the relation between mass and the spectral type of the secondary star in low-mass short-period compact binaries such as cataclysmic variables and soft X-ray transients. Allowing for different mass transfer rates and different system ages prior to mass transfer we find that the secondaries should populate a band in the spec

Heino Falcke, Joseph Lehar, Richard Barvainis, Neil M. Nagar

We report on two surveys of radio-weak AGN to look for radio variability. We find significant variability with an RMS of 10-20% on a timescale of months in radio-quiet and radio-intermediate quasars. This exceeds the variability of radio cores in radio-loud quasars (excluding blazars), which vary only on a few percent level. The variability in radio-quiet qu

D. Schertl, Y. Balega, T. Hannemann, K. -H. Hofmann

We present bispectrum speckle interferometry and speckle polarimetry of the deeply embedded infrared bipolar outflow source S140 IRS1, a massive protostellar object in the L1204 molecular cloud. Using the SAO 6 m telescope, we obtained 280 mas resolution polarization maps of S140 IRS1 as well as a K-band image with diffraction-limited resolution lambda/D of

Rainer Beck

The radio emission from M31 (like HI, CO, FIR and Hα) is concentrated in the &#39;10 kpc ring&#39;, giving an impressive example that cosmic rays are produced in star-forming regions. M31 and M33 have similar strengths of the total magnetic field, but very different field structures: The field structure in M31 is exceptionally regular while that in M33 is ra

H. Mouri, Y. Taniguchi

Old starburst galaxies are deficient in O stars, and hence do not exhibit strong line emission in the optical regime. However, there remain many B stars, which are expected to heat dust grains and generate strong continuum emission in the far-infrared. The IRAS data for a statistically complete sample of nearby galaxies reveal for the first time that such ob

Katsuaki Asano, Takeshi Fukuyama

Using idealized models of the accretion disk we investigate the relativistic effects on the energy deposition rate via neutrino pair annihilation near the rotation axis of a Kerr black hole. Neutrinos are emitted from the accretion disk. The bending of neutrino trajectories and the redshift due to the disk rotation and gravitation are taken into consideratio

J. F. Zhou, X. Y. Hong, D. R. Jiang, T. Venturi

The two 5GHz VLBI (Very Long Baseline Interferometry) observations (1996 June and 1997 November) presented in this paper, combined with several formerb VLBI observations at 8.4GHz and 5GHz, suggest that the radio flares of the blazar PKS 0420$-$014 can be divided into two classes according to their geometric origins in 5 or 8.4GHz VLBI maps and the propertie

Draza Markovic

Recent discovery of kilohertz quasi-periodic brightness oscillations of low mass X-ray binaries (LMXBs) has attracted attention to highly relativistic periodic motion near accreting neutron stars. Most models proposed so far involve (almost) inertial motion in the vicinity of the stars&#39; innermost stable circular orbits. In the present paper we study gene

Todd A. Thompson, Adam Burrows

In preparation for a set of hydrodynamical simulations of core-collapse supernovae and protoneutron star winds, we investigate the rates of production and thermalization of $ν_μ$ and $ν_τ$ neutrinos in dense nuclear matter. Included are contributions from electron scattering, electron-positron annihilation, nucleon-nucleon bremsstrahlung, and nucleon scatter

Gennaro Corcella

We show some recent HERWIG results related to the top quark mass measurement at the LHC and discuss possible improvements for studies of the bottom quark fragmentation function in the top decay.

E. Eyras, S. Panda

We analyse the spectrum of non-BPS branes in the type I theory on the orbifold $T^4/{\cal I}_4$. We present a detailed analysis of the action of the worldsheet parity $\Omega$ on the different D-brane boundary state sectors of type IIB on $T^4/{\cal I}_4$, using the covariant formulation. Using these results we derive the spectrum of branes in the type I orb

Luis A. Anchordoqui, Thomas P. McCauley, Stephen Reucroft, John Swain

In this article we examine the question of whether the highest energy cosmic ray primaries could be ultra relativistic magnetic monopoles. The analysis is performed within the framework of large compact dimensions and TeV scale quantum gravity. Our study indicates that while this hypothesis must be regarded as highly speculative it cannot be ruled out with p

Sabine Jeschonnek

In the literature, one often finds calculations of (e,e&#39;p) reactions at GeV energies using the factorization approach. Factorization implies that the differential cross section can be written as the product of an off-shell electron-proton cross section and a distorted missing momentum distribution. While this factorization appears in the non-relativistic

Boris E. Stern, Yana Tikhomirova, Dmitrii Kompaneets, Roland Svensson

During a scan of the archival BATSE daily records covering the entire 9.1 years (TJD 8369-11690) of the BATSE operation, 3906 gamma-ray bursts (GRBs) have been detected. 2068 of these GRBs are previously known BATSE triggers while 1838 of them are new non-triggered bursts. It is important that all events were detected in the same type of data and were proces

Philip Candelas, Duiliu-Emanuel Diaconescu, Bogdan Florea, David R. Morrison

We study new nonperturbative phenomena in N=1 heterotic string vacua corresponding to pointlike bundle singularities in codimension three. These degenerations result in new four-dimensional infrared physics characterized by light solitonic states whose origin is explained in the dual F-theory model. We also show that such phenomena appear generically in $E_7

Ben J Baten

This report provides an alternative to the Standard Model of particle physics. The model described here is based on results from Quantum Field Mechanics, according to which all fundamental particles and interactions originate from the interaction of two pre-space/pre-time protofields. In contrast with the Standard Model, (virtual) interaction-particles are a

Victor Belinicher, Joao da Providencia

We have developed a consistent theory of the Heisenberg quantum antiferromagnet in the disordered phase with a short range antiferromagnetic order on the basis of the path integral for spin coherent states. We have presented the Lagrangian of the theory in a form which is explicitly invariant under rotations and found natural variables in terms of which one

Adan Garriga, Felix Ritort

In order to describe the thermodynamics of the glassy systems it has been recently introduced an extra parameter also called effective temperature which generalizes the fluctuation-dissipation theorem (FDT) to systems off-equilibrium and supposedly describes thermal fluctuations around the aging state. Here we investigate the applicability of a zero-th law f

A. A. Tseytlin

We discuss light-cone gauge description of type IIB Green-Schwarz superstring in AdS_5 x S^5 with a hope to make progress towards understanding spectrum of this theory. As in flat space, fixing light cone gauge consists of two steps: (i) fixing kappa symmetry in such a way that the fermionic part of the action does not depend on x^-; (ii) fixing 2-d reparame

R. A. Bertlmann, E. Kohlprath

We evaluate the gravitational Schwinger terms for the specific two-dimensional model of Weyl fermions in a gravitational background field using a technique introduced by Kallen and find a relation which connects the Schwinger terms with the linearized gravitational anomalies.

J. Schiøtz, T. Leffers, B. N. Singh

Recently, a dislocation free deformation mechanism was proposed by Kiritani et al., based on a series of experiments where thin foils of fcc metals were deformed at very high strain rates. In the experimental study, they observed a large density of stacking fault tetrahedra, but very low dislocation densities in the foils after deformation. This was interpre

T. E. O. Ericson, B. Loiseau, A. W. Thomas

We critically evaluate the isovector GMO sum rule for forward pion-nucleon scattering using the recent precision measurements of negatively charged pion-proton and pion-deuteron scattering lengths from pionic atoms. We deduce the charged-pion-nucleon coupling constant, with careful attention to systematic and statistical uncertainties. This determination giv

A. Tsvetkov, J. Kvasil, R. G. Nazmitdinov

The cranked Skyrme III effective Hamiltonian is applied for the analysis of the rotational dependence of the quadrupole and octupole moments in Ra, Th, and U isotopes. A comparison of the intrinsic electric dipole moments calculated in the model with available experimental and theoretical values is presented. It is found that the non-axial octupole deformati

P. Desgrolard, A. Lengyel, E. Martynov

The drastic rise of the proton structure function F_2(x,Q^2) when the Björken variable x decreases, seen at HERA for a large span of Q^2, negative values for the 4-momentum transfer, may be damped when Q^2 increases beyond several hundreds GeV^2. A new data analysis and a comparison with recent models for the proton structure function is proposed to discuss

Bodo Geyer, Petr M. Lavrov, Pavel Yu. Moshin

We apply the modified triplectic formalism for quantizing several popular gauge models - non-abelian antisymmetric tensor field model, W2-gravity and two-dimensional gravity with dynamical torsion. The explicit solutions are obtained for the generating equations of the quantum action and the gauge-fixing functional. Using these solutions we construct the vac

Komajiro Niizeki, Nobuhisa Fujita

One-dimensional quasilattices are classified into mutual local-derivability (MLD) classes on the basis of geometrical and number-theoretical considerations. Most quasilattices are ternary, and there exist an infinite number of MLD classes. Every MLD class has a finite number of quasilattices with inflation symmetries. We can choose one of them as the represe

Markus Lazar

We introduce chiral-even and chiral-odd meson wave functions as vacuum-to-meson matrix elements of bilocal quark operators with well-defined (geometric) twist. Thereby, we achieve a Lorentz invariant classification of these distributions which differ from the conventional ones by explicitly taking into account the trace terms. The relations between conventio

Atsuo Satou, Masanori Yamanaka

We numerically study energy spectra and localization properties of the double exchange model at irrational filling factor. To obtain variational ground state, we use a mumerical technique in momentum space by ``embedded&#39;&#39; boundary condition which has no finite size effect a priori. Although the Hamiltonian has translation invariance, the ground state

Bodo Geyer, Markus Lazar

We introduce the chiral-even and chiral-odd quark distributions as forward matrix elements of related bilocal quark operators with well-defined (geometric) twist. Thereby, we achieve a Lorentz invariant classification of these distributions which differ from the conventional ones by explicitly taking into account the necessary trace terms. The relations betw