arXiv papers from April 2000

T. H. Jarrett, T. Chester, R. Cutri, S. Schneider

The Two Micron All Sky Survey (2MASS) is now underway and will provide a complete census of galaxies as faint as 13.5 mag (3 mJy) at 2.2 microns for most of the sky, and ~12.1 mag (10 mJy) for regions veiled by the Milky Way. This census has already discovered nearby galaxies previously hidden behind our Galaxy, and will allow delineation of large-scale stru

Mark Lacy

Radio galaxies are uniquely useful as probes of large-scale structure as their uniform identification with giant elliptical galaxies out to high redshift means that the evolution of their bias factor can be predicted. As the initial stage in a project to study large-scale structure with radio galaxies we have performed a small redshift survey, selecting 29 r

M. Grigorescu

The collective dynamics of a many-body system is described as a special case of low-energy quantum dynamics, occurring when the ground state breaks a continuous symmetry of the Hamiltonian. This approach is applied to the spontaneous breaking of the rotational symmetry of a nuclear Hamiltonian. It is shown that the excitation operator of the isovector low-ly

Sumit R. Das, Banhiman Ghosh

A class of supergravity backgrounds have been proposed as dual descriptions of strong coupling large-N noncommutative Yang-Mills (NCYM) theories in 3+1 dimensions. However calculations of correlation functions in supergravity from an evaluation of relevant classical actions appear ambiguous. We propose a resolution of this ambiguity. Assuming that {\it some}

A. M. N. Ferguson, J. S. Gallagher, R. F. G. Wyse

Lying at a projected distance of 40' or 9 kpc from the centre of M31, Andromeda IV is an enigmatic object first discovered during van den Bergh's search for dwarf spheroidal companions to M31. Being bluer, more compact and higher surface brightness than other known dwarf spheroidals, it has been suggested that And IV is either a relatively old `star cloud' i

Jaime E. Santos, Erwin Frey, Franz Schwabl

We consider a simple model for a superlattice composed of a thin magnetic film placed between two bulk superconductors. The magnetic film is modelled by a planar but otherwise arbitrary distribution of magnetic dipoles and the superconductors are treated in the London approximation. Due to the linearity of the problem, we are able to compute the magnetic ene

Keshav Dasgupta, Sunil Mukhi, Govindan Rajesh

When unstable Dp-branes in type II string theory are placed in a B-field, the resulting tachyonic world-volume theory becomes noncommutative. We argue that for large noncommutativity parameter, condensation of the tachyon as a noncommutative soliton leads to new decay modes of the Dp-brane into (p-2)-brane configurations, which we interpret as suitably smear

Ayan Guha, A. K. Raychaudhuri, A. R. Raju, C. N. R. Rao

Non-linear conduction in a single crystal of charge-ordered Pr$_{0.63}$Ca$_{0.37}$MnO$_{3}$ has been investigated in an applied magnetic field. In zero field, the non-linear conduction, which starts at T$<$T$_{CO}$ can give rise to a region of negative differential resistance (NDR) which shows up below the N\'eel temperature. Application of a magnetic field

Branislav Jurco, Peter Schupp, Julius Wess

A noncommutative gauge theory is associated to every Abelian gauge theory on a Poisson manifold. The semi-classical and full quantum version of the map from the ordinary gauge theory to the noncommutative gauge theory (Seiberg-Witten map) is given explicitly to all orders for any Poisson manifold in the Abelian case. In the quantum case the construction is b

ZhengWei Zhou, GuangCan Guo

In this paper we summarize the necessary condition for incomparable states which can be catalyzed under entanglement-assisted LQCC (ELQCC). When we apply an extended condition for entanglement transformation to entanglement-assisted local manipulation we obtain a fundamental limit for entanglement catalysts. Some relative questions are also discussed.

A. Bueno, M. Campanelli, A. Rubbia

In order to fully address the oscillation processes at a neutrino factory, a detector should be capable of identifying and measuring all three charged lepton flavors produced in charged current interactions {\it and} of measuring their charges to discriminate the incoming neutrino helicity. This is an experimentally challenging task, given the required detec

Johannes Ruoff, Pablo Laguna, Jorge Pullin

The excitation of neutron stars is expected to be an important source of gravitational radiation. Of fundamental importance is then to investigate mechanisms that trigger oscillations in neutron stars in order to characterize the emitted radiation. We present results from a numerical study of the even-parity gravitational radiation generated from a particle

Ll. Bel

A general theory of frames of reference proposed in a preceding publication is considered here in the framework of the post-Newtonian approximation, assuming that the frame of reference is centered on a time-like geodesic. The problem of taking into account the rotation of the frame of reference, which is usually ignored or incorrectly oversimplified, is her

Du Dongsheng, Yang Deshan, Zhu Guohuai

In this work, we calculate the branching ratios and CP asymmetries of the decays of $B \to \pi \pi$ and $\pi K$ in the frame of QCD factorization in the heavy quark limit. We also compare the results with the estimates by using conventional factorization and experimental measurements.

Yu. S. Barash, M. S. Kalenkov, J. Kurkijarvi

We report a theoretical study on the deviations of the Meissner penetration depth $\lambda(T)$ from its London value in d-wave superconductors at low temperatures. The difference arises from low-energy surface Andreev bound states. The temperature dependent penetration depth is shown to go through a minimum at the temperature $T_{m0}\sim \sqrt{\xi_0/\lambda_

L. Santos, G. V. Shlyapnikov, P. Zoller, M. Lewenstein

We discuss Bose-Einstein condensation in a trapped gas of bosonic particles interacting dominantly via dipole-dipole forces. We find that in this case the mean-field interparticle interaction and, hence, the stability diagram are governed by the trapping geometry. Possible physical realisations include ultracold heteronuclear molecules, or atoms with laser i

Kazimir Y. Kolossovski, Alexander V. Buryak, Victoria V. Steblina, Rowland A. Sammut

We demonstrate that weak parametric interaction of a fundamental beam with its third harmonic field in Kerr media gives rise to a rich variety of families of non-fundamental (multi-humped) solitary waves. Making a comprehensive comparison between bifurcation phenomena for these families in bulk media and planar waveguides, we discover two novel types of soli

Amnon Yekutieli

Let A be a finite dimensional algebra over an algebraically closed field K. The derived Picard group DPic(A) is the group of two-sided tilting complexes over A modulo isomorphism. We prove that DPic(A) is a locally algebraic group, and its identity component is Out^0(A). If B is a derived Morita equivalent algebra then DPic(A) is isomorphic to DPic(B) as loc

M. A. M. Gomes, R. R. Landim, C. A. S. Almeida

By dimensional reduction of a massive supersymmetric B$\wedge $F theory, a manifestly N=1 supersymmetric completion of a massive antisymmetric tensor gauge theory is constructed in (2+1) dimensions. In the N=1-D=3 superspace, a new topological term is used to give mass for the Kalb-Ramond field. We have introduced a massive gauge invariant model using the St

Liwen Qian, G. W. Wei

Error estimation is given for a regularized Shannon's sampling formulae, which was found to be accurate and robust for numerically solving partial differential equations.

X. Guardiola, A. Diaz-Guilera, M. Llas, C. J. Perez

We study synchronization dynamics of a population of pulse-coupled oscillators. In particular, we focus our attention in the interplay between networks topological disorder and its synchronization features. Firstly, we analyze synchronization time $T$ in random networks, and find a scaling law which relates $T$ to networks connectivity. Then, we carry on com

Biswajoy Brahmachari

We discuss how predictions of Fritzsch textures can be consistent with values of fermion masses and mixing angles if we embed them in a supersymmetric grand unified theory.

M. V. Simkin, G. D. Mahan

The mean free path of phonons in superlattices is estimated. It is shown to be strongly dependent on the superlattice period due to the Umklapp scattering in subbands. It first falls with increasing the superlattice period until it becomes comparable with the latter after what it rises back to the bulk value. Similar behavior is expected of heat conductivity

J. T. Devreese

A conduction electron (or hole) together with its self-induced polarisation in a polar semiconductor or an ionic crystal forms a quasi-particle, which is called a polaron. The polaron concept is of interest, not only because it describes the particular physical properties of charge carriers in polarizable solids but also because it constitutes an interesting

J. M. Shull, J. Tumlinson, E. B. Jenkins, H. W. Moos

We describe a moderate-resolution FUSE mini-survey of H2 in the Milky Way and Magellanic Clouds, using four hot stars and four AGN as background sources. FUSE spectra of nearly every stellar and extragalactic source exhibit numerous absorption lines from the H2 Lyman and Werner bands between 912 and 1120 A. One extragalactic sightline, PKS 2155-304, with low

K. R. Sembach, B. D. Savage, J. M. Shull, E. B. Jenkins

We have used moderate-resolution (FWHM ~ 25 km/sec) spectra of AGNs and QSOs observed by the Far Ultraviolet Spectroscopic Explorer (FUSE) to make the first definitive measurements of absorption by hot gas in high velocity clouds (HVCs) at large distances from the Galactic plane. Seven of the 11 sight lines studied exhibit high velocity (|V(LSR)| > 100 km/se

Hilmar Forkel

The impact of QCD instantons on scalar glueball properties is studied in the framework of an instanton-improved operator product expansion (IOPE) for the 0^{++} glueball correlation function. Direct instanton contributions are found to strongly dominate over those from perturbative fluctuations and soft vacuum fields. All IOPE sum rules, including the one in

Robbert Dijkgraaf, Juan Maldacena, Gregory Moore, Erik Verlinde

We derive an exact expression for the Fourier coefficients of elliptic genera of Calabi-Yau manifolds. When applied to k-fold symmetric products of K3 surfaces the expression is well-suited to studying the AdS/CFT correspondence on AdS3 x S3. The expression also elucidates an SL(2,Z) invariant phase diagram for the D1/D5 system involving deconfining transiti

J. -P. Blaizot, E. Iancu, A. Rebhan

We propose a gauge-invariant and manifestly UV finite resummation of the physics of hard thermal/dense loops (HTL/HDL) in the thermodynamics of the quark-gluon plasma. The starting point is a simple, effectively one-loop expression for the entropy or the quark density which is derived from the fully self-consistent two-loop skeleton approximation to the free

J. A. Peacock, R. E. Smith

We propose a heuristic model that displays the main features of realistic theories for galaxy bias. We show that the low-order clustering statistics of the dark-matter distribution depend almost entirely on the locations and density profiles of dark-matter haloes. A hypothetical galaxy catalogue depends on (i) the efficiency of galaxy formation, as manifeste

M. B. Ruskai, E. Werner, S. Szarek

This paper has been superseded by quant-ph/0101003.

Thomas H. Puzia, Markus Kissler-Patig, Jean P. Brodie, Linda L. Schroder

The properties of globular clusters in dwarf galaxies are key to understanding the formation of globular cluster systems, and in particular in verifying scenarios in which globular cluster systems of larger galaxies formed (at least partly) from the accretion of dwarf galaxies. Here, we revisit the globular cluster system of the dE,N galaxy NGC 3115 DW1 - a

L. P. Chimento, F. Pennini, A. Plastino

We show that using the most parsimonious version of Frieden and Soffer's extreme information principle (EPI) with a Fisher measure constructed with escort probabilities, the concomitant solutions obey a type of Naudts' duality for nonextensive ensembles. We also determine in closed form the general (normalized) probability distribution that minimizes Fisher'

Peter W. Shor

These notes discuss the quantum algorithms we know of that can solve problems significantly faster than the corresponding classical algorithms. So far, we have only discovered a few techniques which can produce speed up versus classical algorithms. It is not clear yet whether the reason for this is that we do not have enough intuition to discover more techni

Masako Asano, Makoto Natsuume

It is well-known that the standard no-ghost theorem can be extended straightforwardly to the general c=26 CFT on R^{d-1,1} \times K, where 2 \leq d \leq 26 and K is a compact unitary CFT of appropriate central charge. We prove the no-ghost theorem for d=1, i.e., when only the timelike direction is flat. This is done using the technique of Frenkel, Garland an

Vladimir Tchernov

We show that for a large class of contact 3-manifolds the groups of Vassiliev invariants of Legendrian and of framed knots are canonically isomorphic. As a corollary, we obtain that the group of finite order Arnold's $J^+$-type invariants of wave fronts on a surface $F$ is isomorphic to the group of Vassiliev invariants of framed knots in the spherical cotan

F. M. Pen'kov

Resonance penetration of two coupled particles through a repulsive barrier is considered. It is shown that a local minimum of the total potential generates metastable bound states, and their spectrum determines the position of resonances in the penetration probability. It is pointed out that the probabilities of tunneling of two interacting particles from th

P. Lancon, G. Batrouni, L. Lobry, N. Ostrowsky

Space dependent diffusion of micrometer sized particles has been directly observed using digital video microscopy. The particles were trapped between two nearly parallel walls making their confinement position dependent. Consequently, not only did we measure a diffusion coefficient which depended on the particles' position, but also report and explain a new

Hui-fang Wu, Tao Huang

We apply the shell-model wave-functions of $^{76}Ge$ to calculate the nuclear matrix elements and the half-life of the $2\nu\beta\beta$ decay in $^{76}Ge$. Our result is comparable to the recent observed $2\nu\beta\beta$-decay half-life of $^{76}Ge$. Furthemore it provides the upper limit of the effective neutrino mass is about 0.4 eV from the recent experim

Hui-fang Wu, Jun Cao, Tao Huang

For deuteron electromagnetic form factors,perturbative QCD(pQCD) predicts that $G^{+}_{00}$ becomes the dominate helicity amplitude and that $G^{+}_{+0}$ and $G^{+}_{+-}$ are suppressed by factors $\Lambda_{\rm QCD}/Q$ and $\Lambda_{\rm QCD}^2/Q^2$ at large $Q^2$,respectively. We try to discuss the higher order corrections beyond the pQCD asymptotic predicti

Hao-Sheng Zeng, Le-Man Kuang

In this paper we propose an approach to prepare GHZ states of an arbitrary multi-particle system in terms of Grover's fast quantum searching algorithm. This approach can be regarded as an extension of the Grover's algorithm to find one or more items in an unsorted database.

Changsong Zhou, C. -H. Lai

Sensitive dependence of nonlinear systems on initial conditions or parameters can be useful in applications. We propose in this paper that bubbling behavior in simple driven symmetrical maps may be used as a working principle of sensitive devices. The system is stable when there is no input and displays bursting behavior when there is small input. The symmet

Changsong Zhou, C. -H. Lai

Synchronization of chaotic system may occur only when the largest conditional Lyapunov exponent of the driven system is negative. The synchronization with positive conditional Lyapunov reported in a recent paper (Phys. Rev. E, {\bf 56}, 2272 (1997)) is a combined result of the contracting region of the system and the finite precision in computer simulations.

Bambi Hu, Le-Man Kuang

We study tunneling dynamics of atomic pairs in Bose-Einstein condensates with Feshbach resonances. It is shown that the tunneling of the atomic pairs depends on not only the tunneling coupling between the atomic condensate and the molecular condensate, but also the inter-atomic nonlinear interactions and the initial number of atoms in these condensates. It i

C. -H. Lai, Changsong Zhou

Synchronization of identical chaotic systems subjected to common noise has been the subject of recent research. Studies on several chaotic systems have shown that, the synchronization is actually induced by the non-zero mean of the noise, and symmetric noise with zero-mean cannot lead to synchronization. Here it is presented that synchronization can be achie

Yi-Ping Qin, Guang-Zhong Xie, Sui-Jian Xue, Xue-Tang Zheng

The well-known hardness-duration correlation of gamma-ray bursts (GRBs) is investigated with the data of the 4B catalog. We find that, while the hardness ratio and the duration are obviously correlated for the entire set of the 4B catalog, they are not at all correlated for the two subsets divided at the duration of 2 seconds. However, for other subsets with

Michael Byrne

Gravitons should have momentum just as photons do; and since graviton momentum would cause compression rather than elongation of spacetime outside of matter; it does not appear that gravitons are compatible with Swartzchild's spacetime curvature. Also, since energy is proportional to mass, and mass is proportional to gravity; the energy of matter is proporti

Benjamin Grinstein, Detlef R. Nolte, Witold Skiba

A solution to the cosmological constant problem has been proposed in which our universe is a 3-brane in a 5-dimensional spacetime. With a bulk scalar, the field equations admit a Poincare invariant brane solution regardless of the value of the cosmological constant (tension) on the brane. However, the solution does not include matter in the brane. We find ne

Scott Watson

This paper is intended to offer a pedagogical treatment of cosmological modeling and inflationary cosmology. In recent years, inflation has become accepted as a standard scenario making predictions that are testable by observations of the cosmic background. It is therefore manifest that anyone wishing to pursue the study of cosmology and large-scale structur

Terence Tao

The $X^{s,b}$ spaces, as used by Beals, Bourgain, Kenig-Ponce-Vega, Klainerman-Machedon and others, are fundamental tools to study the low-regularity behaviour of non-linear dispersive equations. It is of particular interest to obtain bilinear or multilinear estimates involving these spaces. By Plancherel's theorem and duality, these estimates reduce to esti

F. Marsiglio, J. E. Hirsch

We calculate the doping dependence of the penetration depths and optical sum rule violation in La_(2-x)Sr_xCuO_4 within the model of hole superconductivity. In the clean limit the predicted in-plane sum rule violation is larger than the c-axis one, however in the presence of disorder the latter one becomes very substantially enhanced.

Dan M. Stamper-Kurn, Wolfgang Ketterle

These notes discuss two aspects of the physics of atomic Bose-Einstein condensates: optical properties and spinor condensates. The first topic includes light scattering experiments which probe the excitations of a condensate in both the free-particle and phonon regime. At higher light intensity, a new form of superradiance and phase-coherent matter wave ampl

A. M. Dyugaev, I. D. Vagner, P. Wyder

We show that scattering of the conduction electrons by nuclear spins via the hyperfine interaction may lead the upper limit on the mean free path in clean metals. Nuclear spins with s >1/2 may cause a strong dephasing in dirty limit due to the quadrupole coupling to the random potential fluctuations caused by static impurities and lattice imperfections.

J. M. Shull, M. L. Giroux, S. V. Penton, J. Tumlinson

We describe a moderate-resolution (20-25 km/s) FUSE study of the low-redshift intergalactic medium. We report on studies of 7 extragalactic sightlines and 12 Ly-beta absorbers that correspond to Ly-alpha lines detected by HST/GHRS and STIS. These absorbers appear to contain a significant fraction of the low-z baryons and were a major discovery of the HST spe

Timothy M. Brown, David Charbonneau

The STARE instrument is a small aperture, wide-field, CCD-based telescope that delivers high cadence time series photometry on roughly 40,000 stars in a typical field centered on the galactic plane. In a two-month observing run on a field, we obtain sufficient precision on roughly 4,000 stars to detect a close-in Jupiter-sized companion in an edge-on orbit.

Yi-Ping Qin, Guang-Zhong Xie, Xue-Tang Zheng, En-Wei Liang

In this letter, the old issue of whether redshifts of quasars are of cosmological origin is investigated. We make a plot of absorption redshifts versus emission redshifts for quasars with large amounts of data. Our study shows that, almost all absorption redshifts are smaller than the corresponding emission redshifts. The relation between the absorption and

A. F. Kracklauer

In a remarkably insightful pair of papers recently, Sica demonstrated that: dichotomic data taken in any experiment that violates Bell's inequalities ``cannot represent any data streams that could possibly exist or be imagined'' if it is to be consistent with the derivation of the inequalities.\cite{sica} The present writer maintains, however, that correctio

S. del Campo, N. Cruz

In a Brans-Dicke (BD) cosmological model, the energy density associated with some scalar field decreases as $\displaystyle a^{{-2}(\frac{\omega_{o}+ {\frac12}%}{\omega_{o}+1})} $ with the scale factor $a(t)$ of the Universe, giving a matter with an Equation of state $\displaystyle p=-{1/3}(\frac{2+\omega_{o}}{1+\omega_{o}}) \rho $. In this model, the Univers

C. Firmani, E. D'Onghia, G. Chincarini, X. Hernandez

One of the predictions of the standard CDM is that dark haloes have centrally divergent density profiles. An extensive body of rotation curve observations of dwarf and low surface brightness galaxies shows the dark haloes of those systems to be characterized by soft constant density central cores. Several physical processes have been proposed to produce soft

S. Sultansoy

The flavor democracy favors the existence of the nearly degenerate fourth SM family, whereas the fifth SM family is disfavored both by the mass phenomenology and precision tests of the Standard Model. The multi-hundreds GeV fourth family quarks will be copiously produced at the LHC. However, the first indication of the fourth family may come from the Higgs s

Julien Lesgourgues, Marco Peloso

The very recent Boomerang results give an estimate of unprecedented precision of the Cosmic Microwave Background anisotropies on sub--degree scales. A puzzling feature for theoretical cosmology is the low amplitude of the second acoustic peak. Through a qualitative discussion, we argue that a scarcely considered category of flat models, with a leptonic asymm

J. Andrew Green

Quark-quark and quark-lepton searches for compositenss at the Fermilab Tevatron are summarized. These are of the contact-interaction variety where sqrt(s-hat) < the hypothesized mass scales, Lambda. Tevatron experiments limit a variety of compositeness phenomena in the range from 1.9 to 8.3 TeV. These limits result from measurements of: the Ht spectrum (D0),

Timothy M. Braje, Roger W. Romani, Kevin P. Rauch

We consider the effect of rapid rotation on the light curves of neutron stars with hot polar caps. For $P \approx 3$ms spin periods, the pulse fractions can be as much as an order of magnitude larger than with simple slowly-rotating (Schwarzschild) estimates. Doppler boosting, in particular, leads to characteristic distortion and ``soft lags'' in the pulse p

G. Franzese, V. Cataudella, S. E. Korshunov, R. Fazio

We introduce a fully frustrated XY model with nearest neighbor (nn) and next nearest neighbor (nnn) couplings which can be realized in Josephson junction arrays. We study the phase diagram for $0\leq x \leq 1$ ($x$ is the ratio between nnn and nn couplings). When $x < 1/\sqrt{2}$ an Ising and a Berezinskii-Kosterlitz-Thouless transitions are present. Both cr

J. J. Blanco-Pillado, Ken D. Olum, Alexander Vilenkin

We rederive, using an elementary formalism, the general solution to the equations of motion for a superconducting string with a chiral (null) neutral current, earlier obtained by Carter and Peter. We apply this solution to show that the motion of such string loops is strictly periodic and analyze cusp-like behavior and vorton solutions of arbitrary shape. We

Gary T. Horowitz, Ian Low, A. Zee

We introduce a new brane-world model in which the bulk solution consists of outgoing plane waves. This is an exact solution to string theory with no naked singularities. The recently discussed self-tuning mechanism to cancel the cosmological constant on a brane is naturally incorporated. We show that even if the vacuum energy on the brane changes, e.g. due t

E. B. Jenkins, W. R. Oegerle, C. Gry, J. Vallerga

FUSE spectra of the white dwarf stars G191-B2B, GD 394, WD 2211-495 and WD 2331-475 cover the absorption features out of the ground electronic states of N I, N II, N III, O I and Ar I in the far ultraviolet, providing new insights on the origin of the partial ionization of the Local Interstellar Medium (LISM), and for the case of G191-B2B, the interstellar c

J. E. Hirsch, F. Marsiglio

The model of hole superconductivity predicts that the superfluid weight in the zero-frequency $\delta$-function in the optical conductivity has an anomalous contribution from high frequencies, due to lowering of the system's kinetic energy upon entering the superconducting state. The lowering of kinetic energy, mainly in-plane in origin, accounts for both th

S. K. Leggett, T. R. Geballe, Xiaohui Fan

We report the discovery of three cool brown dwarfs which fall in the effective temperature gap between the latest L dwarfs currently known, with no methane absorption bands in the 1-2.5um range, and the previously known methane (T) dwarfs, whose spectra are dominated by methane and water. The newly discovered objects were detected as very red objects in the

Timothy M. Braje, Roger W. Romani

We model the formation of magnetospheric components of millisecond pulsar light curves, deriving an approximate model for the curved space, `swept-back' dipole field and following photon emission, propagation, and scattering. Magnetospheric pulse components are strongly affected by rapid rotation and Schwarzschild effects.

Wei Gai, Paul Schoessow

We consider the use of a dielectric-loaded structure to extract rf energy from a high current electron drive beam as a power source for a high energy two-beam accelerator. This represents an alternative technique which we show to have some significant advantages over the use of the currently proposed corrugated metal structures as power extraction devices. W

M. H. Müser, L. Wenning, M. O. Robbins

A microscopic theory for the ubiquitous phenomenon of static friction is presented. Interactions between two surfaces are modeled by an energy penalty that increases exponentially with the degree of surface overlap. The resulting static friction is proportional to load, in accordance with Amontons' laws. However the friction coefficient between bare surfaces

Max Tegmark, Matias Zaldarriaga

We compute the joint constraints on ten cosmological parameters from the latest CMB measurements. The lack of a significant second acoustic peak in the latest Boomerang and Maxima data favors models with more baryons than Big Bang nucleosynthesis predicts, almost independently of what prior information is included. The simplest flat inflation models with pur

R. Kuhn, F. Krauss, B. Ivanyi, G. Soff

APACIC++ is a Monte-Carlo event-generator dedicated for the simulation of electron-positron annihilations into jets. Within the framework of APACIC++, the emergence of jets is identified with the perturbative production of partons as governed by corresponding matrix elements. In addition to the build-in matrix elements describing the production of two and th

Hugh Howards, John Luecke

A knot k is called ``strongly (n-1)-trivial.'' if there exists a projection of k, such that one can choose n crossings of the projection with the property that making the crossing changes corresponding to any of the $2^{n}-1$ nontrivial combinations of the selected crossings turns the original knot into the unknot. We prove that given any non-trivial knot k

H. Kaps, N. Büttgen, W. Trinkl, A. Loidl

7Li NMR measurements were performed in the metallic spinel LiV2O4. The temperature dependencies of the line width, the Knight shift and the spin-lattice relaxation rate were investigated in the temperature range 30 mK < T < 280 K. For temperatures T < 1 K we observe a spin-lattice relaxation rate which slows down exponentially. The NMR results can be explain

Tony Rothman, E. C. G. Sudarshan

Despite claims that Bell's inequalities are based on the Einstein locality condition, or equivalent, all derivations make an identical mathematical assumption: that local hidden-variable theories produce a set of positive-definite probabilities for detecting a particle with a given spin orientation. The standard argument is that because quantum mechanics ass

A. Wagner, W. P. Tan, K. Chalut, R. J. Charity

This article describes the crystal selection and quality control utilized to develop and calibrate a high resolution array of CsI(TI) scintillator crystals for the detection of energetic charged particles. Alpha sources are used to test the light output variation due to thallium doping gradients. Selection of crystals with better than 1% non-uniformity in li

P. de Bernardis, P. A. R. Ade, J. J. Bock, J. R. Bond

The blackbody radiation left over from the Big Bang has been transformed by the expansion of the Universe into the nearly isotropic 2.73K Cosmic Microwave Background. Tiny inhomogeneities in the early Universe left their imprint on the microwave background in the form of small anisotropies in its temperature. These anisotropies contain information about basi

B. Kampfer

The sequence of phase transitions during the hot history of the universe is followed within a phenomenological framework. Particular emphasis is put on the QCD confinement transition, which is at reach under earth laboratory conditions. A tepid inflationary scenario on the GUT scale with bubble grow at moderate supercooling is discussed.

Kurt Haller

We examine the relation between Coulomb-gauge fields and the gauge-invariant fields constructed in the temporal gauge for two-color QCD by comparing a variety of properties, including their equal-time commutation rules and those of their conjugate chromoelectric fields. We also express the temporal-gauge Hamiltonian in terms of gauge-invariant fields and sho

Guillermo A. Cecchi, Mariano Sigman, Jose-Manuel Alonso, Luis Martinez

Neuronal responses are conspicuously variable. We focus on one particular aspect of that variability: the precision of action potential timing. We show that for common models of noisy spike generation, elementary considerations imply that such variability is a function of the input, and can be made arbitrarily large or small by a suitable choice of inputs. O

R. L. Aptekar, D. D. Frederiks, S. V. Golenetskii, V. N. Il'inskii

Observational data on the bursting activity of all five known Soft Gamma Repeaters are presented. This information was obtained with Konus gamma-ray burst experiments on board Venera 11-14, Wind, and Kosmos-2326 spacecraft in the period from 1978 to 2000. These data on appearance rates, time histories, and energy spectra of repeated soft bursts obtained with

Luis C. Ho, Greg Rudnick, Hans-Walter Rix, Joseph C. Shields

Spectra taken with HST reveal that NGC 4450 emits Balmer emission lines with displaced double peaks and extremely high-velocity wings. This characteristic line profile, previously seen in a few nearby LINERs and in a small fraction of broad-line radio galaxies, can be interpreted as a kinematic signature of a relativistic accretion disk. We can reproduce the

J. C. N. de Araujo, A. Wang

A solution to the Einstein field equations that represents a rigidly rotating dust accompanied by a thin matter shell of the same type is found.

Ulrich Bilstein

We calculate the magnetization profiles of the $\sigma_j^x$ and $\sigma_j^z$ operators for the XX-model with hermitian boundary terms. We study the profiles on the finite chain and in the continuum limit. The results are discussed in the context of conformal invariance. We also discuss boundary excitations and their effect on the magnetization profiles.

Keiichi Umetsu, Masashi Tada, Toshifumi Futamase

The tidal gravitational field of galaxy clusters causes a coherent distortion of the images of background sources. Since the distribution of image distortions, namely the shear field, traces the local gravitational potential of a deflector, it can be used to reconstruct the two-dimensional mass distribution of clusters of galaxies. Moreover, the shear field

J. M. de Araujo, F. A. da Costa, F. D. Nobre

The effects of competing quadrupolar- and spin-glass orderings are investigated on a spin-1 Ising model with infinite-range random $p$-spin interactions. The model is studied through the replica approach and a phase diagram is obtained in the limit $p\to\infty$. The phase diagram, obtained within replica-symmetry breaking, exhibits a very unusual feature in

Julien Torres, Thierry Martin, Gordey B. Lesovik

Shot noise is studied in a single normal metal-superconductor (N-S) junction at finite frequency, and for branched N-S junctions at zero frequency. The noise spectral density displays a singularity at the Josephson frequency ($\omega = 2eV/\hbar$) when the applied bias is smaller than gap of the superconductor. Yet, in the limit $eV\gg \Delta$, quasiparticle

The FOCUS Collaboration

Using a high statistics sample of photoproduced charm particles from the FOCUS experiment at Fermilab, we compare the lifetimes of neutral D mesons decaying via D0 to K- pi+ and K- K+ to measure the lifetime differences between CP even and CP odd final states. These measurements bear on the phenomenology of D0 - D0bar mixing. If the D0 to K-pi+ is an equal m

M. Giovannini, M. Shaposhnikov

The hot plasma above the electroweak scale contains (hyper) charged scalar particles which are coupled to Abelian gauge fields. Scalars may interact with gravity in a non-conformally invariant way and thus their fluctuations can be amplified during inflation. These fluctuations lead to creation of electric currents and produce inhomogeneous distribution of c

Yuri N. Obukhov, Eugen J. Vlachynsky

The Proca wave equation describes a classical massive spin 1 particle. We analyze the gravitational interaction of this vector field. In particular, the spherically symmetric solutions of the Einstein-Proca coupled system are obtained numerically. Although at infinity the metric field approaches the usual Schwarzschild (Reissner-Nordstr\"om) limit, we demons

Paolo Salucci, Andreas Burkert

We establish the presence of a dark matter core radius, for the first time in a very large number of spiral galaxies of all luminosities. Contrary to common opinion we find that the sizes of these cores and the " DM core problem" are bigger for more massive spirals. As a result the Burkert profile provides an excellent mass model for dark halos around disk g

Seif Randjbar-Daemi

A brief review of aspects of gravity gauge theory correspondance inspired by string theory is presented.

H. A. Pinnow, W. Helfrich

We amplify previous arguments why mean curvature should be used as measure of integration in calculating the effective bending rigidity of fluid membranes subjected to a weak background curvature. The stiffening of the membrane by its fluctuations, recently derived for spherical shapes, is recovered for cylindrical curvature. Employing curvilinear coordinate

Herbert S. Wilf

We show that many theorems which assert that two kinds of partitions of the same integer $n$ are equinumerous are actually special cases of a much stronger form of equality. We show that in fact there correspond partition statistics $X$ and $Y$ that have identical distribution functions. The method is an extension of the principle of sieve-equivalence, and i

J. C. N. de Araujo, O. D. Miranda, O. D. Aguiar

A continuous stochastic background of gravitational waves (GWs) for burst sources is produced if the mean time interval between the occurrence of bursts is smaller than the average time duration of a single burst at the emission, i.e., the so called duty cycle must be greater than one. To evaluate the background of GWs produced by an ensemble of sources, dur

M. G. Kozlov, S. G. Porsev, I. I. Tupitsyn

In this letter we discuss how to include Breit interaction in calculations of low-energy properties of heavy atoms in accurate and effective way. In order to illustrate our approach we give some results for Cs and Tl.

A. Cucchieri, F. Karsch, P. Petreczky

We analyze the large distance and low-momentum behavior of the magnetic gluon propagator of the SU(2) gauge theory at finite temperature. Lattice calculations within the 4-dimensional as well as the effective, dimensionally reduced 3-dimensional gauge theories in generalized Landau gauges and MAG show that the magnetic propagator is strongly infrared suppres

Hans E. Plesser, Theo Geisel

The paradigm of stochastic resonance (SR)---the idea that signal detection and transmission may benefit from noise---has met with great interest in both physics and the neurosciences. We investigate here the consequences of reducing the dynamics of a periodically driven neuron to a renewal process (stimulation with reset or endogenous stimulation). This grea