May 2000 arXiv papers — page 10

E. M. Chudnovsky, D. A. Garanin

Recently, Bellessa et al in a Physical Review Letter entitled "Phonon-Assisted Tunneling in High-Spin Molecules: Experimental Evidence", reported observation of a peak in the imaginary part of the ac-susceptibility of Mn-12 molecular nanomagnet, that decreases strongly below 0.1 K down to 0.02 K. They explained this effect by a "phonon-induced tu

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

The infinite-range-interaction Ising spin glass is considered in the presence of an external random magnetic field following a trimodal (three-peak) distribution. The model is studied through the replica method and phase diagrams are obtained within the replica-symmetry approximation. It is shown that the border of the ferromagnetic phase may present first-o

Eric Brunet, Bernard Derrida

Reaction-diffusion problems are often described at a macroscopic scale by partial derivative equations of the type of the Fisher or Kolmogorov-Petrovsky-Piscounov equation. These equations have a continuous family of front solutions, each of them corresponding to a different velocity of the front. By simulating systems of size up to N=10^(16) particles at th

Z. Ropka

It has been derived that the Sommerfeld coefficient $γ$ as large as 25 J/K$^2$mol can be theoretically accounted for provided the charge f-electron fluctuations are substantially suppressed. This result enables the understanding of the heavy-fermion YbBiPt ($γ$ =8 J/K$^2$mol) as the spin fluctuator and should stimulate the experimental specific-heat research

Eric Brunet, Bernard Derrida

We consider the effect of a small cut-off epsilon on the velocity of a traveling wave in one dimension. Simulations done over more than ten orders of magnitude as well as a simple theoretical argument indicate that the effect of the cut-off epsilon is to select a single velocity which converges when epsilon tends to 0 to the one predicted by the marginal sta

R. J. Radwanski, Z. Ropka, R. Michalski

The orbital and spin moment of the Ni2+ ion in NiO has been calculated within the quasi-atomic approach. The orbital moment of 0.54 mB amounts at 0 K, in the magnetically-ordered state, to more than 20% of the total moment (2.53 mB). For this outcome, being in nice agreement with the recent experimental finding taking into account the spin-orbit coupling is

R. Roth, R. Evans, S. Dietrich

We present a versatile density functional approach (DFT) for calculating the depletion potential in general fluid mixtures. In contrast to brute force DFT, our approach requires only the equilibrium density profile of the small particles {\em before} the big (test) particle is inserted. For a big particle near a planar wall or a cylinder or another fixed big

Eric Brunet, Bernard Derrida

We show how to define and calculate the ground state energy of a system of quantum particles with delta attractive interactions when the number of particles n$is non-integer. The question is relevant to obtain the probability distribution of the free energy of a directed polymer in a random medium. When one expands the ground state energy in powers of the in

C. E. Creffield, Wolfgang Häusler, A. H. MacDonald

Low-energy properties of the homogeneous electron gas in one dimension are completely described by the group velocities of its charge (plasmon) and spin collective excitations. Because of the long range of the electron-electron interaction, the plasmon velocity is dominated by an electrostatic contribution and can be estimated accurately. In this Letter we r

R. Czopnik, P. Garbaczewski

We derive explicit forms of Markovian transition probability densities for the velocity space, phase-space and the Smoluchowski configuration-space Brownian motion of a charged particle in a constant magnetic field. By invoking a hydrodynamical formalism for those stochastic processes, we quantify a continual (net on the local average) heat transfer from the

Eric Brunet, Bernard Derrida

We calculate exactly the first cumulants of the free energy of a directed polymer in a random medium for the geometry of a cylinder. By using the fact that the n-th moment <Z^n> of the partition function is given by the ground state energy of a quantum problem of n interacting particles on a ring of length L, we write an integral equation allowing to expand

Achille Giacometti, Maurice Rossi

A novel algorithm is envisaged to extract the coupling parameters of the Kardar-Parisi-Zhang (KPZ) equation from experimental data. The method hinges on the Fokker-Planck equation combined with a classical least-square error procedure. It takes properly into account the fluctuations of surface height through a deterministic equation for space correlations. W

E. Mezzetti, A. Chiodoni, R. Gerbaldo, G. Ghigo

This paper studies the striking correlation between nanosized structural patterns in YBCO films and macroscopic transport current. A nanosized network of parallel Josephson junctions laced by insulating dislocations is almost mimicking the grain boundary structural network. It contributes to the macroscopic properties and accounts for the strong intergranula

Kicheon Kang

We study a mesoscopic superconducting ring threaded by a magnetic flux when the single particle level spacing is not negligible. It is shown that, for a superconducting ring with even parity, the behavior of persistent current is equivalent to what is expected in a bulk superconducting ring. On the other hand, we find that a ring with odd parity shows anomal

J. Sichelschmidt, A. Loidl, M. Baenitz, H. H. Otto

Temperature dependent EPR studies were performed on a single crystal of CuSiO3.This recently discovered compound is isostructural with the spin-Peierls compound CuGeO3. The EPR signals show different characteristics than those of CuGeO3 and aredue to Cu2+ spins located along quasi one-dimensional chains. For T > 8.2K the spin susceptibility closely follows t

S. K. Kwon, B. I. Min

We have investigated electronic structures of antiferromagnetic YBaCo_2O_5 using the local spin-density approximation (LSDA) + U method. The charge and orbital ordered insulating ground state is correctly obtained with the strong on-site Coulomb interaction. Co^{2+} and Co^{3+} ions are found to be in the high spin (HS) and intermediate spin (IS) state, resp

Zhi-Rong Liu, Bing-Lin Gu, Xiao-Wen Zhang

The thermally activated flips of the local spontaneous polarization in relaxors were simulated to investigate the effects of the applied-ac-field amplitude on the dielectric susceptibility. It was observed that the susceptibility increases with increasing the amplitude at low temperatures. At high temperatures, the susceptibility experiences a plateau and th

H. Kageyama, M. Nishi, N. Aso, K. Onizuka

We performed inelastic neutron scattering on the 2D Shastry-Sutherland system SrCu2(11BO3)2 with an exact dimer ground state. Three energy levels at around 3, 5 and 9 meV were observed at 1.7 K. The lowest excitation at 3.0 meV is almost dispersionless with a bandwidth of 0.2 meV at most, showing a significant constraint on a single-triplet hopping owing to

Zhi-Rong Liu, Jian-She Liu, Bing-Lin Gu, Xiao-Wen Zhang

The atomic ordering in complex perovskite alloys is investigated by the cluster variation method (CVM). For the 1/3\{111\}-type ordered structure, the order-disorder phase transition is the first order, and the order parameter of the 1:2 complex perovskite reaches its maximum near x=0.25. For the 1/2\{111\}-type ordered structure, the ordering transition is

E. M. Chudnovsky, D. A. Garanin

Recently Leuenbeger and Loss suggested a theory of phonon-assisted relaxation in a molecular nanomagnet Mn-12 that &#34;contrary to previous results is in reasonably good agreement ... with all experimental parameter values known so far&#34;. The purpose of this Comment is to show that the model of Leuenberger and Loss and its comparison with experiment are

Jiang-Ping Hu, Shou-Cheng Zhang

According to Wilson&#39;s theory of critical phenomena, critical exponents are universal functions of $d$, the dimension of space, and $n$, the dimension of the symmetry group. SO(5) theory of antiferromagnetism and superconductivity predicts a bicritical point where $T_N$ and $T_c$ intersect. By measuring critical exponents close to the bicritical point, an

Daniele Fargion

Tau Air-showers are the best trace of rarest Ultra High Energy neutrinos UHE $ν_τ$, $\barν_τ$ and $\barν_e$ at PeV and higher energy. $τ$ Air-showers may generate billion times amplified signals by their secondaries . Horizontal amplified $τ$ air-showers by $ν_τ N$ and UHE $\barν_{e} e$ at PeV emerging from mountain chain might be the most power-full imprint

K. Cunha, V. Smith, E. Parizot, D. Lambert

The boron abundances for two young solar-type members of the Orion association, BD -6 1250 and HD 294297, are derived from HST STIS spectra of the B I transition at 2496.771 A. The best-fit boron abundances for the target stars are 0.13 and 0.44 dex lower than the solar meteoritic value of log e(B)=2.78. An anticorrelation of boron and oxygen is found for Or

P. Severgnini

The connection between the sub-mm and the hard X-ray backgrounds is studied by comparing data at 2-10 keV and at 850um for a sample of 34 sources at fluxes (or limiting fluxes) which resolve most of the background in the two bands. These data were obtained with new SCUBA observations and by correlating data sets available from the literature. None of the 11

D. Massa, A. W. Fullerton, J. B. Hutchings, D. C. Morton

We present Far Ultraviolet Explorer (FUSE) spectra for three Magellanic Cloud O stars (Sk 80, Sk -67 05 and Sk -67 111) with repeated observations. The data demonstrate the capabilities of FUSE to perform time-resolved spectroscopy on extragalactic stars. The wavelength coverage of FUSE provides access to resonance lines due to less abundant species, such as

B. M. Peterson, I. M. McHardy, B. J. Wilkes, P. Berlind

We report on the results of a three-year program of coordinated X-ray and optical monitoring of the narrow-line Seyfert 1 galaxy NGC 4051. The rapid continuum variations observed in the X-ray spectra are not detected in the optical, although the time-averaged X-ray and optical continuum fluxes are well-correlated. Variations in the flux of the broad Hbeta li

Tod E. Strohmayer, Alaa I. Ibrahim

We present evidence of a 6.4 keV emission line during a burst from the soft gamma-ray repeater SGR 1900+14. The Rossi X-ray Timing Explorer (RXTE) monitored this source extensively during its outburst in the summer of 1998. A strong burst observed on August 29, 1998 revealed a number of unique properties. The burst exhibits a precursor and is followed by a l

Michele Orsini, Ettore Carretti, Stefano Cortiglioni

The Sky Polarization Observatory is an experiment selected by ESA for the Early Opportunity Phase onboard the International Space Station. SPOrt is the first payload specifically designed for polarization measurements, it will provide near full sky maps of the sky polarized emission at four microwave frequencies between 22 and 90 GHz. Current design of SPOrt

L. Stella, S. Campana, S. Mereghetti, D. Ricci

We report on a 20 ks BeppoSAX observation of the transient 2.5 ms X-ray pulsar SAX J1808.4-3658 in its quiescent state. A source at a level of ~ 3 x 10^-3 c/s was detected with the BeppoSAX/MECS at a position consistent with that of SAX J1808.4-3658. The inferred 0.5-10 keV luminosity was to that measured from other quiescent low mass X-ray transients hostin

Philippe Brax, Jerome Martin, Alain Riazuelo

Recent high precision measurements of the CMB anisotropies performed by the BOOMERanG and MAXIMA-1 experiments provide an unmatched set of data allowing to probe different cosmological models. Among these scenarios, motivated by the recent measurements of the luminosity distance versus redshift relation for type Ia supernovae, is the quintessence hypothesis.

A. Eckart, E. Schinnerer

We present first results of near-infrared integral field spectroscopy of the central 8&#39;&#39;$\times$8&#39;&#39; of the Wolf-Rayet nucleus of the barred spiral galaxy NGC 6764. In addition to stellar CO and Na I absorption lines as well as recombination lines of H and He I the K-band spectrum shows strong emission from molecular hydrogen. Analysis of the

Matt Burleigh, Martin Barstow

Using an Extreme Ultraviolet Explorer (EUVE) spectrum, we confirm the identification of a white dwarf companion to the B9.5V star 16 Dra (HD150100), and constrain its surface temperature to lie between 29,000K and 35,000K. This is the third B star + white dwarf non-interacting Sirius-type binary to be confirmed, after y Pup (HR2875, HD59635) and theta Hya (H

L. Piersanti, S. Cassisi, A. Tornambe&#39;

The role played by NCO reaction in the onset of the He flash in the He core of a RGB star and in low mass CO WDs accreting H/He rich matter is investigated.

W. Hackenberg, A. Eckart, R. I. Davies, S. Rabien

We report on high angular resolution near-infrared (NIR) observations of three galaxy clusters at different redshifts using adaptive optics (AO). In the case of the barred spiral \object{UGC 1347} in Abell 262 we presented the first AO results obtained using a laser guide star. The observations have been carried out with the MPE/MPIA adaptive optics laser gu

Subhabrata Majumdar, Biman Nath

We study the effect of cooling flows in galaxy clusters on the Sunyaev-Zel&#39;dovich (SZ) distortion and the possible cosmological implications. The SZ effect, alongwith X-ray observations of clusters, is used to determine the Hubble constant, $H_{\circ}$. Blank sky surveys of SZ effect are being planned to constrain the geometry of the universe through clu

Sui-Jian Xue, You-Hong Zhang, Jian-Sheng Chen

We present the analysis of archival data from ROSAT and ASCA of a serendipitous BL Lac object PKS 2316-423. Because of its featureless non-thermal radio/optical continuum, PKS 2316-423 has been called as a BL Lac candidate in the literature. PKS 2316-423 was evidently variable over the multiple X-ray observations, in particular, a variable high-energy tail o

J. L. Puchalla, R. Caldwell, K. L. Cruz, M. J. Devlin

We present multi-frequency maps of a portion of the Galactic Plane centered on a declination of -60 degrees with resolutions ranging from 0.2 to 0.9 degrees. The maps are optimized to detect unresolved source emission and are cross-calibrated against the planet Jupiter. We discuss six millimeter-bright regions, three of which are visible in all bands, and li

M. V. Sazhin, V. E. Zharov, T. A. Kalinina

Parallax measurements allow distances to celestial objects to be determined. Coupled with measurement of their position on the celestial sphere, it gives a full three-dimensional picture of the location of the objects relative to the observer. The distortion of the parallax value of a remote source affected by a weak microlensing is considered. This means th

Maya Paczuski, Kevin E. Bassler

We study a directed stochastic sandpile model of Self-Organized Criticality, which exhibits recurrent, multiple topplings, putting it in a separate universality class from the exactly solved model of Dhar and Ramaswamy. We show that in the steady-state all stable states are equally likely. Then we explicitly derive a discrete dynamical equation for avalanche

S. De Leo, G. C. Ducati

Motivated by a quaternionic formulation of quantum mechanics, we discuss quaternionic and complex linear differential equations. We touch only a few aspects of the mathematical theory, namely the resolution of the second order differential equations with constant coefficients. We overcome the problems coming out from the loss of the fundamental theorem of th

S. N. Cherry, M. R. Pennington

In the I=0 sector there are more scalar mesons than can fit in one $q{\bar q}$ nonet. Consequently, many have claimed that there is in fact more than one multiplet, perhaps both $q{\bar q}$ and $qq{\bar {qq}}$. Such proposals require the existence of at least two strange isodoublets (and their antiparticles). The current PDG Tables list just one state, the $

G. E. Volovik

Superfluid 3He-A gives example of how chirality, Weyl fermions, gauge fields and gravity appear in low energy corner together with corresponding symmetries, including Lorentz symmetry and local SU(N). This supports idea that quantum field theory (Standard Model or GUT) is effective theory describing low-energy phenomena. * Momentum space topology of fermioni

B. W. Harris, F. Chen, U. Mohideen

We report an improved precision measurement of the Casimir force using metallic gold surfaces. The force is measured between a large gold coated sphere and flat plate using an Atomic Force Microscope. The use of gold surfaces removes some theoretical uncertainties in the interpretation of the measurement. The forces are also measured at smaller surface separ

Norbert A&#39;Campo

A divide is a relative generic immersion of a finite union of copies of the unit interval in the unit disk. A divide defines a classical link in the 3- sphere, which is a fibered link if the image of the immersion is connected. We prove in this paper, that the Lefschetz number of the monodromy is 0. This result was known for divides, which correspond to real

Olivier Schiffmann

We give an explicit expression for the central elements of affine Hecke algebras of type A in the Coxeter presentation, in terms of (parabolic) affine Kazhdan-Lusztig polynomials. Our approach is based on a version of quantum affine Schur-Weyl duality involving the Hall algebra of a cyclic quiver, on the theory of canonical bases and on the higher-level q-de

D. Kotschick

We prove that manifolds admitting a Riemannian metric for which products of harmonic forms are harmonic satisfy strong topological restrictions, some of which are akin to properties of flat manifolds. Others are more subtle, and are related to symplectic geometry and Seiberg-Witten theory. We also prove that a manifold admits a metric with harmonic forms who

Gordon Chalmers, Johanna Erdmenger

We examine the dual correspondence between holographic IIB superstring theory and N=4 super Yang-Mills theory at finite values of the coupling constants. In particular we analyze a field theory strong-coupling expansion which is the S-dual of the planar expansion. This expansion arises naturally as the AdS/CFT dual of the IIB superstring scattering amplitude

Volker Braun

The Chern isomorphism determines the free part of the K-groups from ordinary cohomology. Thus to really understand the implications of K-theory for physics one must look at manifolds with K-torsion. Unfortunately there are not many explicit examples, and usually for very symmetric spaces. Cartesian products of RP^n are examples where the order of the torsion

Zuo-tang Liang, Tie-shi Li

We show that there is a correlation between the invariant mass of the produced ΛK^+, ΛK^+π^+π^- or ΛK^+ π^+π^-π^+π^- system in the exclusive reaction pp\to pΛK^+π^+π^-π^+π^- and the longitudinal or transverse momentum of $Λ$. Together with the longitudinal and transverse momentum dependence of Lambda polarization observed in inclusive reactions, such a corre

Paul H. Frampton

Working in the framework of three chiral neutrinos with Majorana masses, we investigate a scenario first realized in an explicit model by Zee: that the neutrino mass matrix is strictly off-diagonal in the flavor basis, with all its diagonal entries precisely zero. This CP-conserving ansatz leads to two relations among the three mixing angles $(θ_1, θ_2, θ_3)

Matthias Weiss, Tsampikos Kottos, Theo Geisel

We study the diffusive and localization properties of wavepackets in disordered wires in a magnetic field. In contrast to a recent supersymmetry approach our numerical results show that the decay rate of the steady state changes {\em smoothly} at the crossover from preserved to broken time-reversal symmetry. Scaling and fluctuation properties are also analyz

M. A. Jafarizadeh, M. Mirzaee, H. Aghlara

Using the S_3-symmetry of Sierpinski fractal resistor networks we determine the current distribution as well as the multifractals spectrum of moments of current distribution by using the real space renormalization group technique based on ([q/4]+1) independent Schure&#39;s invariant polynomials of inwards flowing currents.

Yu. A. Golubkov, M. Yu. Khlopov

The existence of antimatter domains in baryon asymmetrical Universe can appear as the cosmological consequence of particle theory in inflationary models with non-homogeneous baryosynthesis. Such a domain can survive in the early Universe and form globular cluster of antimatter stars in our Galaxy. The model of antimatter pollution of Galaxy and annihilation

Tomonori Totani

Here we present some critical discussions about the systematic uncertainty by dust extinction in the recent cosmological results of high-redshift Type Ia supernovae. First we argue that the currently available data do not robustly exclude the cosmologically significant extinction either by the reddening check or the dispersion argument because of the observa

A. Ya. Berdnikov, Ya. A. Berdnikov, A. N. Ivanov, V. A. Ivanova

We describe the quark gluon plasma (QGP) as a thermalized quark-gluon system, the thermalized QGP phase of QCD. The hadronization of the thermalized QGP phase is given in a way resembling a coalescence model with correlated quarks and anti-quarks. The input parameters of the approach are the spatial volumes of the hadronization. We introduce three dimensionl

Ivan K. Kostov

We present the exact solution of the Baxter&#39;s three-color problem on a random planar graph, using the random-matrix formulation of the problem, given by B. Eynard and C. Kristjansen. We find that the number of three-coloring of an infinite random graph is 0.9843 per vertex.

Hans C. Eggers, Thomas Dziekan, Martin Greiner

In the context of random multiplicative energy cascade processes, we derive analytical expressions for translationally invariant one- and two-point cumulants in logarithmic field amplitudes. Such cumulants make it possible to distinguish between hitherto equally successful cascade generator models and hence supplement lowest-order multifractal scaling expone

Takahiro Aoyama

We calculate the specific heat of the ideal gas obeying the generalized exclusion statistics (GES) in the continuum model and the tight binding model numerically. In the continuum model of 3-d space, the specific heat increases with statistical parameter at low temperature whereas it decreases with statistical parameter at high temperature. We find that the

H. Chamati, N. S. Tonchev

A detailed investigation of the scaling properties of the fully finite ${\cal O}(n)$ systems with long-range interaction, decaying algebraically with the interparticle distance $r$ like $r^{-d-σ}$, below their upper critical dimension is presented. The computation of the scaling functions is done to one loop order in the non-zero modes. The results are obtai

M. B. Halpern, J. E. Wang

Recently a construction was given for the stress tensors of all sectors of the general current-algebraic orbifold A(H)/H, where A(H) is any current-algebraic conformal field theory with a finite symmetry group H. Here we extend and further analyze this construction to obtain the mode formulation of each sector of each orbifold A(H)/H, including the twisted c

L. Everett, G. L. Kane, S. F. King

We examine the flavor structure of the trilinear superpotential couplings which can result from embedding the Standard Model within D brane sectors in Type IIB orientifold models, which are examples within the Type I string framework. We find in general that the allowed flavor structures of the Yukawa coupling matrices to leading order are given by basic var

V. B. Svetovoy, M. V. Lokhanin

We compare theoretical expectations for the Casimir force with the results of precise measurements. The force is calculated at finite temperature for multilayered covering of the bodies using the Lifshitz theory. We argue that the dielectric function of the metallization has to be directly measured to reach the necessary precision in the force calculation. W

Lee Rudolph

Four constructions of Seifert surfaces - Hopf plumbing, arborescent plumbing, basketry, and T-bandword handle decomposition - are described, and some interrelationships found, e.g.: arborescent Seifert surfaces are baskets; Hopf-plumbed baskets are precisely homogeneous T-bandword surfaces. A Seifert surface is Hopf-plumbed if it is a 2-disk D or if it can b

Victor M. Buchstaber, Taras E. Panov

Let $ρ:(D^2)^m\to I^m$ be the orbit map for the diagonal action of the torus $T^m$ on the unit poly-disk $(D^2)^m$, $I^m=[0,1]^m$ is the unit cube. Let $C$ be a cubical subcomplex in $I^m$. The moment-angle complex $\ma(C)$ is a $T^m$-invariant bigraded cellular decomposition of the subset $ρ^{-1}(C)\subset(D^2)^m$ with cells corresponding to the faces of $C

Jungkai A. Chen, Christopher D. Hacon

Let $X$ be a smooth complex projective algebraic variety of maximal Albanese dimension. We give a characterization of $κ(X)$ in terms of the set $V^0(X,ω_{X})$ $:=\{P\in {\text{\rm Pic}}^0(X)|h^0(X, ω_X \otimes P) \ne 0\}$. An immediate consequence of this is that the Kodaira dimension $κ(X)$ is invariant under smooth deformations. We then study the plurican

Alessandro Arsie

Developing a previous idea of Faltings, we characterize the complete intersections of codimension 2 in P^n, n>=3, over an algebraically closed field of any characteristic, among l.c.i. X, as those that are subcanonical and scheme-theoretically defined by p<=n-1 equations. Moreover, we give some other results assuming that the normal bundle of X extends to a

Kurt Just, James Thevenot

It should be of interest, whether Dirac&#39;s equation involves all 16 basis elements of his Clifford algebra $Cl_D.$ These include the 6 `tensorial&#39; $σ^{μν}$ with which the `Pauli terms&#39; are formed. We find that these violate a basic axiom of any *-algebra, when Dirac&#39;s $Ψ$ is canonical. Then the Dirac operator is spanned only by the 10 elements

David J. Toms

The quantisation of a scalar field in the five-dimensional model suggested by Randall and Sundrum is considered. Using the Kaluza-Klein reduction of the scalar field, discussed by Goldberger and Wise, we sum the infinite tower of modes to find the vacuum energy density. Dimensional regularisation is used and we compute the pole term needed for renormalisatio

Hidenori Sonoda

In a previous paper we have shown how the Wilsonian renormalization group naturally leads to the equivalence of the standard QED with a matter-only theory. In this paper we give an improved explanation of the equivalence and discuss, as an example, the equivalence of a chiral QED in the Higgs phase with a matter-only theory. Ignoring the contributions suppre

M. Chaichian, A. Demichev, P. Presnajder

We consider a field theoretical model on the noncommutative cylinder which leads to a discrete-time evolution. Its Euclidean version is shown to be equivalent to a model on the complex $q$-plane. We reveal a direct link between the model on a noncommutative cylinder and the deformed Virasoro algebra constructed earlier on an abstract mathematical background.

M. Maris, S. T. Petcov

The current Super-Kamiokande data on the D-N asymmetry between the the day event rate and the {\it Night} and {\it Core} event rates, produced by solar neutrinos which respectively cross the Earth along any trajectory and cross the Earth core before reaching the detector, imply rather stringent constraints on the MSW small mixing angle (SMA) $ν_e \to ν_{μ(τ)

L3 Collaboration

The measurements of hadron and lepton-pair production cross sections and leptonic forward-backward asymmetries performed with the L3 detector at centre-of-mass energies between 130 GeV and 189 GeV are used to search for new physics phenomena such as: contact interactions, exchange of virtual leptoquarks, scalar quarks and scalar neutrinos, effects of TeV str

Z. G. Dai, T. Lu

Recent observations on the GRB 000301c afterglow show that three breaks appear in the R-band light curve, and in particular the decay slope at late times is as steep as -3.0. This unusual afterglow is clearly inconsistent with the standard afterglow shock model. Here we propose a non-standard model for the unusual R-band afterglow of GRB 000301c. In this mod

R. Zamanov, J. Marti

We report our attempts to detect and confirm a narrow moving component in the H-alpha emission line of the radio emitting Be/X-ray binary LSI+61 303 (V615 Cas, GT0236+610). The existence of this spectral feature was already suspected in the past. As a result, we find that this component does exist and that its radial velocity varies in agreement with the rad

David Tong

We discuss several aspects of three dimensional N=2 supersymmetric gauge theories coupled to chiral multiplets. The generation of Chern-Simons couplings at low-energies results in novel behaviour including compact Coulomb branches, non-abelian gauge symmetry enhancement and interesting patterns of dynamically generated potentials. We further show how, given

Takao Morinari, Manfred Sigrist

The London penetration depth for the unconventional superconductor Sr$_2$RuO$_4$ is analyzed assuming an order parameter which breaks time reversal symmetry and parity simultaneously. Such a superconducting state possesses chiral quasiparticle states with subgap energies at the surface. We show that these subgap states can give a significant contribution to

A. M. Bratkovsky, A. P. Levanyuk

The actual mechanism of polarization switching in ferroelectrics remains a puzzle for many decades, since the usually estimated barrier for nucleation and growth is insurmountable (&#34;paradox of the coercive field&#34;). To analyze the mechanisms of the nucleation we consider the exactly solvable case of a ferroelectric film with a &#34;dead&#34; layer at

Klaus Behrndt

We discuss domain wall solutions of 5-dimensional supergravity corresponding to a cosine-superpotential, which is derived by a gauging of the two Abelian isometries of the scalar coset SU(2,1)/U(2). We argue that this potential can be obtained from M-theory compactification in the presence of G-fluxes and an M5-brane instanton gas. If we decouple the volume

Dallas C. Kennedy

The long-standing deficit of measured versus predicted solar neutrino fluxes is re-examined in light of possible astrophysical solutions. In the last decade, solar neutrino flux and helioseismic measurements have greatly strengthened the case for non-astrophysical solutions. But some model- independent tests remain open.

J. A. Nieto, L. N. Alejo-Armenta

By using tensor analysis, we find a connection between normed algebras and the parallelizability of the spheres S$^1$, S$^3$ and S$^7.$ In this process, we discovered the analogue of Hurwitz theorem for curved spaces and a geometrical unified formalism for the metric and the torsion. In order to achieve these goals we first develope a proof of Hurwitz theore

Claude LeBrun

As was recently pointed out by McMullen and Taubes [Math. Res. Lett. 6 (1999) 681-696], there are 4-manifolds for which the diffeomorphism group does not act transitively on the deformation classes of orientation-compatible symplectic structures. This note points out some other 4-manifolds with this property which arise as the orientation-reversed versions o

K. Petrovay

The precise nature of photospheric flows, and of the transport effects they give rise to, has been the subject of intense debate in the last decade. Here we attempt to give a brief review of the subject emphasizing interdisciplinary (solar physics - turbulence theory) aspects, key open questions, and recent developments.

Peter Prelovsek

The origin of the universal optical conductivity form sigma(omega) ~ (1-e^(omega/T))/omega established in numerical model studies of doped antiferromagnets and consistent with experiments on cuprates near optimal doping is discussed. It is shown that such a behaviour appears quite generally when the single-particle excitations are overdamped and their relaxa

G. Arutyunov, S. Frolov, A. C. Petkou

We present a detailed analysis of the 4-point functions of the lowest weight chiral primary operators $O^{I} \sim \tr ϕ^{(i}ϕ^{j)}$ in $\N =4$ SYM$_4$ at strong coupling and show that their structure is compatible with the predictions of AdS/CFT correspondence. In particular, all power-singular terms in the 4-point functions exactly coincide with the contrib

B. Spivak

We discuss properties of strongly correlated two-dimensional electron gas in semiconductor layers at low electron concentrations assuming that the electron liquid is close to crystalization. Analogy with the theory of 3He is emphasized.

Felix Finster, Niky Kamran, Joel Smoller, Shing-Tung Yau

We consider the Cauchy problem for the massive Dirac equation in the non-extreme Kerr-Newman geometry outside the event horizon. We derive an integral representation for the Dirac propagator involving the solutions of the ODEs which arise in Chandrasekhar&#39;s separation of variables. It is proved that for initial data in L^\infty_loc near the event horizon

J. Gattnar, K. Langfeld, A. Schafke, H. Reinhardt

The high-temperature phase of SU(2) Yang-Mills theory is addressed by means of dimensional reduction with a special emphasis on the properties of center vortices. For this purpose, the vortex vacuum which arises from center projection is studied in pure 3-dimensional Yang-Mills theory as well as in the 3-dimensional adjoint Higgs model which describes the hi

Klaus Morawetz

The influence of an external electric field on the current in charged systems is investigated. The results from the classical hierarchy of density matrices are compared with the results from the quantum kinetic theory. The kinetic theory yields a systematic treatment of the nonlinear current beyond linear response. To this end the dynamically screened and fi

Stavros Garoufalidis, Mikhail Goussarov, Michael Polyak

A clover is a framed trivalent graph with some additional structure, embedded in a 3-manifold. We define surgery on clovers, generalizing surgery on Y-graphs used earlier by the second author to define a new theory of finite-type invariants of 3--manifolds. We give a systematic exposition of a topological calculus of clovers and use it to deduce some importa

R. I. Hynes, C. W. Mauche, C. A. Haswell, C. R. Shrader

We present multiwavelength observations of the newly discovered X-ray transient XTE J1118+480 obtained in the rising phase of the 2000 April outburst. This source is located at unusually high Galactic latitude and in a very low absorption line of sight. This made the first EUVE spectroscopy of an X-ray transient outburst possible. Together with our HST, RXTE

Shin&#39;ichi Imai, Naoki Sasakura

We discuss scalar quantum field theories in a Lorentz-invariant three-dimensional noncommutative space-time. We first analyze the one-loop diagrams of the two-point functions, and show that the non-planar diagrams are finite and have infrared singularities from the UV/IR mixing. The scalar quantum field theories have the problem that the violation of the mom

T. Kodama, R. G. Bower

We address the current crucial issues on the formation and evolution of cluster galaxies: ie., connection between the Butcher-Oemler effect, assembly of cluster galaxies, truncation of star formation, and the origin of S0 galaxies. We construct the field corrected colour-magnitude (CM) diagrams for 7 CNOC clusters (0.23<z<0.43) and Coma, and illustrate the e

G. Morigi, H. Walther

We study from the point of view of quantum logic the properties of the collective oscillations of a linear chain of ions trapped in a linear Paul trap and composed of two ion species. We discuss extensively sympathetic cooling of the chain and the effect of anharmonicity on laser-cooling and quantum-information processing.

Michio Watanabe, Kohei M. Itoh, Youiti Ootuka, Eugene E. Haller

We have determined the localization length ξand the impurity dielectric susceptibility χ_{\rm imp} as a function of Ga acceptor concentrations (N) in nominally uncompensated ^{70}Ge:Ga just below the critical concentration (N_c) for the metal-insulator transition. Both ξand χ_{\rm imp} diverge at N_c according to the functions ξ\propto(1-N/N_c)^{-ν} and χ_{\

Mariano Cadoni, Marco Cavaglia&#39;

We show that weak-coupled two-dimensional dilaton gravity on Anti-de Sitter space can be described by the dynamics of an open string. Neumann and Dirichlet boundary conditions for the string lead to two different realizations of the Anti-de Sitter/Conformal Field Theory correspondence. In particular, in the Dirichlet case the thermodynamical entropy of two-d

I. B. Khriplovich, R. V. Korkin

The paper has been withdrawn.

A. S. Alexandrov, A. F. Andreev

We describe strongly attractive carriers in cuprates in the framework of a simple quasi-one dimensional Hamiltonian with a local attraction. In contrast with the conventional BCS theory there are two energy scales, a temperature independent incoherent gap $Δ_p$ and a temperature dependent coherent gap $Δ_c (T)$ combining into one temperature dependent global

Yong Zhang

In this paper we construct path integral representations of the boundary states in some special backgrounds such as the U(1) gauge field background, the linear dilaton background and the open string tachyon background. The initial purpose of this paper is to construct a general solution of the boundary conformal field theory with the analytical approach, mai

Sergei Alexandrov

An so(4,C)-covariant hamiltonian formulation of a family of generalized Hilbert-Palatini actions depending on a parameter (the so called Immirzi parameter) is developed. It encompasses the Ashtekar-Barbero gravity which serves as a basis of quantum loop gravity. Dirac quantization of this system is constructed. Next we study dependence of the quantum system

Yoshio Kikukawa, Yoichi Nakayama

We consider the cohomological classification of the 4+2-dimensional topological field, which is proposed by Lüscher, for SU(2)_L \times U(1)_Y electroweak theory. The dependence on the admissible abelian gauge field of U(1)_Y is determined through topological argument, with SU(2)_L gauge field fixed as background. We then show the exact cancellation of the l