December 1999 arXiv papers — page 25

A. B. Zorin, S. V. Lotkhov, H. Zangerle, J. Niemeyer

We report on the investigation of Al single electron structures equipped with miniature (8 um long) on-chip Cr resistors of R > R_k = h/e^2 = 25.8 kOhm. From the measurement of the Coulomb blockade in single-junction structures we evaluated the self-capacitance of our resistors per unit length, c = 62 aF/um. We demonstrate that the cotunneling current in the

H. Elsinger, J. Wosnitza, S. Wanka, J. Hagel

High-resolution specific-heat measurements of the organic superconductor kappa-(BEDT-TTF)_2Cu[N(CN)_2]Br in the superconducting (B = 0) and normal (B = 14 T) state show a clearly resolvable anomaly at Tc = 11.5 K and an electronic contribution, Ces, which can be reasonably well described by strong-coupling BCS theory. Most importantly, Ces vanishes exponenti

I. A. Fomin, J. -P. Brison

We discuss a model based on a field-induced mixture of two odd-parity irreducible representations to explain the unusual features of Hc2(T) in the heavy fermion compound UBe13. We compare its predictions with recent pressure measurements as well as with the most prominent theoretical models which have been proposed up to now.

J. Gonzalez

We study the finite-size scaling of the free energy of the Ising model on lattices with the topology of the tetrahedron and the octahedron. Our construction allows to perform changes in the length scale of the model without altering the distribution of the curvature in the space. We show that the subleading contribution to the free energy follows a logarithm

Noelle Pottier, Alain Mauger

The two-time correlation function of the displacement of a free quantum Brownian particle with respect to its position at a given time is calculated analytically in the framework of the Caldeira and Leggett ohmic dissipation model (linear coupling of the particle with a thermal bath with a continuum of modes, proportional to the frequency at low frequency).

Biplab Chattopadhyay, B. Bandyopadhyay, Asok Poddar, P. Mandal

Suppression of T_c in bilayer bismuth and thallium cuprates, by substitution of Co impurities at Cu sites, are taken for examination. T_c suppression data on differently doped Bi2212 and Tl2212 are analysed within the unitary pair-breaking formalism due to Abrikosov and Gorkov, by fitting data points to a phenomenological relation valid for weak coupling d-w

H. Kleinert

We point out that the smectic-nematic phase transition may considered as a transition of a stack of membranes in $2+ε$ dimensions, in which the layers become so wrinkled that they interpenetrate each other are no longer distinguishable.

Hikaru Kawamura

There recently accumulated growing numerical and experimental evidence that a novel glassy zero-field phase characterized by the spontaneously broken time-reversal symmetry, a chiral-glass phase, is realized in certain ceramic high-$T_c$ superconductors. Existence of frustration in zero external field, arising from the d-wave pairing symmetry of high-$T_c$ s

T. Mizokawa, D. I. Khomskii, G. A. Sawatzky

We have explored spin, charge and orbitally ordered states in La1-xSrxMnO3 (0 < x < 1/2) using model Hartree-Fock calculations on d-p-type lattice models. At x=1/8, several charge and orbitally modulated states are found to be stable and almost degenerate in energy with a homogeneous ferromagnetic state. The present calculation indicates that a ferromagnetic

Beom Jun Kim, Petter Minnhagen

The dynamical vortex response of a two-dimensional array of the resistively shunted Josephson junctions in a perpendicular magnetic field is inferred from simulations. It is found that, as the magnetic field is increased at a fixed temperature, the response crosses over from normal to anomalous, and that this crossover can be characterized by a single dimens

J. D. Naud, Leonid P. Pryadko, S. L. Sondhi

The edge state theory of a class of symmetric double-layer quantum Hall systems with interlayer electron tunneling reduces to the sum of a free field theory and a field theory of a chiral Bose field with a self-interaction of the sine-Gordon form. We argue that the perturbative renormalization group flow of this chiral sine-Gordon theory is distinct from the

Yuriy Makhlin, Gerd Schoen, Alexander Shnirman

Several physical realizations of quantum bits have been proposed. Of those, nano-electronic devices appear most suitable for large-scale integration and potential applications. We suggest to use low-capacitance Josephson junctions, exploiting the coherence of tunneling in the superconducting state combined with the possibility to control individual charges b

Rita M. Sambruna

Results from recent multiwavelength observations of blazars are reviewed, with particular emphasis on those involving the Rossi X-ray Timing Explorer (RXTE). I discuss blazars&#39; spectral energy distributions, their correlated variability at various energies, and the insights they offer on the physical processes in the jet. New results on Mrk 501, PKS 2155

K. Hurley

On the average, one new publication on cosmic gamma-ray bursts enters the literature every day. The total number now exceeds 4100. I present here a complete bibliography which can be made available electronically to interested parties.

Andy Shearer, Aaron Golden, Gregory Beskin

Observations of the 5 confirmed optical pulsars indicate that the peak emission scales according to the outer field strength. We show that this gives gives further confirmation that a simple phenomenological models such as Pacini and Salvati (1987) still have validity. Furthermore we show that the Crab pulsar exhibits unpulsed emission which further complica

D. Trevese, G. Cirimele, M. De Simone

A new analysis of velocity distribution, optical photometry and X-ray surface brightness from ROSAT PSPC data of the galaxy cluster A 2319 is presented. The temperature profile derived from ASCA data (Markevitch et al.,1996) is taken into account. A method to check the hydrostatic model in the presence of a temperature gradient is proposed. Consistency of th

G. Tagliaferri, G. Ghisellini, P. Giommi, L. Chiappetti

ON 231 was observed with BeppoSAX in May and June 1998, following an exceptional optical outburst which occured in April--May. We measured the X-ray spectrum from 0.1 up to 100 keV. In both occasions the spectrum had a concave shape, with a break detected at about 4 and 2.5 keV, respectively. We interpret the steeper component at energies below the break as

A. A. Starobinsky

The existence of a positive and possibly varying Lambda-term opens a much wider field of possibilities for the future of our Universe than it was usually thought before. Definite predictions may be made for finite (though very large) intervals of time only, as well as in other branches of science. In particular, our Universe will continue to expand as far as

Jacco Th. van Loon

The mass-loss rates and dust-to-gas ratios of obscured Asymptotic Giant Branch (AGB) stars are investigated for samples with different initial metallicities: in the Small and Large Magellanic Clouds (SMC & LMC) and in the Milky Way. The properties of their circumstellar envelopes can be explained in a consistent way if, both for obscured M-type AGB stars and

Jose F. Gomez, Paola D&#39;Alessio

Molecular line observations that could resolve protoplanetary disks of ~100 AU both spatially and kinematically would be a useful tool to unambiguously identify these disks and to determine their kinematical and physical characteristics. In this work we model the expected line emission from a protoplanetary disk irradiated by an infalling envelope, addressin

E. Villaver, A. Manchado, G. Garcia-Segura

Multiple shell planetary nebulae (MSPNe) are most likely a consequence of the modulation of the mass-loss rate during the thermal pulses on the AGB. By using numerical simulations of their formation, the models&#39; predictions and the history of the winds can be investigated. As their halos have low densities and expansion velocities, MSPNe are expected to

Sun Hong Rhie, David P. Bennett

In a line caustic crossing microlensing event, the caustic line moving across the surface of the source star provides a direct method to measure the integrated luminosity profile of the star. Combined with the enormous brightening at the caustic crossings, microlensing offers a promising tool for studying stellar luminosity profiles. We derive the amplificat

V. V. Gvaramadze

The nature of the Vela X-ray &#34;jet&#34;, recently discovered by Markwardt & Ögelman (1995), is examined. It is suggested that the &#34;jet&#34; arises along the interface of domelike deformations of the Rayleigh-Taylor unstable shell of the Vela supernova remnant; thereby the &#34;jet&#34; is interpreted as a part of the general shell of the remnant. The

Philippe Brax, Jerome Martin

Recent observations seem to suggest that our Universe is accelerating implying that it is dominated by a fluid whose equation of state is negative. Quintessence is a possible explanation. In particular, the concept of tracking solutions permits to adress the fine-tuning and coincidence problems. We study this proposal in the simplest case of an inverse power

Rolf Walder, Doris Folini

Aspects of the wind-dynamics in symbiotic binaries, colliding winds and accretion, are reviewed. Inconsistencies between theory and observations of the hot star wind are discussed. If the hot star wind were governed by CAK theory, nearly all symbiotics would be colliding wind binaries. For the case of colliding winds, 3D hydrodynamical simulations reveal tha

W. Collmar, K. Bennett, H. Bloemen, W. Hermsen

The COMPTEL experiment aboard the COMPTON Gamma-Ray Observatory (CGRO) has observed the prominent TeV-blazars Mkn 421 and Mkn 501 many times between the start of its mission in April &#39;91 and December &#39;98. This paper reports first COMPTEL results from mainly time-averaged (CGRO Cycles) data. No evidence for both sources is found up to the end Cycle VI

Georges Meylan, Stephane Leon, Francoise Combes

We present our study of the 2-D structures of the tidal tails associated with 20 galactic globular clusters, structures obtained by using the wavelet transform to detect weak structures at large scale and filter the strong background noise for the low galactic latitude clusters (Leon, Meylan & Combes 2000). We also present N-body simulations of globular clus

F. Sabbadin, E. Cappellaro, S. Benetti, M. Turatto

Spatially resolved, long-slit echellograms at different position angles of the bright, low excitation planetary nebula NGC 40 indicate that, the higher is the gas excitation, the faster is the radial motion, thus confirming the overturn of the Wilson law already suggested by Sabbadin and Hamzaoglu (1982). New reduction procedures, giving the radial trends of

Zakir F. Seidov

Highly personalysed and subjective review of studies of the equilibrium, pulsations and stability of stars with the first-order phase transition.

Douglas Scott

This is the obligatory Cosmic Microwave Background review. I discuss the current status of CMB anisotropies, together with some points on the related topic of the Far-Infrared Background. We have already learned a number of important things from CMB anisotropies. Models which are in good shape have: approximately flat geometry; cold dark-matter, plus somethi

Steven S. Gubser

The radiation-dominated k=0 FRW cosmology emerges as the induced metric on a codimension one hypersurface of constant extrinsic curvature in the five-dimensional AdS-Schwarzschild solution. That we should get FRW cosmology in this way is an expected result from AdS/CFT in light of recent comments regarding the coupling of gravity to &#34;boundary&#34; confor

C. Pastorino, Z. Gamba

Alpha S8 is the most stable crystalline form, at ambient pressure and temperature (STP), of elemental sulfur. In this paper we analyze the zero pressure low temperature part of the phase diagram of this crystal, in order to test a simple and flexible model molecule. The calculations consist in a series of molecular dynamics (MD) simulations, performed in the

D. Kharzeev, E. Levin

We propose a new non-perturbative approach to hadronic interactions at high energies and small momentum transfer, which is based on the scale anomaly of QCD and emphasizes the role of semi-classical vacuum fields. We find that the hadron scattering amplitudes exhibit Regge behavior and evaluate the intercept alpha(0) of the corresponding trajectory. Both the

P. Di Bari, R. Foot

We deal with the problem of the final sign of the neutrino asymmetry generated by active-sterile neutrino oscillations in the Early Universe solving the full momentum dependent quantum kinetic equations. We study the parameter region $10^{-2} \stackrel{<}{\sim} |δm^2|/eV^2\le 10^3$. For a large range of $\sin^2 2θ_0$ values the sign of the neutrino asymmetry

G. M. Huber, G. J. Lolos, E. J. Brash, S. Dumalski

The 3He(gamma,pi^+/- p) reactions were measured simultaneously over a tagged photon energy range of 800<E_gamma<1120 MeV, well above the Delta resonance region. An analysis was performed to kinematically isolate Delta knockout events from conventional Delta photoproduction events, and a statistically significant excess of pi+p events was identified, consiste

Brian Mangum, Theodore Stanford

If L_1 and L_2 are two Brunnian links with all pairwise linking numbers 0, then we show that L_1 and L_2 are equivalent if and only if they have homeomorphic complements. In particular, this holds for all Brunnian links with at least three components. If L_1 is a Brunnian link with all pairwise linking numbers 0, and the complement of L_2 is homeomorphic to

G. F. R. Ellis, D. C. Roberts, D. Solomons, P. K. S. Dunsby

We examine the string cosmology equations with a dilaton potential in the context of the Pre-Big Bang Scenario with the desired scale factor duality, and give a generic algorithm for obtaining solutions with appropriate evolutionary properties. This enables us to find pre-big bang type solutions with suitable dilaton behaviour that are regular at $t=0$, ther

S. Jadach, B. F. L. Ward, Z. Was

We present the Monte Carlo event generator KK version 4.13 for precision predictions of the Electroweak Standard Model for the process $e^+e^-\to f\bar{f} +nγ$, $f=μ,τ,d,u,s,c,b$ at centre of mass energies from $τ$ lepton threshold to 1TeV, that is for LEP, SLC, future Linear Colliders, $b,c,τ$-factories etc. Effects due to photon emission from initial beams

M. Boettcher

The time and angle dependent line and continuum emission from a dense torus around a cosmological gamma-ray burst source is simulated, taking into account photoionization, collisional ionization, recombination, and electron heating and cooling due to various processes. The importance of the hydrodynamical interaction between the torus and the expanding blast

K. W. Madison, F. Chevy, W. Wohlleben, J. Dalibard

Using a focused laser beam we stir a Bose-Einstein condensate of 87Rb confined in a magnetic trap and observe the formation of a vortex for a stirring frequency exceeding a critical value. At larger rotation frequencies we produce states of the condensate for which up to four vortices are simultaneously present. We have also measured the lifetime of the sing

Peter Orland, Gordon W. Semenoff

We examine the structure of the potential energy of 2+1-dimensional Yang-Mills theory on a torus with gauge group SU(2). We use a standard definition of distance on the space of gauge orbits. A curve of extremal potential energy in orbit space defines connections satisfying a certain partial differential equation. We argue that the energy spectrum is gapped

Peter Arnold

A Langevin equation with multiplicative noise is an equation schematically of the form dq/dt = -F(q) + e(q) xi, where e(q) xi is Gaussian white noise whose amplitude e(q) depends on q itself. Such equations are ambiguous, and depend on the details of one's convention for discretizing time when solving them. I show that these ambiguities are uniquely resolved

Zoheir Aouissat

The Holstein-Primakoff mapping for pairs of bosons is extended in order to accommodate single boson mapping. The proposed extension allows a variety of applications and especially puts the formalism at finite temperature on firm grounds. The new mapping is applied to the O(N+1) anharmonic oscillator with global symmetry broken down to O(N). It is explicitly

A. L. Maroto, J. R. Pelaez

We study the high-energy equivalence between helicity 1/2 gravitinos and goldstinos in order to calculate the production of gravitinos in time-dependent scalar and gravitational backgrounds. We derive this equivalence for equations of motion, paying attention to some subtleties, mainly due to external sources, that are not present in the standard proofs. We

Almut Beige, Daniel Braun, Peter L. Knight

We describe the decoherence-free subspace of N atoms in a cavity, in which decoherence due to the leakage of photons through the cavity mirrors is suppressed. We show how the states of the subspace can be entangled with the help of weak laser pulses, using the high decay rate of the cavity field and strong coupling between the atoms and the resonator mode. T

E. Kh. Akhmedov, G. C. Branco, M. N. Rebelo

We show that in the framework of three light neutrino species with hierarchical masses and assuming no fine tuning between the entries of the neutrino mass matrix, one can use the solar neutrino data to obtain information on the element $U_{e3}$ of the lepton mixing matrix. Conversely, a measurement of $U_{e3}$ in atmospheric or long baseline accelerator or

Alessandro Cuccoli, Andrea Fubini, Valerio Tognetti, Ruggero Vaia

The phase diagram of two dimensional Josephson arrays is studied by means of the mapping to the quantum XY model. The quantum effects onto the thermodynamics of the system can be evaluated with quantitative accuracy by a semiclassical method, the {\em pure-quantum self-consistent harmonic approximation}, and those of dissipation can be included in the same f

J. -M. Frere, M. V. Libanov, S. V. Troitsky

Naturally small Majorana neutrino masses arise from nonstandard supersymmetry breaking terms. This mechanism works in the minimal supersymmetric framework and does not require extra particles or new mass scales. It could also be responsible for proton decay even in the absence of Grand Unification.

Alan Carey, Jouko Mickelsson

We consider the canonical quantization of fermions on an odd dimensional manifold with boundary, with respect to a family of elliptic hermitean boundary conditions for the Dirac hamiltonian. We show that there is a topological obstruction to a smooth quantization as a function of the boundary conditions. The obstruction is given in terms of a gerbe and its D

Thomas Schauerte, Johann Kroha, Peter Wölfle

We calculate the exponents of the threshold singularities in the photoemission spectrum of a deep core hole and its X-ray absorption spectrum in the framework of a systematic many-body theory of slave bosons and pseudofermions (for the empty and occupied core level). In this representation, photoemission and X-ray absorption can be understood on the same foo

Tohsuke Urabe

Assume that there exists a hypersurface singularity which cannot be resolved by iterated monoidal transformations in positive characteristic. We show that in the set of defining functions of hypersurface singularities which cannot be resolved, we can find a function satisfying very strong conditions. By these conditions we may be able to deduce a contradicti

K. M. Bekarian, A. A. Melkonian

The Ricci curvature criterion is used for the investigation of the relative instability of several configurations of N-body gravitating systems. It is shown, that the systems with double massive centers are more unstable than the homogeneous systems and those with one massive center. In general this shows the efficiency of the Ricci curvature method introduc

Satoshi Nozawa, Naoki Itoh, Youhei Kawana, Yasuharu Kohyama

We present an accurate analytic fitting formula for the numerical results for the relativistic corrections to the thermal Sunyaev-Zel&#39;dovich effect for clusters of galaxies. The numerical results for the relativistic corrections have been obtained by numerical integration of the collision term of the Boltzmann equation. The fitting is carried out for the

W. Melnitchouk, I. R. Afnan, F. Bissey, A. W. Thomas

In a recent paper Yang and Bodek extracted the free neutron structure function at large x by extrapolating the density dependence of the nuclear EMC ratios to the deuteron. We clarify why this approach is ill-defined for light nuclei, and introduces a large theoretical bias into the extraction of F_2n at large x.

Bo Qin, Xiang-Ping Wu

Heavy particles in galaxy clusters tend to be more centrally concentrated than light ones according to the Boltzmann distribution. An estimate of the drift velocity suggests that it is possible that the helium nuclei may have entirely or partially sedimented into the cluster core within the Hubble time. We demonstrate the scenario using the NFW profile as th

Yu. Zadorozhny, Y. Liu

Resistance of disordered superconducting Au$_{0.7}$In$_{0.3}$ cylindrical films was measured as a function of applied magnetic field. In the high-temperature part of the superconducting transition regime, the resistance oscillated with a period of $h/2e$ in the unit of the enclosed magnetic flux. However, at lower temperatures, the resistance peaks split. We

Massimo Ricotti, J. Michael Shull

Several observational and theoretical arguments suggest that starburst galaxies may rival quasars as sources of metagalactic ionizing radiation at redshifts z > 3. Reionization of the intergalactic medium (IGM) at z > 5 may arise, in part, from the first luminous massive stars. To be an important source of radiative feedback from star formation, a substantia

L. F. Santos, C. O. Escobar

This paper presents arguments purporting to show that von Neumann&#39;s description of the measurement process in quantum mechanics has a modern day version in the decoherence approach. We claim that this approach and the de Broglie-Bohm theory emerges from Bohr&#39;s interpretation and are therefore obliged to deal with some obscures ideas which were anteci

C. M. Bowden, S. D. Pethel

A scenario for realization of a quantum computer is proposed consisting of spatially distributed q-bits fabricated in a host structure where nuclear spin-spin coupling is mediated by laser pulse controlled electron-nuclear transferred hyperfine (superhyperfine) Fermi contact interaction. Operations illustrating entanglement, nonlocality, and quantum control

Daniel R. Terno

The arguments of Cohen [Phys. Rev. A {\bf 60}, 80 (1999)] against the `ignorance interpretation&#39; of mixed states are questioned. The physical arguments are shown to be inconsistent and the supporting example illustrates the opposite of the original statement. The operational difference between two possible definitions of mixed states is exposed and the i

Guy Potvin

An interpretation of quantum mechanics is proposed which augments the stochastic pilot-wave model, introduced by Nelson [E. Nelson, Phys. Rev., 150, 1079 (1966)], with a dual guidance condition. Namely, in addition to the stochastic guidance condition which describes how the wave controls the particle (wave-to-particle guidance condition), we introduce anoth

L. Khaykovich, N. Friedman, S. Baluschev, D. Fathi

We propose a new spectroscopic method for measuring weak transitions in cold and trapped atoms, which exploits the long interaction times and tight confinement offered by dark optical traps together with an electron shelving technique to achieve extremely high sensitivity. We demonstrate our scheme by measuring a 5S_{1/2}-> 5D_{5/2} two-photon transition in

Johan N. Malmberg, Andreas H. Carlsson, Dan Anderson, Mietek Lisak

We address the problem of existence and stability of vector spatial solitons formed by two incoherently interacting optical beams in bulk Kerr and saturable media. We identify families of (2+1)-dimensional two-mode self-trapped beams, with and without a topological charge, and describe their properties analytically and numerically.

H. Heiselberg

Recent developments in neutron star theory and observation are discussed. Based on modern nucleon-nucleon potentials more reliable equations of state for dense nuclear matter have been constructed. Furthermore, phase transitions such as pion, kaon and hyperon condensation, superfluidity and quark matter can occur in cores of neutron stars. Specifically, the

Karl Rubin, Alice Silverberg

We show that the unboundedness of the ranks of the quadratic twists of an elliptic curve is equivalent to the divergence of certain infinite series.

Siddhartha Bhattacharya

Suppose $X_{1}, X_{2}$ are nilmanifolds and $ρ, σ$ are automorphism actions of a discrete group $Γ$ on $X_{1}$ and $X_{2}$ respectively. We show that if $(X_{1},ρ)$ and $(X_{2}, σ)$ satisfy certain additional conditions then every $Γ$-equivariant continuous map from $(X_{1},ρ)$ to $(X_{2},σ)$ is an affine map.

Pavel Etingof, Travis Schedler, Olivier Schiffmann

We provide an explicit quantization of dynamical r-matrices for semisimple Lie algebras, classified earlier by the third author, which includes the Belavin-Drinfeld r-matrices. We do so by constructing an appropriate (dynamical) twist in the tensor square of the Drinfeld-Jimbo quantum group U_q(g), which twists the R-matrix of U_q(g) into the desired quatiza

P. A. Ferrari, A. Galves, C. Landim

We give bounds on the rate of convergence to equilibrium of the symmetric simple exclusion process in $\Z^d$. Our results include the existent results in the literature. We get better bounds and larger class of initial states via a unified approach. The method includes a comparison of the evolution of n interacting particles with n independent ones along the

Lionel Rosier, Eduardo D. Sontag

This paper deals with the regularity of solutions of the Hamilton-Jacobi Inequality which arises in H-infinity control. It shows by explicit counterexamples that there are gaps between existence of continuous and locally Lipschitz (positive definite and proper) solutions, and between Lipschitz and continuously differentiable ones. On the other hand, it is sh

Aidan Schofield

The depth of a vector bundle E over the projective plane P^2 is the largest integer h such that [E]/h is in the Grothendieck group of coherent sheaves on P^2 where [E] is the class of E in this Grothendieck group. We show that a moduli space of vector bundles is birational to a suitable number of h by h matrices up to simultaneous conjugacy where h is the de

Alexander O. Prishlyak

We consider functions with isolated critical points on a closed surface. We prove that in a neighborhood of a critical point the function conjugates with Re$z^k$ for the some nonnegative integer k. The full topological invariant of such functions is constructed.

Tomas L. Gomez, T. R. Ramadas

Let X be as smooth complex projective variety with Neron-Severi group isomorphic to Z, and D an irreducible divisor with normal crossing singularities. Assume r is equal to 2 or 3. We prove that if the fundamental group of X doesn&#39;t have irreducible PU(r) representations, then the fundamental group of X-D doesn&#39;t have irreducible U(r) representations

Terence Tao

We prove the converse of Yano&#39;s extrapolation theorem for translation invariant operators.

Imre Tuba

We characterize all simple unitarizable representations of the braid group $B_3$ on complex vector spaces of dimension $d \leq 5$. In particular, we prove that if $σ_1$ and $σ_2$ denote the two generating twists of $B_3$, then a simple representation $ρ:B_3 \to \gl(V)$ (for $\dim V \leq 5$) is unitarizable if and only if the eigenvalues $λ_1, λ_2, ..., λ_d$

David Goss

We propose analogs of the classical Generalized Riemann Hypothesis and the Generalized Simplicity Conjecture for the characteristic p L-series associated to function fields over a finite field. These analogs are based on the use of absolute values. Further we use absolute values to give similar reformulations of the classical conjectures (with, perhaps, fini

Masafumi Fukuma, Takeshi Oota, Hirokazu Tanaka

The system of D1 and D5 branes with a Kaluza-Klein momentum is re-investigated using the five-dimensional U-duality group E_{6(+6)}(Z). We show that the residual U-duality symmetry that keeps this D1-D5-KK system intact is generically given by a lift of the Weyl group of F_{4(+4)}, embedded as a finite subgroup in E_{6(+6)}(Z). We also show that the residual

Bert Schroer

Recent progress on a constructive approach to QFT which is based on modular theory is reviewed and compared with the standard quantization approaches. Talk given at ``Quantum Theory and Symmetries&#39;&#39;, Goslar, Germany, July 1999

Morten Nielsen, N. K. Nielsen

Instantons in massless theories do not carry over to massive theories due to Derrick&#39;s theorem. This theorem can, however, be circumvented, if a constraint that restricts the scale of the instanton is imposed on the theory. Constrained instantons are considered in four dimensions in phi^4 theory and SU(2) Yang-Mills-Higgs theory. In each of these theorie

Tom Weidig

We show how to calculate the quantum mass correction to (1+1)D solitonic field theories using numerical methods. This is essential if we want to find the corrections to non-integrable models. We start with a review of the standard derivation of the first order quantum correction. Then, we re-derive a trace formula which allows us to compute the mass correcti

V. I. Ritus

The action changes (and thus the vacuum conservation amplitudes) in the proper-time representation are found for an accelerated mirror interacting with scalar and spinor vacuum fields in 1+1 space. They are shown to coincide to within the multiplier e^2 with the action changes of electric and scalar charges accelerated in 3+1 space. This coincidence is attri

Martijn Wijnholt, Slava Zhukov

We examine the attractor mechanism for extremal black holes in the context of five dimensional N = 2 supergravity and show that attractor points are unique in the extended vector multiplet moduli space. Implications for black hole entropy are discussed.

Charles Gale, Sangyong Jeon, Joseph Kapusta

Using a coherence time extracted from high precision proton-nucleus Drell-Yan measurements and a nuclear absorption cross section extracted from pA charmonium production experiments, we study J/psi production and absorption in nucleus-nucleus collisions. We find that coherence time effects are large enough to affect the measured J/psi-to-Drell-Yan ratio. The

Carlo Giunti

We consider the two four-neutrino schemes that are compatible with all neutrino oscillation data. We present the range of the corresponding mixing parameters allowed by the results of neutrino oscillation experiments. We discuss the implications for long-baseline experiments and we suggest the possibility to reveal the presence of CP-violating phases through

Eung Jin Chun, Stefan Pokorski

It is pointed out that important contribution to neutrino masses and mixing can come from flavour violating slepton exchange. For low and intermediate $\tanβ$ such effects can dominate over the usual tau Yukawa coupling effects included in the renormalization group evolution. The mixing angles satisfy then the relation different from the fixed point solution

Peter Arnold

A Langevin equation with multiplicative noise is an equation schematically of the form dq/dt = - F(q) + e(q) xi, where e(q) xi is Gaussian white noise whose amplitude e(q) depends on q itself. I show how to convert such equations into path integrals. The definition of the path integral depends crucially on the convention used for discretizing time, and I spe

Mairi Sakellariadou

Within a string cosmology context, the large scale temperature anisotropies may arise from the contribution of seeds to the metric fluctuations. We study the cases of electromagnetic and axion seeds. We find that massless or very light axions can lead to a flat or slightly tilted blue spectrum, that fits current data.

Carlo Oleari

We present some results on renormalization and factorization scale dependence of soft-gluon resummation, at the next-to-leading-logarithmic level, in the fixed-target hadro-production cross-section for prompt photons.

D. S. Isert, S. P. Klevansky

The non-equilibrium two loop self-energy is reexamined in the framework of a scalar quark and gluon model, with specific attention to terms which do not give rise to the standard two -> two particle collisional terms in the semi-classical Boltzmann equation. It is shown that most of these terms contribute to renormalization of component lines at a lower leve

A. A. Arkhipov

The fundamental relation between the slopes of diffraction cone in single diffraction dissociation and elastic scattering has been derived.

Dongsheng Du, Deshan Yang, Guohuai Zhu

Di-gluon fusion mechanism might account for the large branching ratios of $B\to K η^{\prime}$. But because we know little about the effective $η^{\prime}gg$ vertex, there are large uncertainties in perturbative QCD estimations. In this paper, we try several kinds of $η^{\prime}gg$ form factors and compare the numerical results with the experiment. We find th

N. Sakai

Supersymmetric theories are reviewed in the context of field theories. The gauge hierarchy problem in attempting the unification of all fundamental interactions is the strongest motivation of modern development of supersymmetry. Starting from the general notion of supersymmetry as a symmetry between bosons and fermions, we explain how the supersymmetry becom

Seyong Kim, Shigemi Ohta

Without chiral extrapolation, we achieved a realistic nucleon to (ρ)-meson mass ratio of (m_N/m_ρ= 1.23 \pm 0.04 ({\rm statistical}) \pm 0.02 ({\rm systematic})) in our quenched lattice QCD numerical calculation with staggered quarks. The systematic error is mostly from finite-volume effect and the finite-spacing effect is negligible. The flavor symmetry bre

E. M. Aitala

We present the results of a five-dimensional resonant amplitude analysis of the $Λ_c^+{\to}pK^{-}π^{+}$ system based on $946\pm 38$ reconstructed decays. These data were produced in 500 GeV/$c$ $π^-$-N interactions by Fermilab experiment E791. We report measurements of the amplitudes for $Λ_c^+$ decay into nonresonant $pK^-π^+$ and to $p\bar{K}^{*0}(890)$, $

D. Bortoletto

Since the first observation in 1964, CP violation remains one of the most elusive aspects of the standard model. The CDF collaboration has reported the first evidence of CP violation in the B system using the world&#39;s largest sample of $B \to J/ψK^0_S $ decays. The direct measurement of sin$(2β)$=0.79$^{+0.41}_{-0.44}$ (combined statistical and systematic

Yurij V. Baryshev

A retrospective analysis of the field theory of gravitation, describing gravitational field in the same way as other fields of matter in the flat space-time, is done. The field approach could be called &#34;quantum gravidynamics&#34; to distinguish it from the &#34;geometrodynamics&#34; or general relativity. The basic propositions and main conclusions of th

Daisuke Ida

A simple model of the brane-world cosmology has been proposed, which is characterized by four parameters, the bulk cosmological constant, the spatial curvature of the universe, the radiation strength arising from bulk space-time and the breaking parameter of $Z_2$-symmetry. The bulk space-time is assumed to be locally static five-dimensional analogue of the

W C Lim, U S Nilsson, J Wainwright

We show the existence of spatially homogeneous but anisotropic cosmological models whose cosmic microwave background temperature is exactly isotropic at one instant of time but whose rate of expansion is highly anisotropic. The existence of these models shows that the observation of a highly isotropic cosmic microwave background temperature cannot alone be u

Gabriel Istrate

Let c>0 be a constant, and $Φ$ be a random Horn formula with n variables and $m=c\cdot 2^{n}$ clauses, chosen uniformly at random (with repetition) from the set of all nonempty Horn clauses in the given variables. By analyzing \PUR, a natural implementation of positive unit resolution, we show that $\lim_{n\goesto \infty} \PR ({$Φ$ is satisfiable})= 1-F(e^{-

Joseph Y. Halpern

The assumptions needed to prove Cox&#39;s Theorem are discussed and examined. Various sets of assumptions under which a Cox-style theorem can be proved are provided, although all are rather strong and, arguably, not natural.

C. A. Büsser, E. V. Anda, A. L Lima, Maria A. Davidovich

The interplay between the Kondo effect and the inter-dot magnetic interaction in a coupled-dot system is studied. An exact result for the transport properties at zero temperature is obtained by diagonalizing a cluster, composed by the double-dot and its vicinity, which is connected to leads. It is shown that the system goes continuously from the Kondo regime