January 1999 arXiv papers — page 5

A. Cuccoli, A. Fubini, V. Tognetti, R. Vaia

We consider quantum nonlinear many-body systems with dissipation described within the Caldeira-Leggett model, i.e., by a nonlocal action in the path integral for the density matrix. Approximate classical-like formulas for thermodynamic quantities are derived for the case of many degrees of freedom, with general kinetic and dissipative quadratic forms. The un

Kanehisa Takasaki

Gorsky et al. presented an explicit construction of Whitham deformations of the Seiberg-Witten curve for the $SU(N+1)$ $\calN = 2$ SUSY Yang-Mills theory. We extend their result to all classical gauge groups and some other cases such as the spectral curve of the $A^{(2)}_{2N}$ affine Toda Toda system. Our construction, too, uses fractional powers of the supe

J. S. B. Wyithe, R. L. Webster, E. L. Turner

Determination of microlensing parameters in the gravitationally lensed quasar Q2237+0305 from the statistics of high magnification events will require monitoring for more than 100 years (Wambsganss, Paczynski & Schneider 1990). However we show that the effective transverse velocity of the lensing galaxy can be determined on a more realistic time-scale throug

Debra J. Searles, Denis J. Evans

The Fluctuation Theorem describes the probability ratio of observing trajectories that satisfy or violate the second law of thermodynamics. It has been proved in a number of different ways for thermostatted deterministic nonequilibrium systems. In the present paper we show that the Fluctuation Theorem is also valid for a class of stochastic nonequilibrium sy

Y. P. Jing

We study the diversity of the density profiles of dark matter halos based on a large set of high-resolution cosmological simulations of 256^3 particles. The cosmological models include four scale-free models and three representative cold dark matter models. The simulations have good force resolution, and there are about 400 massive halos with more than 10^4

J. S. B. Wyithe, R. L. Webster, E. L. Turner

We present a method for computing the probability distribution of microlensed light curve derivatives both in the case of a static lens with a transverse velocity, and in the case of microlensing that is produced through stellar proper motions. The distributions are closely related in form, and can be considered equivalent after appropriate scaling of the in

Konrad Banaszek

A setup for discriminating between arbitrary two coherent states of a single light mode with the highest success rate allowed by quantum mechanics is presented. Its application to time-multiplexed quantum key distribution is discussed.

Juergen Audretsch, Vladimir Skarzhinsky

The Aharonov-Bohm scattering of charged particles by the magnetic field of an infinitely long and infinitely thin solenoid (magnetic string) in an absorbing medium is studied. We discuss the partial-wave approach to this problem and show that standard partial-wave method can be adjusted to this case. The effect of absorption leads to oscillations of the AB c

D. Home, A. S. Majumdar

We argue that the inference of CP violation in experiments involving the $K^0-\bar{K^0}$ system in weak interactions of particle physics is facilitated by the assumption of particle trajectories for the decaying particles and the decay products. A consistent explanation in terms of such trajectories is naturally incorporated within the Bohmian interpretation

Konrad Banaszek

I present a novel algorithm for reconstructing the Wigner function from homodyne statistics. The proposed method, based on maximum-likelihood estimation, is capable of compensating for detection losses in a numerically stable way.

Lawrence R. Pratt, Shekhar Garde, Gerhard Hummer

Recent progress on molecular theories of hydration of nonpolar solutes in aqueous solution has led to new ways of thinking about the old issue of free, or "available," volume in liquids. This article surveys the principal new results with particular attention to general issues of packing in liquids.

H. Witala, W. Gloeckle

A study of 3-body resonances has been performed in the framework of configuration space Faddeev equations. The importance of keeping a sufficient number of terms in the asymptotic expansion of the resonance wave function is pointed out. We investigated three neutrons interacting in selected force components taken from realistic nn forces.

K. A. Van Riper, S. G. Mashnik, W. B. Wilson

Methods for radionuclide production calculation in a high power proton accelerator have been developed and applied to study production of 22 isotopes by high-energy protons and neutrons. These methods are readily applicable to accelerator, and reactor, environments other than the particular model we considered and to the production of other radioactive and s

V. M. Kolybasov

It is shown that nonzero orbital momentum in the vertex of secondary interaction in the triangle graph leads to a more clear picture corresponding to the moving complex singularity compared with the case of constant vertex. The peak in the distribution of the final particles invariant mass becomes narrower and its shift with momentum transfer more distinct.

L. Erdos, H. -T. Yau

We study the time evolution of a quantum particle in a Gaussian random environment. We show that in the weak coupling limit the Wigner distribution of the wave function converges to a solution of a linear Boltzmann equation globally in time. The Boltzmann collision kernel is given by the Born approximation of the quantum differential scattering cross section

M. Olshanetsky

In this survey we present the interpretation of isomondromy preserving equations on Riemann surfaces with marked points as reduced Hamiltonian systems. The upstairs space is the space of smooth connections of GL(N) bundles with simple poles in the marked points. We discuss relations of these equations with the Whitham quantization of the Hitchin systems and

Giovanni Felder, Alexander Varchenko

Conformal blocks for the WZW model on tori can be represented by vector valued Weyl anti-symmetric theta functions on the Cartan subalgebra satisfying vanishing conditions on root hyperplanes. We introduce a quantum version of these vanishing conditions in the sl(2) case. They are compatible with the qKZB equations and are obeyed by the hypergeometric soluti

Weiping Li

In this paper, we compute the symplectic Floer homology of the figure eight knot. This provides first nontrivial knot with trivial symplectic Floer homology.

Joel David Hamkins

The landmark Levy-Solovay Theorem limits the kind of large cardinal embeddings that can exist in a small forcing extension. Here I announce a generalization of this theorem to a broad new class of forcing notions. One consequence is that many of the forcing iterations most commonly found in the large cardinal literature create no new weakly compact cardinals

Robert Myers

An uncountable collection of arcs in S^3 is constructed, each member of which is wild precisely at its endpoints, such that the fundamental groups of their complements are non-trivial, pairwise non-isomorphic, and indecomposable with respect to free products. The fundamental group of the complement of a certain Fox-Artin arc is also shown to be indecomposabl

Joel David Hamkins

Many of the most common reverse Easton iterations found in the large cardinal context, such as the Laver preparation, admit a gap at some small delta in the sense that they factor as P*Q, where P has size less than delta and Q is forced to be delta-strategically closed. In this paper, generalizing the Levy-Solovay theorem, I show that after such forcing, eve

A. Gregori, C. Kounnas, J. Rizos

Using free world-sheet fermions, we construct and classify all the N=2, Z2 X Z2 four-dimensional orbifolds of the type IIA/B strings for which the orbifold projections act symmetrically on the left and right movers. We study the deformations of these models out of the fermionic point, deriving the partition functions at a generic point in the moduli of the i

Peter van Nieuwenhuizen, Shin'ichi Nojiri, Sergei D. Odintsov

We study quantum dilaton coupled spinors in two and four dimensions. Making classical transformation of metric, dilaton coupled spinor theory is transformed to minimal spinor theory with another metric and in case of 4d spinor also in the background of the non-trivial vector field. This gives the possibility to calculate 2d and 4d dilaton dependent conformal

A. Gregori, C. Kounnas, P. M. Petropoulos

The non-perturbative equivalence of four-dimensional N=2 superstrings with three vector multiplets and four hypermultiplets is analysed. These models are obtained through freely acting orbifold compactifications from the heterotic, the symmetric and the asymmetric type II strings. The heterotic scalar manifolds are (SU(1,1) / U(1))^3 for the S,T,U moduli sit

Fabio Riccioni, Augusto Sagnotti

We review some properties of the field equations of six-dimensional (1,0) supergravity coupled to tensor and vector multiplets, and in particular their relation to covariant and consistent anomalies and a peculiar Noether identity for the energy-momentum tensor. We also describe a lagrangian formulation for this system, obtained applying the Pasti-Sorokin-To

Ernest Ma, Martti Raidal, Utpal Sarkar

In the supersymmetric standard model of particle interactions, R-parity nonconservation is often invoked to obtain nonzero neutrino masses. We point out here that such interactions of the supersymmetric particles would erase any pre-existing lepton or baryon asymmetry of the universe before the electroweak phase transition through the $B + L$ violating sphal

P. Keranen, J. Maalampi, J. T. Peltoniemi

Active galactic nuclei and gamma ray bursts at cosmological distances are sources of high-energy electron and muon neutrinos and provide a unique test bench for neutrino instability. The typical lifetime-to-mass ratio one can reach there is $τ/m\sim 500 Mpc/cE_ν\sim 500$ s/eV. We study the rapid decay channel $ν_i\toν_j+ϕ$, where $ϕ$ is a massless or very li

J. Fleischer, O. L. Veretin

Methods developed by the Bielefeld-DESY-Dubna collaboration in recent years are: DIANA (DIagram ANAlyser), a program to produce ``FORM input'' for Feynman diagrams, starting from the Feynman rules; methods to calculate scalar diagrams: Taylor expansion in small momenta squared in connection with a mapping and the Padé method to sum the series. Recent

Debasish Majumdar, Amitava Raychaudhuri

The SuperKamiokande collaboration has presented results on the observation of solar neutrinos. The Sudbury Neutrino Observatory (SNO) is also expected to go on-line in the near future. We propose several new variables, insensitive to the absolute flux of the initial solar neutrino beam, which probe the shape of the observed spectrum at these experiments and

C. Deffayet

Local cosmic strings solutions are introduced in a model with a pseudo-anomalous U(1) gauge symmetry. Such a symmetry is present in many superstring compactification models. The coupling of those strings with the axion necessary in order to cancel the anomalies does not prevent them from being local, even though their energy per unit length is found to diver

Harry J. Lipkin

Why Hand Waving? All calculations in books describe oscillations in time. But real experiments don't measure time. Hand waving is used to convert the results of a "gedanken time experiment" to the result of a real experiment measuring oscillations in space. Right hand waving gives the right answer; wrong hand waving gives the wrong answer. Many p

N. V. Krasnikov

We show that the search for supersymmetry at LHC will be very problematic for the particular case of nonuniversal relations among gaugino masses. Namely, if gluino, first chargino and LSP masses are closed to each other it would be very difficult to discover supersymmetry even if sparticle masses are lighter than 1 TeV.

Carl R. Schmidt

Recent concerns about the very large next-to-leading logarithmic (NLL) corrections to the BFKL equation are addressed by the introduction of a physical rapidity-separation parameter $Δ$. At the leading logarithm (LL) this parameter enforces the constraint that successive emitted gluons have a minimum separation in rapidity, $y_{i+1}-y_i>Δ$. The most signific

Aiichi Iwazaki

Axions are possible candidates of dark matter in the present Universe. They have been argued to form axionic boson stars with small masses $10^{-14}M_{\odot}\sim 10^{-11}M_{\odot}$. Since they possess oscillating electric fields in a magnetic field, they dissipate their energies in magnetized conducting media such as white dwarfs or neutron stars. At the sam

JLQCD Collaboration, S. Aoki, M. Fukugita, S. Hashimoto

We report results of quark masses in quenched lattice QCD with the Kogut-Susskind fermion action, employing the Reguralization Independent scheme (RI) of Martinelli et al. to non-perturbatively evaluate the renormalization factor relating the bare quark mass on the lattice to that in the continuum. Calculations are carried out at β=6.0, 6.2, and 6.4, from wh

S. Amendola, E. Barbuto, C. Bozza, C. D'Apolito

A report on the analysis work in the Salerno Emulsion Laboratory is presented. It is related to the search for nu_mu->nu_tau oscillations in CHORUS experiment, the calibrations in the WANF (West Area Neutrino Facility) at Cern and tests and preparation for new experiments.

S. Amendola, E. Barbuto, C. Bozza, C. D'Apolito

SySal (SYstem of SALerno) is the automatic scanning system developed in the emulsion laboratory of Salerno to take part in the emulsion scanning phase of the CHORUS experiment at CERN. In the following chapters we will present features, results and further developments of this automatic multi-tracking system.

K. D. Kokkotas, T. A. Apostolatos, N. Andersson

We study the problem of detecting, and infering astrophysical information from, gravitational waves from a pulsating neutron star. We show that the fluid f and p-modes, as well as the gravitational-wave w-modes may be detectable from sources in our own galaxy, and investigate how accurately the frequencies and damping rates of these modes can be infered from

Adrian P. Gentle

Regge calculus is used to construct initial data for vacuum axisymmetric Brill waves at a moment of time symmetry. We argue that only a tetrahedral lattice can successfully reproduce the continuum solution, and develop a simplicial axisymmetric lattice based on the co-ordinate structure of the continuum metric. This is used to construct initial data for Bril

E. R. Bezerra de Mello, V. B. Bezerra, N. R. Khusnutdinov

We consider the ground state energy of scalar massive field in the spacetime of a pointlike global monopole. Using zeta function regularization method we obtain the heat kernel coefficients for this system. We show that the coefficient $B_1$ contains additional contribution due to the non-trivial topological structure of the spacetime. Taking into account th

S. Hollands

In this paper we propose a definition of quasifree Hadamard states for spinor fields on a curved space-time by specifying the Polarisation Set of the two-point function. We prove that the thermal equilibrium state on an ultrastatic space-time is Hadamard. We then construct an adiabatic vacuum state on a general globally hyperbolic Lorentz manifold using a fa

L. Lusanna

After a review of the canonical reduction to the rest-frame Wigner-covariant instant form of standard theories in Minkowski spacetime, a new formulation of tetrad gravity is introduced. Its canonical reduction, also in presence of N scalar particles, is done. The modification of the ADM formulation to solve the deparametrization problem of general relativity

Pawel Cholewinski, Miroslaw Truszczynski

We study the following problem: given a class of logic programs C, determine the maximum number of stable models of a program from C. We establish the maximum for the class of all logic programs with at most n clauses, and for the class of all logic programs of size at most n. We also characterize the programs for which the maxima are attained. We obtain sim

V. J. Emery, S. A. Kivelson, V. N. Muthukumar

The phenomenology of charge transport in synthetic metals is reviewed. It is argued that the conventional quasiparticle picture and Boltzmann transport theory do not apply to these materials. The central ideas of Fermi liquid theory are reviewed, and the significant corrections produced by quasiparticle scattering from ferromagnetic spin fluctuations in liqu

S. Nechaev, G. Oshanin, A. Blumen

We study dynamics of a Rouse polymer chain, which diffuses in a three-dimensional space under the constraint that one of its ends, referred to as the slip-link, may move only along a one-dimensional line containing randomly placed, immobile, perfect traps. For such a model we compute exactly the time evolution of the probability $P_{sl}(t)$ that the chain sl

A. Johansen, D. Sornette

We propose that imitation between traders and their herding behaviour not only lead to speculative bubbles with accelerating over-valuations of financial markets possibly followed by crashes, but also to ``anti-bubbles'' with decelerating market devaluations following all-time highs. For this, we propose a simple market dynamics model in which the de

R. M. L. Evans, M. E. Cates, P. Sollich

We study self-diffusion within a simple hopping model for glassy materials. (The model is Bouchaud's model of glasses [J.-P. Bouchaud, J. Physique I 2, 1705 (1992)], as extended to describe rheological properties [P. Sollich, F. Lequeux, P. Hebraud and M.E. Cates, Phys. Rev. Lett. 78, 2020 (1997)].) We investigate the breakdown, near the glass transition

H. Kjønsberg, J. M. Leinaas

We present Monte Carlo studies of charge expectation values and charge fluctuations for quasi-particles in the quantum Hall system. We have studied the Laughlin wave functions for quasi-hole and quasi-electron, and also Jain's definition of the quasi-electron wave function. The considered systems consist of from 50 to 200 electrons, and the filling fract

M. Heerema, W. A. van Leeuwen

On the basis of the general form for the energy needed to adapt the connection strengths of a network in which learning takes place, a local learning rule is found for the changes of the weights. This biologically realizable learning rule turns out to comply with Hebb's neuro-physiological postulate, but is not of the form of any of the learning rules pr

S. Sergeenkov, H. Bougrine, M. Ausloos, R. Cloots

Nearly a 50% decrease of resistivity ρ(T,x) due to just 4% Cu doping on the Mn site of La(2/3)Ca(1/3)Mn(1-x)Cu(x)O(3) is observed. Attributing the observed phenomenon to the substitution induced decrease of the spin polaron energy E_s(x) below the Curie point T_C(x)=T_C(0)(1-x), all data are found to be well fitted by the nonthermal coherent tunneling expres

A. Weisse, G. Wellein, H. Fehske

As a simple model for spin-Peierls systems we study a frustrated Heisenberg chain coupled to optical phonons. In view of the anorganic spin-Peierls compound CuGeO3 we consider two different mechanisms of spin-phonon coupling. Combining variational concepts in the adiabatic regime and perturbation theory in the anti-adiabatic regime we derive effective spin H

C. Stadler, F. Schmid

Constant pressure Monte Carlo simulations of a coarse grained off-lattice model for monolayers of amphiphilic molecules at the air/water interface are presented. Our study focusses on phase transitions within a monolayer rather than on self aggregation. We thus model the molecules as stiff chains of Lennard-Jones spheres with one slightly larger repulsive en

Sanjay Puri, Hisao Hayakawa

We formulate a phenomenological model for the segregation of binary mixtures of rough and smooth granular materials in a rotating drum. Our model successfully replicates a range of experimental behaviours, e.g., rapid radial segregation; slow axial segregation; and nonuniform radial structure of axial bands. We present some analytical results and detailed nu

Stephen W. Pierson, Oriol T. Valls

Vortices in a thin-film superconductor interact logarithmically out to a distance on the order of the two-dimensional (2D) magnetic penetration depth $λ_\perp$, at which point the interaction approaches a constant. Thus, because of the finite $λ_\perp$, the system exhibits what amounts to an {\it intrinsic} finite size effect. It is not described by the 2D C

Eric Lewin Altschuler, Martin Lades

Sulfur has recently been found to be a superconductor at high pressure. At ~93 GPa Tc is 10.1 K, and the sulfur is in a base-centered orthorhombic (b.c.o) structure. At ~160 GPa Tc is 17 K and sulfur is in a rhobohedral (b-Po) structure. The mechanism for superconductivity in sulfur is not known; in particular, a band-structure calculation does not find supe

Gary Ayton, Denis J. Evans, Debra J. Searles

The Fluctuation Theorem (FT) gives an analytic expression for the probability, in a nonequilibrium system of finite size observed for a finite time, that the dissipative flux will flow in the reverse direction to that required by the Second Law of Thermodynamics. In the present letter a Local version of the Fluctuation Theorem (LFT), is derived. We find that

C. T. Rieck, D. Straub, K. Scharnberg

The low temperature surface resistance R_s of d-wave superconductors is calculated as function of frequency assuming normal state quasiparticle mean free paths l in excess of the penetration depth. Results depend strongly on the geometric configuration. In the clean limit, two contributions to R_s with different temperature dependencies are identified: photo

R. O. Grigoriev

In a recent paper [Phys. Rev. E 57, p. 1550 (1998)] we demonstrated that the symmetries of the evolution equation and the target state have a profound effect on the selection of the admissible control parameters. In the present paper we extend these results to the case of time-periodic target states and inexact symmetries. We also argue that the problem of p

Eric P. Rubenstein, Charles D. Bailyn

We consider the effect of binary stars on the main-sequence luminosity functions observed in the core of globular clusters, with specific reference to NGC 6752. We find that mass segregation results in an increased binary fraction at fainter magnitudes along the main-sequence. If this effect is not taken into account when analyzing luminosity functions, erro

Frank Krennrich

High energy gamma-ray astronomy has been established during the last decade through the launch of the Compton Gamma Ray Observatory (CGRO) and the success of its ground-based counterpart, the imaging atmospheric Cherenkov technique. In the aftermath of their important and surprising scientific results a worldwide effort developing and designing new generatio

W. N. Brandt, Th. Boller, A. C. Fabian, M. Ruszkowski

We report results from an 18-day ROSAT HRI monitoring campaign on the ultrasoft Narrow-Line Seyfert 1 (NLS1) class quasar PHL 1092. This luminous, radio-quiet quasar showed strong X-ray variability in a short ROSAT PSPC observation, and ROSAT HRI monitoring of the similar object IRAS 13224-3809 revealed extreme variability on intermediate timescales. We want

M. Cervino, J. M. Mas-Hesse

We present in this contribution the predictions on the multiwavelength spectral energy distribution of our evolutionary population synthesis models including single and binary stellar systems. The high energy computations include the emission associated to X-ray binaries and supernovae remnants, as well as the mechanical energy released into the interstellar

H. Tadros, W. E. Ballinger, A. N. Taylor, A. F. Heavens

We apply the formalism of spherical harmonic decomposition to the galaxy density field of the IRAS PSCz redshift survey. The PSCz redshift survey has almost all-sky coverage and includes IRAS galaxies to a flux limit of 0.6 Jy. Using maximum likelihood methods to examine (to first order) the distortion of the galaxy pattern due to redshift coordinates, we ha

J. M. Mas-Hesse, M. Cervino

We present in this contribution our set of multiwavelength synthesis models including the evolution of single and binary stars. The main results we have obtained can be summarized as follows: (a) massive close-binary systems will start to experience mass transfer episodes after the first 4 Myr of the starburst evolution; (b) as a result of these mass transfe

Philip Kaaret, Santina Piraino, Eric C. Ford, Andrea Santangelo

Exploiting the presence of kilohertz quasi-periodic oscillations (QPOs) in the timing power spectrum, we find that the soft x-ray emission of the neutron-star X-ray binary and atoll source 4U1636-536 modulated at the QPO frequency lags behind that of the hard x-ray emission. Emission in the 3.8-6.4 keV band is delayed by 25.0 +/- 3.3 microseconds relative to

P. Lira, A. Lawrence, P. O'Brien, R. A. Johnson

We report the detection of optical and X-ray variability in the least luminous known Seyfert galaxy, NGC4395. The featureless continuum changed by a factor of 2 in 6 months, which is typical of more luminous AGN. The largest variation was seen at shorter wavelengths, so that the spectrum becomes `harder' during higher activity states. In a one week optic

O. Petruk

The results of the 2D modelling of Supernova remnant (SNR) RCW86 are given. Models of this remnant, which for the first time interpret the anisotropy of surface brightness as a result of the evolution of adiabatic SNR in the interstellar medium with a large-scale gradient of density, are considered. Estimations on the basic characteristics of RCW86 and the s

Padeli P. Papadopoulos, E. R. Seaquist

We report on sensitive sub-mm imaging observations of the prototype Seyfert~2/starburst galaxy NGC 1068 at 850 $μ$m and 450 $μ$m using the Submillimetre Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT). We find clear evidence of dust emission associated with the extended HI component which together with the very faint $ ^{12}$C

S. Benetti, M. Turatto, E. Cappellaro, I. J. Danziger

Observations of the type II SN 1996L reveal the presence of a slowly expanding (V~700$ km/s) shell at ~ 10^(16) cm from the exploding star. Narrow emission features are visible in the early spectra superposed on the normal SN spectrum. Within about two months these features develop narrow symmetric P-Cygni profiles. About 100 days after the explosion the lig

L. Morales-Rueda, M. D. Still, P. Roche

GK Persei is an intermediate polar that exhibits a dwarf nova outburst approximately every 1000 days. During previous outbursts the system has displayed kilo-second quasi-periodic oscillations (QPOs) in X-ray emission. These oscillations are unique in that they are an order of magnitude longer than QPOs usually observed in disc-fed cataclysmic variables. We

F. Daigne, R. Mochkovitch

BeppoSAX observations of the single pulse burst GRB960720 have allowed a detailed study of its X-ray properties: pulse width in different energy bands, spectral evolution from 2 to 700 keV, etc. We show that the early (0-5s) X-ray emission and the gamma-rays are well explained by internal shocks in a relativistic wind while the late (5-20s) X-ray emission co

D. E. Innes, G. Toth

Small-scale explosive events or microflares occur throughout the chromospheric network of the Sun. They are seen as sudden bursts of highly Doppler shifted spectral lines of ions formed at temperatures in the range 2x10^4 - 5x10^5 K. They tend to occur near regions of cancelling photospheric magnetic fields and are thought to be directly associated with magn

Re'em Sari, Tsvi Piran

According to the internal-external shocks model for $γ$-ray bursts (GRBs), the GRB is produced by internal shocks within a relativistic flow while the afterglow is produced by external shocks with the ISM. We explore the early afterglow emission. For short GRBs the peak of the afterglow will be delayed, typically, by few dozens of seconds after the burst. Fo

P. G. Martin

Interstellar dust appears in a number of roles in the interstellar medium. Historically, the most familiar one is as a source of extinction in the optical. Absorbed optical and ultraviolet light heats the dust, whence infrared (including near-infrared to submillimeter) emission, the particular theme of this review. In some distant galaxies, most of the lumin

L. Metcalfe, B. Altieri, B. McBreen, J. -P. Kneib

We present imaging results and source counts from an ISOCAM deep and ultra-deep cosmological survey through gravitationally lensing clusters of galaxies at 7 and 15 microns. A total area of about 53 sq.arcmin was covered in maps of three clusters. The lensing increases the sensitivity of the survey. A large number of luminous mid-infrared (MIR) sources were

D. J. Fixsen, C. L. Bennett, J. C. Mather

The COBE Far InfraRed Absolute Spectrophotometer (FIRAS) observations constitute an unbiased survey over the wavelength range from 100 um to 1 cm over 99% of the sky. Improved calibration of the FIRAS instrument and the inclusion of all of the FIRAS data allow an improved signal to noise determination of the spectral lines by a factor of ~2 over our previous

Ana T. C. Silva, J. F. Fontanari

We study numerically and analytically a stochastic group selection model in which a population of asexually reproducing individuals, each of which can be either altruist or non-altruist, is subdivided into $M$ reproductively isolated groups (demes) of size $N$. The cost associated with being altruistic is modelled by assigning the fitness $1- τ$, with $τ\in

Andrzej Czarnecki, Kirill Melnikov, Alexander Yelkhovsky

We present an analytic calculation of the O(m alpha^6) recoil and radiative recoil corrections to energy levels of positronium nS states and their hyperfine splitting. A complete analytic formula valid to O(m alpha^6) is given for the spectrum of S states. Technical aspects of the calculation are discussed in detail. Theoretical predictions are given for var

Ruben Weht, Warren E. Pickett

We show that Mn_2VAl is a compound for which the generalized gradient approximation (GGA) to the exchange-correlation functional in density functional theory makes a qualitative change in predicted behavior compared to the usual local density approximation (LDA). Application of GGA leads to prediction of Mn_2VAl being a half-metallic ferrimagnet, with the mi

A. N. W. Hone

Recently the associated Camassa-Holm (ACH) equation, related to the Fuchssteiner-Fokas-Camassa-Holm equation by a hodograph transformation, was introduced by Schiff, who derived Bäcklund transformations by a loop group technique and used these to obtain some simple soliton and rational solutions. We show how the ACH equation is related to Schrödinger operato

X. Q. Yuan, Z. Y. Zhang, Y. W. Yu, P. N. Shen

We discuss the structure of Deltaron dibaryon in the chiral SU(3) quark model. The energy of Deltaron is obtained by considering the coupling of the $ΔΔ$ and $CC$ (hidden color) channels. The effects of various parameters on the Deltaron mass are also studied. It is shown that the mass of Deltaron is lower than the mass of $ΔΔ$ but higher than the mass of $Δ

P. N. Shen, Z. Y. Zhang, Y. W. Yu, X. Q. Yuan

The H dihyperon (DH) is studied in the framework of the SU(3) chiral quark model. It is shown that except the $σ$ chiral field, the overall effect of the other SU(3) chiral fields is destructive in forming a stable DH. The resultant mass of DH in a three coupled channel calculation is ranged from 2225 $MeV$ to 2234 $MeV$.

Tomasz Brzezinski

Coalgebra-Galois extensions generalise Hopf-Galois extensions, which can be viewed as non-commutative torsors. In this paper it is analysed when a coalgebra-Galois extension is a separable, split, or strongly separable extension.

Steven Dale Cutkosky

We prove a local theorem on simultaneous resolution of singularities, which is valid in all dimensions. This theorem is proven in dimension 2 (and in all characteristics) by Abhyankar in his book "Ramification theoretic methods in algebraic geometry".

Alexei Zouboff

We prove that the category of faded cosheaves in Set over a sober topological space $(B,Ω)$ is equivalent to a category Sett$(B,Ω)$ having the same class of objects as Set$ / B$ has, but generally a wider class of morphisms. We also prove the converse: if each cosheaf over $T_0$-space $(B,Ω)$ is isomorphic to the cosheaf of tubes of an appropriate map rangin

Z. Fiedorowicz

This paper discusses the question of how to recognize whether an operad is E_n (ie. equivalent to the little n-cubes operad). A construction is given which produces many new examples of E_n operads. This construction is developed in the context of an infinite family of right adjoint constructions for operads. Some other related constructions of E_n operads,

Oleg Andreev

Space-time N=2 and N=4 superconformal algebras can be built using world-sheet free fields or, equivalently, free field representations of osp(1|2) and sl(2|1), respectively. A prescription for the calculation of space-time correlators is given. As applications we compute one and two-point correlation functions of Virasoro (superVirasoro) generators. We also

Igor R. Klebanov

This is a brief introductory review of the AdS/CFT correspondence and of the ideas that led to its formulation. Emphasis is placed on dualities between conformal large $N$ gauge theories in 4 dimensions and string backgrounds of the form $AdS_5\times X_5$. Attempts to generalize this correspondence to asymptotically free theories are also included.

T. M. Aliev, M. Savci

The form factors and the branching ratio of the "B -> a_1 l nu" decay are calculated in framework of QCD sum rules. A comparison of our results on form factors and branching ratio with the results from constituent quark model is presented.

Mairi Sakellariadou

We explore the possibility that a multiple-stage inflationary scenario based on supersymmetric GUT models, can account for the break at $k_b \simeq 0.05 h/Mpc$ in the power spectrum of galaxy clustering, while it reproduces the angular power spectrum of cosmic microwave background anisotropies.

Mikhail Bilenky, German Rodrigo, Arcadi Santamaria

Next-to-leading order calculations for heavy quark three-jet production in e+e- annihilation are reviewed. Their applications for the measurement of the b-quark mass at LEP/SLC and for the test of flavour independence of the strong coupling constant are discussed.

B. Naroska

New results with increased statistics are presented for heavy flavour production at Q2<150 Gev2 and in the photoproduction limit Q2-->0. Cross sections for Dstar production, F2charm, the gluon density in the proton, and inelastic J/psi production are discussed and compared to theoretical calculations. A first measurement of the b anti-b cross section is repo

Laszlo B Szabados

The Ludvigsen-Vickers and two recently suggested quasi-local spin-angular momentum expressions, based on holomorphic and anti-holomorphic spinor fields, are calculated for small spheres of radius $r$ about a point $o$. It is shown that, apart from the sign in the case of anti-holomorphic spinors in non-vacuum, the leading terms of all these expressions coinc

E. I. Guendelman

The possibility of mass in the context of scale-invariant, generally covariant theories, is discussed. The realizations of scale invariance which are considered, are in the context of a gravitational theory where the action, in the first order formalism, is of the form $S = \int L_{1} Φd^4x$ + $\int L_{2}\sqrt{-g}d^4x$ where $Φ$ is a density built out of deg

E. I. Guendelman, Jacov Portnoy

We consider a model of an elementary particle as a 2 + 1 dimensional brane evolving in a 3 + 1 dimensional space. Introducing gauge fields that live in the brane as well as normal surface tension can lead to a stable &#34;elementary particle&#34; configuration. Considering the possibility of non vanishing vacuum energy inside the bubble leads, when gravitati

C. Stephen Hellberg, W. E. Pickett, L. L. Boyer, Harold T. Stokes

Second neighbor dominated exchange coupling in CaV4O9 has been obtained from ab initio density functional (DF) calculations. A DF-based self-consistent atomic deformation model reveals that the nearest neighbor coupling is small due to strong cancellation among the various superexchange processes. Exact diagonalization of the predicted Heisenberg model yield

Hiroshi Imamura, Peter A. Maksym, Hideo Aoki

Ground-state and excited-state properties of vertically coupled double quantum dots are studied by exact diagonalization. Magic-number total angular momenta that minimize the total energy are found to reflect a crossover between electron configurations dominated by intra-layer correlation and ones dominated by inter-layer correlation. The position of the cro

J. S. B. Wyithe, R. L. Webster

The method devised by Lewis et al. (1993) for calculating the light curve of a microlensed point source is expanded to two dimensions to enable the calculation of light curves of extended sources. This method is significantly faster than the ray shooting method that has been used in the past. The increased efficiency is used to obtain much higher resolution

T. Shanks

We update and extend the results of Shanks (1997, MNRAS, 290, L77) by making a direct test of Tully-Fisher distance estimates to thirteen spiral galaxies with HST Cepheid distances and to ten spiral galaxies with Type Ia supernova (SNIa) distances. The results show that the Tully-Fisher distance moduli are too short with respect to the Cepheid distances by 0

T. Shahbaz, F. van der Hooft, J. Casares, P. A. Charles

We have obtained high and intermediate resolution optical spectra of the black-hole candidate Nova Sco 1994 in May/June 1998, when the source was in complete (X-ray) quiescence. We measure the radial velocity curve of the secondary star and obtain a semi-amplitude of K_2=215.5+/-2.4 km/s, which is 6 per cent lower than the only previously determined value. T