September 1999 arXiv papers — page 10

Arkadiusz Jadczyk

We discuss the problem of a degenerate vierbein in the framework of gauge theories of gravitation (thus including torsion). We discuss two examples: Hanson-Regge gravitational instanton and Einstein-Rose bridge.We argue that a region of space-time with vanishing vierbein but smooth principal connection can be, in principle, detected by scattering experiments

Stuart L. Shapiro

Recent numerical simulations address a conjecture by Shapiro that when two neutron stars collide head-on from rest at infinity, sufficient thermal pressure may be generated to support the hot remnant in quasi-static equilibrium against collapse prior to neutrino cooling. The conjecture is meant to apply even when the total remnant mass exceeds the maximum ma

Kostas D. Kokkotas, Bernd G. Schmidt

Perturbations of stars and black holes have been one of the main topics of relativistic astrophysics for the last few decades. They are of particular importance today, because of their relevance to gravitational wave astronomy. In this review we present the theory of quasi-normal modes of compact objects from both the mathematical and astrophysical points of

Ioannis Raptis

A quantum picture of the causal structure of Minkowski space M is presented. The mathematical model employed to this end is a non-classical version of the classical topos {H} of real quaternion algebras used elsewhere to organize the perceptions of spacetime events of a Boolean observer into M. Certain key properties of this new quantum topos are highlighted

Kazuhiro Tominaga, Motoyuki Saijo, Kei-ichi Maeda

Using a metric perturbation method, we study gravitational waves from a test particle scattered by a spherically symmetric relativistic star. We calculate the energy spectrum and the waveform of gravitational waves for axial modes. Since metric perturbations in axial modes do not couple to the matter fluid of the star, emitted waves for a normal neutron star

Luis Craco

The metallic phase of the two-orbital Anderson lattice is study in the limit of infinite spatial dimensions, where a second order perturbation treatment is used to solve the single-site problem. Using this approximation, in the Kondo regime, we find that the finite temperature properties of the conduction electrons exhibit the same behaviour as observed in t

H. F. Jones

We consider a complex periodic PT-symmetric potential of the Kronig-Penney type, in order to elucidate the peculiar properties found by Bender et al. for potentials of the form $V=i(\sin x)^{2N+1}$, and in particular the absence of anti-periodic solutions. In this model we show explicitly why these solutions disappear as soon as $V^*(x)\neq V(x)$, and spell

P. T. Coleridge, P. Zawadzki, A. Sachrajda, Y. Feng

The rich variety of phase transitions observed in the strained p-SiGe system are considered and compared. It is shown that the integer quantum Hall effect transitions, the Hall insulating transition and the re-entrant transition into an insulating phase near filling factor 3/2 are all very similar and good examples of quantum critical phase transitions. The

R. Balian, J. -P. Blaizot

The physics of stars, their workings and their evolution, is a goldmine of problems in statistical mechanics and thermodynamics. We discuss many examples that illustrate the possibility of deepening student's knowledge of statistical mechanics by an introductory study of stars. The matter constituting the various stellar objects provides examples of equa

Shunsaku Hirata, Kiyohide Nomura

We study the ground state properties of one-dimensional XXZ model with next-nearest neighbor coupling alpha and anisotropy Delta. We find the direct transition between the ferromagnetic phase and the spontaneously dimerized phase. This is surprising, because the ferromagnetic phase is classical, whereas the dimer phase is a purely quantum and nonmagnetic pha

S. K. Dallakyan, N. S. Ananikian, R. G. Ghulghazaryan

The mechanisms leading to thermodynamic chaos in the Baxter-Wu model is considered. We compare the Baxter-Wu model with triangular antiferromagnets and discuss the difficulties related to the modeling of thermodynamic chaos by disordered models. We also discuss how to overcome the problem of infinitely many order parameters. Then we consider the Baxter-Wu mo

Renuka Rai, Ramandeep S. Johal

We propose generalized bit cumulants for chaotic systems, within nonextensive thermodynamic approach. In this work, we apply the first and second generalized cumulants to one dimensional logistic and logistic-like family of maps.

Bosiljka Tadic

We propose and study numerically a stochastic cellular automaton model for the dynamics of granular materials with temporal disorder representing random variation of the diffusion probability $1-μ(t)$ around threshold value $1-μ_0$ during the course of an avalanche. Combined with the slope threshold dynamics, the temporal disorder yields a series of secondar

O. Bunk, G. Falkenberg, J. H. Zeysing, L. Lottermoser

A detailed structural model for the indium-induced Si(111)-(4x1) surface reconstruction has been determined by analyzing an extensive set of x-ray-diffraction data recorded with monochromatic ($\hbarω$ = 9.1 keV) synchrotron radiation. The reconstruction is quasi-one-dimensional. The main features in the structure are chains of silicon atoms alternating with

O. Bunk, J. H. Zeysing, G. Falkenberg, R. L. Johnson

Accurate atomic coordinates of the room-temperature (root3xroot3)R30degree and low-temperature (3x3) phases of 1/3 ML Sn on Ge(111) have been established by grazing-incidence x-ray diffraction with synchrotron radiation. The Sn atoms are located solely at T4-sites in the (root3xroot3)R30degree structure. In the low temperature phase one of the three Sn atoms

Min-Fong Yang, Ming-Che Chang

In this paper, the influence of an in-plane magnetic field B_\parallel on the finite-temperature phase transitions in nu=2 bilayer quantum Hall systems are examined. It is found that there can exist two types of finite-temperature phase transitions. The first is the Kosterlitz-Thouless (KT) transitions, which can have an unusual non-monotonic dependence on B

M. M. Aghasyan A. A. Kirakosyan

The electron states in a size-quantaized coated semiconductor wire in a uniform magnetic field applied parallel to the wire axis is considered. The wave functions are found and the equation for determination of energy eigenvalues depending both on magnetic field and parameters of the wire and the coating is obtained. The binding energy of a hydrogen-like imp

Eric W. Deutsch, Bruce Margon, Scott F. Anderson, Ronald A. Downes

Despite indications that classical cataclysmic variable (CV) stars are rare in globular clusters in general, and in the cluster NGC 6624 in particular, we have serendipitously discovered such a star ~6'' from the cluster center. A Hubble Space Telescope spectrum of the m~22 object shows strong, broad emission lines typical of numerous field CVs, and

Thierry Forveille, Jean Luc Beuzit, Xavier Delfosse, Damien Segransan

We present very accurate individual masses (1.2% relative accuracy) for the two components of Gl 570BC, an interferometric and double-lined spectroscopic binary system. They were obtained from new high accuracy radial velocity and angular separation measurements, analysed together with previously published measurements. From those data we determine a much im

Jeremy S. Heyl, Nir J. Shaviv

Extremely strong magnetic fields change the vacuum index of refraction. Although this polarization dependent effect is small for typical neutron stars, it is large enough to decouple the polarization states of photons traveling within the field. The photon states evolve adiabatically and follow the changing magnetic field direction. The combination of a rota

J. A. Munoz, E. E. Falco, C. S. Kochanek, B. A. McLeod

The lens candidate RXJ 0921+4529 consists of two z_s=1.66 quasar separated by 6."93 with an H band magnitude difference of Δm=1.39. The lens appears to be a z_l=0.31 X-ray cluster, including a m_H=18.5 late-type galaxy lying between the quasar images. We detect an extended source overlapping the faint quasar but not the bright quasar. If this extended so

Martin A. Guerrero

The discovery of collimated outflows associated to point-symmetric features in Planetary Nebulae has proliferated in recent years. The systematic variation of radial velocity that many of them show strongly suggests a uniform rotation or precession of the ejection direction. Although several physical processes have been invoked, the formation mechanism of pr

I. Neill Reid, J. Davy Kirkpatrick, J. E. Gizis, C. C. Dahn

We present spectroscopic, photometric and astrometric observations of four bright L dwarfs identified in the course of the 2MASS near-infrared survey. Our spectroscopic data extend to wavelengths shortward of 5000\AA in the L0 dwarf 2MASSJ0746+2000 and the L4 dwarf 2MASSJ0036+1840, allowing the identification of absorption bands due to MgH and CaOH. The atom

Joshua N. Winn, Jacqueline N. Hewitt, Paul L. Schechter

We present a status report on our search for multiple-image QSOs among southern radio sources. Our goal is to identify new lenses for use in studies of cosmology and galaxy structure. To date we have examined 3300 radio sources, identified one probable lens and one probable binary QSO along with about 50 candidates deserving further follow-up.

S. Corbel, C. Chapuis, T. M. Dame, P. Durouchoux

We report millimeter observations of the line of sight to the recently discovered Soft Gamma Repeater, SGR 1627-41, which has been tentatively associated with the supernova remnant SNR G337.0-0.1 Among the eight molecular clouds along the line of sight to SGR 1627-41, we show that SNR G337.0-0.1 is probably interacting with one of the most massive giant mole

E. Grün, M. Landgraf

Identification by the Ulysses spacecraft of interstellar grains inside the planetary system provides a new window for the study of diffuse interstellar matter. Dust particles observed by Ulysses and confirmed by Galileo are more massive ($\geq 10^{-13} {\rm g}$) than the 'classical' interstellar grains. Even bigger grains ($\approx 10^{-7} {\rm g}$)

G. Clementini, A. Bragaglia, E. Carretta, L. Di Fabrizio

The Large Magellanic Cloud (LMC) is widely considered a corner-stone of the astronomical distance scale, however a difference of 0.2-0.3 mag exists in its distance as predicted by the "short" and "long" distance scales. Distances to the LMC from Population II objects are founded on the RR Lyrae variables. We have undertaken an observational c

F. Kupka

The non-local hydrodynamic moment equations for compressible convection are compared to numerical simulations. Convective and radiative flux typically deviate less than 20% from the 3D simulations, while mean thermodynamic quantities are accurate to at least 2% for the cases we have investigated. The moment equations are solved in minutes rather than days on

A. J. Kemball, A. R. Patnaik, R. W. Porcas

We present preliminary polarisation VLBI maps of the gravitational lens system B0218+357, made at 3 different frequencies.

A. R. Patnaik, K. M. Menten, R. W. Porcas, A. J. Kemball

We present multi-frequency VLA polarisation observations of nine gravitational lenses. The aim of these observations was to determine Faraday rotation measures (RM) for the individual lensed images, and to measure their continuum spectra over a wide range of frequencies.

Tomofumi Umemoto, Hitomi Mikami, Satoshi Yamamoto, Naomi Hirano

We have measured the ortho-to-para ratio of ammonia in the blueshifted gas of the L1157 outflow by observing the six metastable inversion lines from (J, K) = (1, 1) to (6, 6). The highly excited (5, 5) and (6, 6) lines were first detected in the low-mass star forming regions. The rotational temperature derived from the ratio of four transition lines from (3,

Naoto Kobayashi, Alan T. Tokunaga

We report a discovery of young stellar objects associated with a molecular cloud at the edge of the optical disk of our Galaxy. This cloud is denoted as Cloud 2 in the list by Digel et al. and it is one of the most distant molecular clouds from the Galactic center known to date, with a probable distance of 15-19 kpc. We found seven red near-infrared sources

G. G. Pavlov, V. E. Zavlin

Since the opacity of a magnetized plasma depends on polarization of radiation, the radiation emergent from atmospheres of neutron stars with strong magnetic fields is expected to be strongly polarized. The degree of linear polarization, typically ~10-30%, depends on photon energy, effective temperature and magnetic field. The spectrum of polarization is more

Wolfgang Voges, Bernd Aschenbach, Thomas Boller, Heinrich Braeuninger

We present the ROSAT All-Sky Survey Bright Source Catalogue (RASS-BSC, revision 1RXS) derived from the all-sky survey performed during the first half year (1990/91) of the ROSAT mission. 18,811 sources are catalogued (i) down to a limiting ROSAT PSPC count-rate of 0.05 cts/s in the 0.1-2.4 keV energy band, (ii) with a detection likelihood of at least 15 and

J. Oitmaa, C. J. Hamer, Zheng Weihong

Series expansions at T=0 are used to study properties of the half-filled $t-J$ ladder doped with one or two holes, and at quarter filling. Dispersion curves are obtained for one-hole symmetric and antisymmetric (bonding and antibonding) excitations and for the two-hole bound state. The line in the phase diagram which separates bound and unbound states is det

W. G. Scott

It is argued that data from atmospheric and solar neutrino experiments point strongly to tri-maximal or bi-maximal lepton mixing. While (`optimised') bi-maximal mixing gives an excellent a posteriori fit to the data, tri-maximal mixing is an a priori hypothesis, which is not excluded, taking account of terrestrial matter effects.

A. Chamblin, G. W. Gibbons

We show that smooth domain wall spacetimes supported by a scalar field separating two anti-de-Sitter like regions admit a single graviton bound state. Our analysis yields a fully non-linear supergravity treatment of the Randall-Sundrum model. Our solutions describe a pp-wave propagating in the domain wall background spacetime. If the latter is BPS, our solut

Nick E. Mavromatos, Richard J. Szabo

We formulate an effective Schroedinger wave equation describing the quantum dynamics of a system of D0-branes by applying the Wilson renormalization group equation to the worldsheet partition function of a deformed sigma-model describing the system, which includes the quantum recoil due to the exchange of string states between the individual D-particles. We

H. C. Rosu

This is the English version of a friendly graduate course on Classical Mechanics, containing about 80% of the material I covered during the January-June 1999 semester at IFUG in the Mexican city of Leon. For the Spanish version, see physics/9906066

J. A. Belinchon

We consider several model with metric type FRW, with k=0 and with generic equation of state. We take into account too, the conservation principle for the energy-momentum tensor. We find trivially, a set of solutions through dimensional analysis. We emphasite that the solution for G depend on the equation of state and for the cosmological constant no.

M. V. Polyakov, A. Sibirtsev, K. Tsushima, W. Cassing

The possibility for an observation of a narrow penta-quark $Z^+$ baryon in $NN$ reactions is discussed. It is shown that the $pp{\to}nΣ^+K^+$ reaction at excess energies around 100 MeV above threshold provides optimal conditions for $Z^+$ baryon detection by an analysis of the $nK^+$ invariant mass spectrum, if the $Z^+$ mass is located around 1.5 GeV involv

Hiroyuki Ochiai

We prove that each counting function of the m-simple branched covers with a fixed genus of an elliptic curve is expressed as a polynomial of the Eisenstein series E_2, E_4 and E_6 . The special case m=2 is considered by Dijkgraaf.

Kenji Handa

Reversible measures of the Fleming-Viot process are shown to be characterized as quasi-invariant measures with a cocycle given in terms of the mutation operator. As applications, we give certain integral characterization of Poisson-Dirichlet distributions and a proof that the stationary measure of the step-wise mutation model of Ohta-Kimura with periodic bou

R. Vershynin

We extend the invertibility principle of J. Bourgain and L. Tzafriri to operators acting on arbitrary decompositions id = \sum x_j \otimes x_j, rather than on the coordinate one. The John's decomposition brings this result to the local theory of Banach spaces. As a consequence, we get a new lemma of Dvoretzky-Rogers type, where the contact points of the

Laurent Baulieu, Celine Laroche, Nikita Nekrasov

This paper is a shortened version of the previous work hep-th/9907099: We propose a topological quantum field theory as a twisted candidate to formulate covariant matrix strings. The model relies on the octonionic or complexified instanton equations defined on an eight dimensional manifold with reduced holonomy. To allow untwisting of the model without produ

Tsutomu T. Takeuchi

To determine the exact shape of the luminosity function (LF) of galaxies is one of the central problems in galactic astronomy and observational cosmology. The most popular method to estimate the LF is maximum likelihood, which is clearly understood with the concepts of the information theory. In the field of information theory and statistical inference, grea

Daniel G. Barci, E. S. Fraga, Rudnei O. Ramos

We study the detailed out of equilibrium time evolution of a homogeneous Bose-Einstein condensate.We consider a nonrelativistic quantum theory for a self-interacting complex scalar field, immersed in a thermal bath, as an effective microscopic model for the description of the Bose-Einstein condensate. This approach yields the following main results:(i) the i

Yoshiharu Eriguchi, Koji Uryu

In this paper, we have reviewed the present status of the theory of equilibrium configurations of compact binary star systems in Newtonian gravity. Evolutionary processes of compact binary star systems due to gravitational wave emission can be divided into three stages according to the time scales and configurations. The evolution is quasi-stationary until a

V. Bornyakov, A. Hoferichter, G. Schierholz, A. Thimm

The imaginary part of the effective action is investigated in the 4D chiral U(1) theory using the CFA.

Tetsuya Takaishi

We study efficiency of higher order integrator schemes for the hybrid Monte Carlo (HMC) algorithm. Numerical tests are performed for Quantum Chromo Dynamics (QCD) with two flavors of Wilson fermions. We compare 2nd, 4th and 6th order integrators at various quark masses. The performance depends on both volume and quark mass. On currently accessible large latt

Wuliang Huang, Xiaodong Huang

We extend mass scale sequence to a mass tree. From mass tree, the evolution of the universe is described by three stages: chaos, inflation and expansion. The first two stages have c mutations and the inflation appears as a step by step fission process of black holes. The dark matter particles with low mass (neutrino and delta particle) are described in a dua

Dave Bacon, Julia Kempe, Daniel A. Lidar, K. B. Whaley

A general scheme to perform universal quantum computation within decoherence-free subspaces (DFSs) of a system's Hilbert space is presented. This scheme leads to the first fault-tolerant realization of universal quantum computation on DFSs with the properties that (i) only one- and two-qubit interactions are required, and (ii) the system remains within t

Marco A. C. Kneipp

Soliton time-delays and the semiclassical limit for soliton S-matrices are calculated for non-simply laced Affine Toda Field Theories. The phase shift is written as a sum over bilinears on the soliton conserved charges. The results apply to any two solitons of any Affine Toda Field Theory. As a by-product, a general expression for the number of bound states

D. A. Gryaznykh, Y. Z. Kandiev, V. A. Lykov

Electron-positron pairs' generation occuring in the interaction of $10^{18}$-$10^{20}$~W/cm$^2$ laser radiation with high-Z targets are examined. Computational results are presented for the pair production and the positron yield from the target with allowance for the contribution of pair production processes due to electrons and bremsstrahlung photons. M

Takumi Muto, Toshitaka Tatsumi, Naoki Iwamoto

The kinetics of negatively charged kaon condensation in the early stages of a newly born neutron star is considered. The thermal kaon process, in which kaons are thermally produced by nucleon-nucleon collisions, is found to be dominant throughout the equilibration process. Temporal changes of the order parameter of the condensate and the number densities of

Tomasz Brzezinski

Two cochain complexes are constructed for an algebra A and a coalgebra C entwined with each other via the map $ψ:C\otimes A\to A\otimes C$. One complex is associated to an A-bimodule, the other to a C-bicomodule. In the former case the resulting complex can be considered as a $ψ$-twisted Hochschild complex of A, while for the latter one obtains a $ψ$-twist o

G. I. Barenblatt, A. J. Chorin, V. M. Prostokishin

In recent papers Benzi et al. presented experimental data and an analysis to the effect that the well-known "2/3" Kolmogorov-Obukhov exponent in the inertial range of local structure in turbulence should be corrected by a small but definitely non-zero amount. We reexamine the very same data and show that this conclusion is unjustified. The data are i

Dirk Kreimer

The recently discovered formalism underlying renormalization theory, the Hopf algebra of rooted trees, allows to generalize Chen's lemma. In its generalized form it describes the change of a scale in Green functions, and hence relates to the operator product expansion. Hand in hand with this generalization goes the generalization of the ordinary factoria

Jai Sam Kim, C. W. Kim

We have numerically computed survival probabilities of solar neutrinos interacting with matter via MSW mechanism in the full three generation formalism with $Δm^2_{23}=2.2\times 10^{-3}$ eV$^2$. For $θ_{13} \lesssim 30^{\circ}$, we confirm the two regions found in the two generation case, (1) with the most likelyhood, small $\sin^2(2θ_{12}) \sim 0.006$, (2)

M. Al-Saqer, V. V. Dobrovitski, B. N. Harmon, M. I. Katsnelson

Spin tunneling in molecular magnets has attracted much attention, however theoretical considerations of this phenomenon up to now have not taken into account the many-spin nature of molecular magnets. We present, to our knowledge, the first successful attempt of a realistic calculation of tunneling splittings for Mn$_{12}$ molecules, thus achieving a quantit

David M. Sedrakian, Ashot Zh. Khachatrian

The linear system of differential equations for determination of transmission and reflection amplytudes of scattered electron in the field of one dimensional arbitrary potential is obtained. It is shown that in general the scattering problem can be reduced to the Caushy problem for the stationary Shrodinger equation. An explicit functional for a dependance o

S. G. Rubin

A system of strongly interacting fermions in a solid state is discussed. A structure of singlet and triplet coupled 2-particle states and their excitation spectra are investigated. It is shown that an account of intersite fermion interaction leads to new boson modes. A problem of interaction of pairs with external fields are discussed. The same analysis can

Konstantin Kladko, Igor Mitkov, A. R. Bishop

We study the onset of the propagation failure of wave fronts in systems of coupled cells. We introduce a new method to analyze the scaling of the critical external field at which fronts cease to propagate, as a function of intercellular coupling. We find the universal scaling of the field throughout the range of couplings, and show that the field becomes exp

Ron Lifshitz

The theory of magnetic symmetry in quasicrystals is used to characterize the nature of magnetic peaks, expected in elastic neutron diffraction experiments. It is established that there is no symmetry-based argument which forbids the existence of quasiperiodic long-range magnetic order. Suggestions are offered as to where one should look for the simplest kind

J. Siebert, S. Komossa, W. Brinkmann

IRAS13349+2438 was the first quasar suggested to host a warm absorber with internal dust. We obtained new HRI data for this object and derive constraints on the X-ray emitting region of IRAS13349+2438 by investigating its X-ray extent and lightcurve. Rapid X-ray variability is detected with a factor of two change in count rate within one day and 20% variabil

Ole Moeller, Priyamvada Natarajan

A large fraction of known galaxy-lens systems require a component of external shear to explain the observed image geometries. In most cases, this shear can be attributed to a nearby group of galaxies. We discuss how the dark-matter mass distribution of groups of galaxies can influence the external shear for strongly lensed sources and Calculate the expected

Hartmut Schmieden, Lothar Tiator

For pseudoscalar meson electroproduction off the nucleon in parallel kinematics a relation between three polarization observables is derived. It is shown that, without Rosenbluth separation, a measurement of the longitudinal strength can be achieved through three different ways. They are discussed with preliminary MAMI data for the p(\vec e, e'\vec p)π^0

Greg Kuperberg

Recently Tracy and Widom conjectured [math.CO/9904042] and Johansson proved [math.CO/9906120] that the expected shape λof the semi-standard tableau produced by a random word in k letters is asymptotically the spectrum of a random traceless k by k GUE matrix. In this article we give two arguments for this fact. In the first argument, we realize the random mat

Andrea Romanino

We discuss the prospects of observing leptonic CP-violation at a neutrino factory in the context of the standard three neutrino scenario. If the large mixing angle MSW effect turned out to account for the solar neutrino deficit, we show that observing an asymmetry between the $\reu$ and $\reub$ oscillation probabilities would represent an exciting experiment

Yu. G. Pashkevich, V. A. Blinkin, V. P. Gnezdilov, V. V. Tsapenko

We report Raman light-scattering and optical conductivity measurements on a single crystal of La(1.775)Sr(0.225)NiO(4) which exhibits incommensurate charge-stripe order. The extra phonon peaks induced by stripe order can be understood in terms of the energies of phonons that occur at the charge-order wave vector, Q_c. A strong Fano antiresonance for a Ni-O b

Sergey S. Stepanov

We consider a hypothetical possibility of the variability of light velocity with time and position in space which is derived from two natural postulates. For the consistent consideration of such variability we generalize translational transformations of the Theory of Relativity. The formulae of transformations between two rest observers within one inertial s

Alain Connes, Dirk Kreimer

We show that renormalization in quantum field theory is a special instance of a general mathematical procedure of multiplicative extraction of finite values based on the Riemann-Hilbert problem. Given a loop $γ(z), | z |=1$ of elements of a complex Lie group G the general procedure is given by evaluation of $ γ_{+}(z)$ at z=0 after performing the Birkhoff de

Thomas Papenbrock

We study a generalized three-dimensional stadium billiard and present strong numerical evidence that this system is completely chaotic. In this convex billiard chaos is generated by the defocusing mechanism. The construction of this billiard uses cylindrical components as the focusing elements and thereby differs from the recent approach pioneered by Bunimov

K. A. Ter-Martirosyan, D. A. Ryzhikh

A general approach for construction of quark and lepton mass matrices is formulated. The hierarchy of quarks and charged leptons ("electrons") is large, it leads using the experimental values of mixing angles to the hierarchical mass matrix slightly deviating from one's suggested earlier by Stech and including naturally the CP-phase. The same met

N. Iwasa, F. Boue, G. Surowka, K. Suemmerer

We have measured the Coulomb dissociation of 8B into 7Be and proton at 254 MeV/nucleon using a large-acceptance focusing spectrometer. The astrophysical S17 factor for the 7Be(p,gamma)8B reaction at E{c.m.} = 0.25-2.78 MeV is deduced yielding S17(0)=20.6 \pm 1.2 (exp.) \pm 1.0 (theo.) eV-b. This result agrees with the presently adopted zero-energy S17 factor

A. Sacuto, J. Cayssol, D. Colson, P. Monod

In order to obtain high quality, reliable electronic Raman spectra of a high-Tc superconductor compound, we have studied strongly under-doped HgBa2Ca2Cu3O8+d. This choice was made such as to i)minimize oxygen disorder in the Hg-plane generated by oxygen doping ii) avoid the need of phonon background subtraction from the raw data iii)eliminate traces of paras

Pavel Bóna

We are dealing in this work with such formal and conceptual extensions of nonrelativistic quantum mechanics (QM) which contain QM with its standard formalism and interpretation as a subtheory. QM is here primarily equivalently reformulated in the form of a Poisson system on the infinite-dimensional phase space consisting of all density matrices. It is shown

Stephen Godfrey, Pat Kalyniak, Basim Kamal, Arnd Leike

We study the sensitivity of the process e^+ e^- \to ν\barνγto extra gauge bosons, particularly W' bosons. Depending on the model, evidence for extra W bosons in this process can be detected for W' masses up to several TeV.

Elena Pierpaoli, Juan Garcia-Bellido, Stefano Borgani

In this paper we study the isocurvature mode contribution to the cosmic microwave background anisotropies and the large scale structure power spectrum, for a two-field model of inflation proposed by Linde and Mukhanov. We provide constraints on the parameters of the model by comparing its predictions with observations of the microwave background anisotropies

R. Casalbuoni, R. Gatto

We study the color-flavor locked phase of QCD with three massless quarks at high chemical potential and small non zero temperatures. We make use of the recently introduced effective action to describe such a phase. We obtain the exact order T^2 behaviour of the condensates and of the pressure by formally comparing the derivative from the QCD functional with

A. Dedes, S. Moretti

If the soft Supersymmetry (SUSY) breaking masses and couplings are complex, then the associated CP-violating phases can in principle modify the known phenomenological pattern of the Minimal Supersymmetric Standard Model (MSSM). We investigate here their effects on Higgs boson production in the gluon-gluon fusion mode at the Tevatron and the Large Hadron Coll

Hongchen Fu, Yinqi Feng, A. I. Solomon

Using the eigenvalue definition of binomial states we construct new intermediate number-coherent states which reduce to number and coherent states in two different limits. We reveal the connection of these intermediate states with photon-added coherent states and investigate their non-classical properties and quasi-probability distributions in detail. It is

B. Jancovici, P. Kalinay, L. Samaj

In a two-dimensional two-component plasma, the second moment of the number density correlation function has the simple value $\{12 π[1-(Γ/4)]^2\}^{-1}$, where $Γ$ is the dimensionless coupling constant. This result is derived directly by using diagrammatic methods.

A. Schiller, A. Bjerve, M. Guttormsen, M. Hjorth-Jensen

The level density at low spin in the 161,162-Dy and 171,172-Yb nuclei has been extracted from primary gamma rays. The nuclear heat capacity is deduced within the framework of the canonical ensemble. The heat capacity exhibits an S-formed shape as a function of temperature, which is interpreted as a fingerprint of the phase transition from a strongly correlat

Kiko Fukuura, Takahiro Miura, Eiichi Takasugi, Masaki Yoshimura

We propose a democratic-type neutrino mass matrix based on $Z_3$ symmetry. This mass matrix predicts the CP violation phase, $δ=π/2$, and the mixing angle between the mass eigenstates $ν_2$ and $ν_3$, $\sin^2 θ_{23}= \cos^2 θ_{23}=1/2$ which is essential for the large atmospheric neutrino mixing, between $ν_μ$ and $ν_τ$. In this model, the large CP violation

Satish D. Joglekar, A. Misra

The propagators in axial-type, light-cone and planar gauges contain 1/(η\cdot k)^p-type singularities. These singularities have generally been treated by inventing prescriptions for them. In this work, we propose an alternative procedure for treating these singularities in the path integral formalism using the known way of treating the singularities in Loren

Wei Bao, R. J. McQueeney, R. Heffner, J. L. Sarrao

When sufficient numbers of holes are introduced into the two-dimensional CuO2 square lattice, dynamic magnetic correlations become incommensurate with underlying lattice in all previously investigated La_{2-x}A_xCu_{1-z}B_zO_{4+y} (A=Sr or Nd, B=Zn) including high T_C superconductors and insulators, and in bilayered superconducting YBa_2Cu_3O_{6.6} and Bi_2S

P. G. Estevez, G. A. Hernaez

We use the singular manifold method to obtain the Lax pair, Darboux transformations and soliton solutions for a (2+1) dimensional integrable equation.

A. Vidiella-Barranco

It is presented a generalization of the von Neumann mutual information in the context of Tsallis' nonextensive statistics. As an example, entanglement between two (two-level) quantum subsystems is discussed. Important changes occur in the generalized mutual information, which measures the degree of entanglement, depending on the entropic index q.

A. P. Balachandran, S. M. Roy

We establish an exact differential equation for the operator describing time-dependent measurements continuous in time and obtain a series solution. Suppose the projection operator $E(t) = U(t) E U^\dagger(t)$ is measured continuously from t = 0 to T, where E is a projector leaving the initial state unchanged and U(t) a unitary operator obeying U(0) = 1 and

Jeffrey D. Scargle

Publication bias arises whenever the probability that a study is published depends on the statistical significance of its results. This bias, often called the file-drawer effect since the unpublished results are imagined to be tucked away in researchers' file cabinets, is potentially a severe impediment to combining the statistical results of studies col

Xiao-Gang Wang, Edwin L. Sibert, Jan M. L. Martin

Accurate quartic anharmonic force fields for CF$_4$ and SiF$_4$ have been calculated using the CCSD(T) method and basis sets of $spdf$ quality. Based on the {\it ab initio} force field with a minor empirical adjustment, the vibrational energy levels of these two molecules and their isotopomers are calculated by means of high order Canonical Van Vleck Perturb

M. V. Ivanov, P. Schmelcher

The ground and a few excited states of the carbon atom in external uniform magnetic fields are calculated by means of our 2D mesh Hartree-Fock method for field strengths ranging from zero up to 2.35 10^9 T. With increasing field strength the ground state undergoes six transitions involving seven different electronic configurations which belong to three group

Vladimir S. Melezhik, Peter Schmelcher

It is shown that one can stimulate, by using the present-day laboratory magnetic fields, transitions between the $lm$ sub-levels of fast $μHe^+$ ions formating in muon catalyzed fusion. Strong fields also cause the self-ionization from highly excited states of such muonic ions. Both effects are the consequence of the interaction of the bound muon with the os

Hiroki Nakamura, Ryoichi Seki

Two- and three-pion correlations are investigated in cases when disoriented chiral condensate (DCC) occurs. A chaoticity and weight factor are used as measures of two- and three-pion correlations, and the various models for DCC are investigated. Some models are found to yield the chaoticity and weight factor in a reasonable agreement with recent experimental

Hiroki Nakamura, Ryoichi Seki

Two- and three-pion correlation functions are investigated for a source that is not fully chaotic. Various models are examined to describe the source. The chaoticity and weight factor are evaluated in each model as measures of the strength of correlations and compared to experimental results. A new measure of three-pion correlation is also suggested.

Hiroki Nakamura, Ryoichi Seki

Three-pion interferometry is investigated for new information on the space-time structure of the pion source created in ultra-relativistic heavy-ion collisions. The two- and three-pion correlations are numerically computed for incoherent source functions based on the Bjorken hydrodynamical model, over a wide range of the kinematic variables. New information

Haruki Kurasawa, Toshio Suzuki

Effects of the Dirac sea on the excitation energy of the giant monopole states are investigated in an analytic way within the $σ-ω$ model. The excitation energy is determined by the relativistic Landau-Migdal parameters, $F_0$ and $F_1$. Their analytic expressions are derived in the relativistic random phase approximation(RRPA) without the Dirac sea, with th

Anthony W. Thomas, Derek B. Leinweber, Kazuo Tsushima, Stewart V. Wright

Consideration of the analytic properties of pion-induced baryon self energies leads to new functional forms for the extrapolation of light baryon masses. These functional forms reproduce the leading non-analytic behavior of chiral perturbation theory, the correct non-analytic behavior at the $N \pi$ threshold and the appropriate heavy-quark limit. They invol

Sanjay Reddy, George Bertsch, Madappa Prakash

A first order phase transition at high baryon density implies that a mixed phase can occupy a significant region of the interior of a neutron star. In this article we investigate the effect of a droplet phase on neutrino transport inside the core. Two specific scenarios of the phase transition are examined, one having a kaon condensate and the other having q