April 1998 arXiv papers — page 14

Roberto Casadio

A family of effective actions in Hamiltonian form is derived for a self-gravitating sphere of isotropic homogeneous dust. Starting from the Einstein-Hilbert action for barotropic perfect fluids and making use of the symmetry and equation of state of the matter distribution we obtain reduced actions for two canonical variables, namely the radius of the sphere

Chandrashekar Devchand, Jean Nuyts

Superalgebras including generators having spins up to two and realisable as tangent vector fields on Lorentz covariant generalised superspaces are considered. The latter have a representation content reminiscent of configuration spaces of (super)gravity theories. The most general canonical supercommutation relations for the corresponding phase space coordina

W. C. Haxton

The 51Cr neutrino source experiments play a unique role in testing overall operations of the GALLEX and SAGE solar neutrino experiments. Recently Hata and Haxton argued that the excited-state contribution to the 71Ga cross section for 51Cr neutrino absorption might not be known reliably, despite forward-angle (p,n) measurements. A large-basis shell model cal

L. A. Manzoni, B. M. Pimentel, J. L. Tomazelli

We evaluate the one-loop fermion self-energy for the gauged Thirring model in (2+1) dimensions, with one massive fermion flavor, in the framework of the causal perturbation theory. In contrast to QED$_3$, the corresponding two-point function turns out to be infrared finite on the mass shell. Then, by means of a Ward identity, we derive the on-shell vertex co

Max Tegmark, P. J. E. Peebles

We study the evolution of the bias factor b and the mass-galaxy correlation coefficient r in a simple analytic model for galaxy formation and the gravitational growth of clustering. The model shows that b and r can be strongly time-dependent, but tend to approach unity even if galaxy formation never ends as the gravitational growth of clustering debiases the

Yakir Aharonov, Benni Reznik, Ady Stern

Unstable systems such as media with inverted atomic population have been shown to allow the propagation of analytic wavepackets with group velocity faster than that of light, without violating causality. We illuminate the important role played by unstable modes in this propagation, and show that the quantum fluctuations of these modes, and their unitary time

Valeri V. Dvoeglazov

In the sixties Ogievetskii and Polubarinov proposed the concept of a notoph, whose helicity properties are complementary to those of a photon. We analyze the theory of antisymmetric tensor fields in the view of the normalization problem. The obtained result is that it is possible to describe both photon and notoph degrees of freedom on the basis of the modif

Mingming Wu, Moteza Gharib

Experiments are conducted to study the path and shape of single air bubbles (diameter range 0.10- 0.20cm) rising freely in clean water. The experimental results demonstrate that the bubble shape has a bistable state, i. e. the bubble chooses to be in spherical or ellipsoidal shape depending on its generation mechanism. The path of a spherical/ellipsoidal bub

P. Navratil, B. R. Barrett

Results of large-basis shell-model calculations for nuclei with A=7-11 are presented. The effective interactions used in the study were derived microscopically from the Reid93 potential and take into account the Coulomb potential as well as the charge dependence of T=1 partial waves. For A=7, a $6\hbarΩ$ model space was used, while for the rest of the studie

G. Q. Li, G. E. Brown

We study $K^-/K^+$ ratios as a function of centrality (participant nucleon number), transverse mass ($m_t$), and rapidity, in heavy-ion collisions at beam energies between 1A and 2A GeV. We use the relativistic transport model that includes expicitly the strangeness degrees of freedom and consider two scenarios for kaon properties in dense matter, one with a

Hong-Ming Yin

In this paper we study the following nonlinear Maxwell's equations \\ $\varepsilon \E_{t}+σ(x,|\E|)\E= \g \vh +\F,\, \vh_{t}+\g \E=0$, where $σ(x,s)$ is a monotone graph of $s$. It is shown that the system has a unique weak solution. Moreover, the limit of the solution as $\varepsilon\rightarrow 0$ converges to the solution of quasi-stationary Maxwell&#3

Anders S. Buch, William Fulton

In this paper a formula is proved for the general degeneracy locus associated to an oriented quiver of type A_n. Given a finite sequence of vector bundles with maps between them, these loci are described by putting rank conditions on arbitrary composites of the maps. Our answer is a polynomial in Chern classes of the bundles involved, depending on the given

Krystyna Kuperberg, Włodzimierz Kuperberg, Jiří Matoušek, Pavel Valtr

For any delta > 1 we construct a periodic and locally finite packing of the plane with ellipses whose delta-enlargement covers the whole plane. This answers a question of Imre Bárány. On the other hand, we show that if C is a packing in the plane with circular discs of radius at most 1, then its 1.00001-enlargement covers no square with side length 4.

Mark Shimozono

Answering a question of Kuniba, Misra, Okado, Takagi, and Uchiyama, it is shown that certain Demazure characters of affine type A, coincide with the graded characters of coordinate rings of closures of conjugacy classes of nilpotent matrices. This entails a translation of the affine type A crystal theory into the language of tableaux following Nakayashiki an

Mark Shimozono

The generalized Kostka polynomials are the Poincare polynomials of isotypic components of certain graded GL(n)-modules. The former satisfy a monotonicity property arising from natural surjections of the corresponding modules. This monotonicity property is realized combinatorially by a directed system of order- and statistic-preserving embeddings between the

Mark Shimozono

A graded poset structure is defined for the sets of Littlewood-Richardson (LR) tableaux that count the multiplicity of an irreducible GL(n)-module in the tensor product of irreducibles indexed by a sequence of rectangular partitions. This poset generalizes the cyclage poset on column-strict tableaux defined by Lascoux and Schutzenberger, and its grading func

Mark Shimozono, Jerzy Weyman

We study the Poincare polynomials of isotypic components of a natural family of graded GL(n)-modules supported in the closure of a nilpotent conjugacy class. These polynomials generalize the Kostka-Foulkes and are q-analogues of Littlewood-Richardson coefficients corresponding to arbitrary tensor products of irreducibles. Many properties and formulas for the

Gia Giorgadze

We discuss some topological aspects of the Riemann-Hilbert transmission problem and Riemann-Hilbert monodromy problem on Riemann surfaces. In particular, we describe the construction of a holomorphic vector bundle starting from the given representation of the fundamental group and investigate the local behaviour of connexions on this bundle. We give formulae

Thomas Peternell, Michael Schneider, Andrew J. Sommese

In this article we study how the birational geometry of a normal projective variety $X$ is influenced by a normal subvariety $A \subset X.$ One of the most basic examples in this context is provided by the following situation. Let $f:X\to Y$ be a surjective holomorphic map with connected fibers between compact connected complex manifolds. It is well known th

Enrique Arrondo, Laura Costa

We study the vector bundles without intermediate cohomology on Fano threefolds of index two, degree d=3,4,5 and Betti number one. We obtain a complete characterization in the case of rank-two vector bundles. For arbitrary rank, we give all possible Chern classes of such vector bundles, under some general condition.

Joan S. Birman, K. H. Ko, J. S. Lee

A new presentation of the $n$-string braid group $B_n$ is studied. Using it, a new solution to the word problem in $B_n$ is obtained which retains most of the desirable features of the Garside-Thurston solution, and at the same time makes possible certain computational improvements. We also give a related solution to the conjugacy problem, but the improvemen

F. Cordaro, P. Fre', L. Gualtieri, P. Termonia

In this paper we reconsider, for N=8 supergravity, the problem of gauging the most general electric subgroup. We show that admissible theories are fully characterized by a single algebraic equation to be satisfied by the embedding of the gauge group G within the electric subalgebra SL(8,\IR) of E_{7(7)}. The complete set of solutions to this equation contain

Noriaki Ikeda

The new method based on the operator formalism proposed by Abe and Nakanishi is applied to the quantum nonlinear abelian gauge theory in two dimension. The soluble models in this method are extended to wider class of quantum field theories. We obtain the exact solution in the canonical-quantization operator formalism in the Heisenberg picture. So this analys

P. S. Howe, O. Raetzel, E. Sezgin

Actions for branes, with or without worldsurface gauge fields, are discussed in a unified framework. A simple algorithm is given for constructing the component Green-Schwarz actions. Superspace actions are also discussed. Three examples are given to illustrate the general procedure: the membrane in D=11 and the D2-brane, which both have on-shell worldsurface

Takeshi Oota

Two point correlation functions of the off-critical primary fields ϕ_{1, 1+s} are considered in the perturbed minimal models M_{2, 2N+3} + ϕ_{1,3}. They are given as infinite series of form factor contributions. The form factors of ϕ_{1, 1+s} are conjectured from the known results for those of ϕ_{1,2} and ϕ_{1,3}. The conjectured form factors are rewritten i

Toshinao Akuzawa, Miki Wadati

It was conjectured by Jackson et.al. that the finite volume effective partition function of QCD with the topological charge $M-N$ coincides with the Itzyskon-Zuber type integral for $M\times N$ rectangular matrices. In the present article we give a proof of this conjecture, in which the original Itzykson-Zuber integral is utilized.

H. W. Griesshammer

A Lagrangean and a set of Feynman rules are presented for Non-Relativistic QCD with manifest power counting in the heavy quark velocity $v$. A régime is identified in which energies and momenta are of order $Mv$. It is neither identical to the ultrasoft régime corresponding to radiative processes with energies and momenta of order $Mv^2$, nor to the potentia

G. Aldazabal

We indicate how consistent heterotic orbifold compactifications, including non perturbative information, can be constructed. We first analyse the situation in six dimensions, N=1, where strong coupling effects, implying the presence of five branes, are better known. We show that anomaly free models can be obtained even when usual modular invariance constrain

George Chiladze, Adam F. Falk, Alexey A. Petrov

We study the production of charmonium hybrids in B decays. We use the operator product expansion and nonrelativistic QCD to organize the various contributions to this process. We express the decay rate in terms of a few matrix elements which eventually will be fixed by experimental measurements or calculated on the lattice. While the Fock state expansion is

R. A. Alanakyan

In the framework of models with R-parity violation, scalar neutrinos and scalar leptons production in the processes $l_i^+l_j^-\to\tilde ν_{k,L} Z^0$ and $l^+_il^-_j\to \tilde{l}^{\mp}_{k,L}W^{\pm}$ is considered.We also consider within the Minimal Supersymmetric Standard Model Higgs bosons production in the processes $μ^+μ^-\toH_i^0Z^0$, $μ^+μ^-\to H^{\pm}W

Wang Xin, Li Jiarong

Within the real-time formalism (RTF) of thermal field theory,we apply the hard thermal loop (HTL) resummation technique to calculating effective two-loop thermodynamic potential in quark-gluon plasma (QGP) and its renormalization. The result with collective effects is obtained, which is valid for an arbitrary number of quark flavors with masses.

Robert Kinyua, Eiichi Takasugi

The lepton number violating process, $e^- e^- \to W^- W^-$ has been widely discussed in the Majorana neutrino exchange mechanism. Here, we discuss this process in a composite neutrino model where excited Majorana neutrinos are exchanged. We found several qualitatively different features from the neutrino exchange case: (1) The longitudinally polarized $W$&#3

Winfried Zimdahl, Diego Pavon

Using the existence of a covariant conserved quantity on large perturbation scales in a spatially flat perfect fluid or scalar field universe, we present a general formula for gauge-invariantly defined comoving energy density perturbations which encodes the entire linear perturbation dynamics in a closed time integral. On this basis we discuss perturbation m

Y. Itoh, M. Hotta, T. Futamase, M. Morikawa

We investigate the possibility of statistical explanation of the black hole entropy by counting quasi-bounded modes of thermal fluctuation in two dimensional black hole spacetime. The black hole concerned is quantum in the sense that it is in thermal equilibrium with its Hawking radiation. It is shown that the fluctuation around such a black hole obeys a wav

Carlo Rovelli

I review the present theoretical attempts to understand the quantum properties of spacetime. In particular, I illustrate the main achievements and the main difficulties in: string theory, loop quantum gravity, discrete quantum gravity (Regge calculus, dynamical triangulations and simplicial models), Euclidean quantum gravity, perturbative quantum gravity, qu

E. H. Rezayi, S. L. Sondhi

Quantum Hall skyrmions are quantized solitons of a ferromagnetic O(3) sigma-model. The reference, classical, solutions depend upon the interaction between the electrons and exhibit completely different asymptotic profiles for the physical Coulomb interaction than for the model hard core interaction frequently used to generate variational wavefunctions. In th

E. V. Goldstein, O. Zobay, P. Meystre

In analogy to Glauber's analysis of optical coherence, we adopt an operational approach to introduce different classes of atomic coherence associated with different types of measurements. For the sake of concreteness we consider specifically fluorescence, nonresonant imaging, and ionization. We introduce definitions of coherence appropriate to them, whic

J. T. Titantah, M. N. Hounkonnou

The long time effect of a radio frequency (rf) a.c. field superimposed on a d.c. field on the electrical susceptibility and the Kerr optical functions of polarisable fluids in inert solvent is analysed. The results obtained for the classical Brownian limit, valid for dense solvent media, well reproduce classical results published in the literature with excel

H. Diamant, D. Andelman

We present a model for the joint self-assembly of amphiphilic polymers and small amphiphilic molecules (surfactants) in a dilute aqueous solution. The polymer is assumed to consist of a hydrophilic backbone and a large number of hydrophobic side groups. Preference of the surfactant to bind to hydrophobic microdomains along the polymer induces an effective at

S. Franz, G. Parisi

In two recent interesting letters evidence was presented for the existence of a growing dynamic correlation length when we approach the glass transition from the liquid phase (a similar divergence is present also in the off-equilibrium dynamics below $T_c$). Here we would like to point out that this phenomenon can be easily predicted using the replica approa

H. W. Diehl, M. Shpot

The massive field-theory approach for studying critical behavior in fixed space dimensions $d<4$ is extended to systems with surfaces.This enables one to study surface critical behavior directly in dimensions $d<4$ without having to resort to the $ε$ expansion. The approach is elaborated for the representative case of the semi-infinite $|\bboxϕ|^4$ $n$-vecto

O. V. Dolgov, O. V. Danylenko, M. L. Kulic, V. Oudovenko

The sharp forward electron-phonon $(FEP)$ and impurity $(FIS)$ scattering change the normal and superconducting properties significantly. The pseudo-gap like features are present in the density of states for $ω<Ω$, where $Ω$ is the phonon frequency. The superconducting critical temperature $T_c$, due to the $FEP$ pairing, is linear with respect to the electr

Massimo Conti, Baruch Meerson, Pavel V. Sasorov

Our numerical simulations with the Cahn-Hilliard equation show that coarsening of fractal clusters (FCs) is not a scale-invariant process. On the other hand, a typical coarsening length scale and interfacial area of the FC exhibit power laws in time, while the mass fractal dimension remains invariant. The initial value of the lower cutoff is a relevant lengt

Raymond F. Bishop, Damian J. J. Farnell, John B. Parkinson

The coupled cluster method (CCM) is a well-known method of quantum many-body theory, and here we present an application of the CCM to the spin-half J_1--J_2 quantum spin model with nearest- and next-nearest-neighbour interactions on the linear chain and the square lattice. We present new results for ground-state expectation values of such quantities as the e

G. E. Volovik

We discuss the effective metric produced in superfluid 3He-A by such topological objects as radial disgyration and monopole. In relativistic theories these metrics are similar to that of the local string and global monopole correspondingly. But in 3He-A they have the negative angle deficit, which corresponds to the negative mass of the topological objects. T

Erik Koch, Olle Gunnarsson, Richard M. Martin

For conventional superconductors the electron-electron interaction is strongly reduced by retardation effects, making the formation of Cooper pairs possible. In the alkali-doped Fullerides, however, there are no strong retardation effects. But dielectric screening can reduce the electron-electron interaction sufficiently, if we assume that the random-phase a

Hideki Tanaka, Kazuhiro Kuboki, Manfred Sigrist

We study the effect of nonmagnetic impurities in the superconducting state of the t-J model. The Bogoliubov de Gennes equation is derived using a slave-boson mean-field approximation, and we solve it numerically at T=0. The d_{x^2-y^2}-wave order parameter is suppressed near an impurity and its spatial variation induces the extended s-wave component. We also

V. S. Podolsky

We study 2D-polaritons in an atomically thin dipole-active layer (2D-crystal) placed inside a parallel-plate wavegude, and investigate the possibility to obtain the localized wavegude modes associated with atomic defects. Considering the wavegude width, $l,$ as an adjustable parameter, we show that in the waveguide with $l\sim 10^{4} a,$ where $a$ is the lat

G. Gallavotti, G. Gentile, V. Mastropietro

Results in the mentioned paper do not seem valid.

Gabriel Carlo, Eduardo Vergini, Alejandro Fendrik

In order to verify Percival&#39;s conjecture [J. Phys. B 6,L229 (1973)] we study a planar billiard in its classical and quantum versions. We provide an evaluation of the nearest-neighbor level-spacing distribution for the Cassini oval billiard, taking into account relations with classical results. The statistical behavior of integrable and ergodic systems ha

Arul Lakshminarayan

Relaxation in the time correlation between operators is studied. Quantized chaotic systems are shown to have distinct relaxation fluctuations that are universal and can be usefully modelled by Random Matrix Theory. Various quantized maps are used to demonsrate these results.

J. B. Hutchings

The QSO 1345+584 has been spatially resolved by direct images and in spectral images, and has extended flux asymmetrically to the W, where its inner radio structure is seen. The brightest knots in the resolved flux correspond closely with knots in the curved radio jet, and the brightest knot has velocity of approach of some 3000 km/s with respect to the nucl

O. E. B. Messer, A. Mezzacappa, S. W. Bruenn, M. W. Guidry

Core-collapse supernovae are, despite their spectacular visual display, neutrino events. Virtually all of the 10^53 ergs of gravitational binding energy released in the formation of the nascent neutron star is carried away in the form of neutrinos and antineutrinos of all three flavors, and these neutrinos are primarily responsible for powering the explosion

Matthew Colless

The 2dF Galaxy Redshift Survey is a major new initiative to map a representative volume of the universe. The survey makes use of the 2dF multi-fibre spectrograph at the Anglo-Australian Telescope to measure redshifts for over 250,000 galaxies brighter than B=19.5 and a further 10,000 galaxies brighter than R=21. The main goals of the survey are to characteri

M. Boettcher, C. D. Dermer

The synchrotron reflection scenario recently proposed to explain $γ$-ray flares observed from blazar jets is studied. Our analysis takes into account the angular distribution of the beamed radiation, the finite extent of the scattering region, and light travel-time effects. We compare energy densities and powers for synchrotron, SSC, reflected synchrotron (R

A. Baudry, F. Herpin, R. Lucas

We have observed with the IRAM interferometer at two different epochs and simultaneously the two transitions v=0, J=2-1 and v=1, J=2-1 of 29SiO and 28SiO in Orion IRc2. We have made the first maps of 29SiO v=0, J=2-1 emission from Orion. These maps and properties of the 29SiO spectra attest to maser emission. Our 28SiO maps show the stable ring of maser spot

Rosalba Perna, Abraham Loeb

The current census of observed baryons in the local Universe is still missing a significant fraction of them according to standard Big-Bang nucleosynthesis. Numerical simulations predict that most of the missing baryons are in a hot intergalactic medium, which is difficult to observe through its X-ray emission or Sunyaev-Zel&#39;dovich effect. We show that t

Steen Hannestad

The decay of massive neutrinos to final states containing only invisible particles is poorly constrained experimentally. In this letter we describe the constraints that can be put on neutrino mass and lifetime using CMBR measurements. We find that very tight lifetime limits on neutrinos in the mass range 10 eV - 100 keV can be derived using CMBR data from up

Göran Östlin, Nils Bergvall, Jari Rönnback

Multicolour images of the starbursting metal poor blue compact galaxy ESO338-IG04 have been obtained with WFPC2/HST. In the images we find numerous point-like sources concentrated towards the main body of the galaxy, which we identify as globular cluster candidates. We show that these objects are physically associated with the galaxy and that they are spatia

M. Tosi, L. Pulone, G. Marconi, A. Bragaglia

We present CCD BVI photometry of the old open cluster Berkeley 21, one of the most distant clusters in the Galactic anticentre direction, and possibly the lowest metallicity object in the open clusters sample. Its position and metal abundance make it very important for the study of the Galactic disc. Using the synthetic Colour - Magnitude Diagram method, we

Peter G. Jonker, Rudy Wijnands, Michiel van der Klis, Dimitrios Psaltis

We have discovered two simultaneous kHz quasi-periodic oscillations (QPOs) in the Z source GX 340+0 with the Rossi X-ray Timing Explorer. The X-ray hardness-intensity and color-color diagram each show a full Z-track, with an extra limb branching off the flaring branch of the Z. Both peaks moved to higher frequencies when the mass accretion rate increased. Th

Kenji Bekki

We perform numerical simulations of galaxy mergers between star-forming and gas-rich spirals in order to explore the origin of the Fundamental Plane (FP) of elliptical galaxies. We consider particularly that the origin of the slope of the FP is essentially due to the non-homology in structure and kinematics of elliptical galaxies and accordingly investigate

H. Wu, Z. L. Zou, X. Y. Xia, Z. G. Deng

Spectroscopic observations of a sample of 73 very luminous IRAS galaxies (log(LIR/Lsun)>=11.5 for H0=50km s^{-1} Mpc^{-1},q0=0.5) from the 2Jy red- shift survey catalogue were carried out using the 2.16m telescope at the Beijing Astronomical Observatory. The observational data, including the optical images (extracted from Digital Sky Survey) and spectra for

Renee C. Kraan-Korteweg, Baerbel Koribalski, Sebastian Juraszek

About 25% of the optical extragalactic sky is obscured by the dust and stars of our Milky Way. Dynamically important structures might still lie hidden in this zone. Various approaches are presently being employed to uncover the galaxy distribution in this Zone of Avoidance (ZOA). Results as well as the different limitations and selection effects from these m

Robert Antonucci

Updates are provided on several issues related to Unified Models. A new HST spectrum of Cygnus A confirms the broad MgII emission line, and suggests a very large velocity width as seen in the polarized optical lines. Statistics of the 3CR sample are discussed, with emphasis on the role of mid-IR data to distinguish hidden quasars from &#34;nonthermal AGN&#34

R. A. Janik, M. A. Nowak, G. Papp, I. Zahed

We show that at the critical point of chiral random matrix models, novel scaling laws for the inverse moments of the eigenvalues are expected. We evaluate explicitly the pertinent microscopic spectral density, and found it in agreement with numerical calculations. We suggest that similar sum rules are of relevance to QCD at the critical temperature, and even

Roberto Fernández, Pablo A. Ferrari, Nancy L. Garcia

We present a new approach to study measures on ensembles of contours, polymers or other objects interacting by some sort of exclusion condition. For concreteness we develop it here for the case of Peierls contours. Unlike existing methods, which are based on cluster-expansion formalisms and/or complex analysis, our method is strictly probabilistic and hence

Dirk. K. Morr

Recently, inelastic neutron scattering (INS) experiments on the insulating parent compounds of high-T_c materials were analyzed to extract the value of the superexchange constant $J$. Starting point of the analysis was the nearest-neighbor Heisenberg model. Motivated by recent ARPES experiments, we consider the effects of a next-nearest neighbor hopping, $t&

Mirta S. Iriondo, Enzo O. Leguizamon, Oscar A. Reula

We study the dynamics of Einstein&#39;s equations in Ashtekar&#39;s variables from the point of view of the theory of hyperbolic systems of evolution equations. We extend previous results and show that by a suitable modification of the Hamiltonian vector flow outside the sub-manifold of real and constrained solutions, a symmetric hyperbolic system is obtaine

Romualdo Pastor-Satorras, Daniel H. Rothman

We formulate a stochastic equation to model the erosion of a surface with fixed inclination. Because the inclination imposes a preferred direction for material transport, the problem is intrinsically anisotropic. At zeroth order, the anisotropy manifests itself in a linear equation that predicts that the prefactor of the surface height-height correlations de

R. Pastor-Satorras, J. M. Rubi

We present a new model of sequential adsorption in which the adsorbing particles experience dipolar interactions. We show that in the presence of these long-range interactions, highly ordered structures in the adsorbed layer may be induced at low temperatures. The new phenomenology manifests through significant variations of the pair correlation function and

Kelvin K. S. Wu, Ofer Lahav, Martin J. Rees

New measurements of galaxy clustering and background radiations provide improved constraints on the isotropy and homogeneity of the Universe on large scales. In particular, the angular distribution of radio sources and the X-Ray Background probe density fluctuations on scales intermediate between those explored by galaxy surveys and the Cosmic Microwave Back

Paolo Zanardi, Fausto Rossi

A potential implementation of quantum-computation schemes in semiconductor-based structures is proposed. In particular, an array of quantum dots is shown to be an ideal quantum register for a noiseless information encoding. In addition to the suppression of phase-breaking processes in quantum dots due to the well-known phonon bottleneck, we show that a prope

Wen-Fa Lu

The ground, one- and two-particle states of the (1+1)-dimensional massive sine-Gordon field theory are investigated within the framework of the Gaussian wave-functional approach. We demonstrate that for a certain region of the model-parameter space, the vacuum of the field system is asymmetrical. Furthermore, it is shown that two-particle bound state can exi

M. Beneke

Recent calculations of heavy quark cross sections near threshold at next-to-next-to-leading order have found second-order corrections as large as first-order ones. We analyse long-distance contributions to the heavy quark potential in momentum and coordinate space and demonstrate that long-distance contributions in momentum space are suppressed as $Λ_{QCD}^2

Maciej Konacki, Andrzej J. Maciejewski

Since it has become possible to discovery planets orbiting nearby solar-type stars through very precise Doppler-shift measurements, the role of methods used to analyze such observations has grown significantly. The widely employed model-dependent approach based on the least-squares fit of the Keplerian motion to the radial-velocity variations can be, as we s

Raimar Wulkenhaar

We investigate the SO(10)-unification model in a Lie algebraic formulation of noncommutative geometry. The SO(10)-symmetry is broken by a 45-Higgs and the Majorana mass term for the right neutrinos (126-Higgs) to the standard model structure group. We study the case that the fermion masses are as general as possible, which leads to two 10-multiplets, four 12

Carsten Greiner, Stefan Leupold

Ill-defined pinch singularities arising in a perturbative expansion in out of equilibrium quantum field theory have a natural analogue to standard scattering theory. We explicitly demonstrate that the occurrence of such terms is directly related to Fermi&#39;s golden rule known from elementary scattering theory and is thus of no mystery. We further argue tha

Roberto Zucchini

We present a detailed algebraic study of the N=2 cohomological set--up describing the balanced topological field theory of Dijkgraaf and Moore. We emphasize the role of N=2 topological supersymmetry and $sl(2,R)$ internal symmetry by a systematic use of superfield techniques and of an $sl(2,R)$ covariant formalism. We provide a definition of N=2 basic and eq

Carsten Timm, S. M. Girvin, H. A. Fertig

The melting and magnetic disordering of the skyrmion lattice in the quantum Hall system at filling factor $ν\approx 1$ are studied. A Berezinskii-Kosterlitz-Thouless renormalization group theory is employed to describe the coupled magnetic and translational degrees of freedom. The non-trivial magnetic properties of the skyrmion system stem from the in-plane

D. V. Antonov

Making use of the duality transformation, we construct string representation for the partition function of the London limit of Abelian Higgs Model with an additional axionic term. In the lowest order of perturbation theory, this term leads to the appearance in the resulting string effective action of a new threelocal interaction between the elements of the s

Xiaofeng Guo

In deeply inelastic lepton-nucleus scattering (DIS), the average jet transverse momentum is broadened because of the multiple scattering in the nuclear medium. The size of jet broadening is proportional to the multi-parton correlation functions inside nuclei. We show that at leading order, jet broadening in DIS and nulcear enhancement in di-jet momentum imba

Satoshi Nozawa, Naoki Itoh, Yasuharu Kohyama

We extend the formalism of the relativistic thermal Sunyaev-Zel&#39;dovich effect to the system moving with a velocity beta (= v/c) with respect to the cosmic microwave background radiation. In the present formalism, the kinematic Sunyaev-Zel&#39;dovich effect for the cluster of galaxies with a peculiar velocity is derived in a straightforward manner by the

J. Berges, K. Rajagopal

We explore the phase diagram of strongly interacting matter as a function of temperature and baryon number density, using a class of models for two-flavor QCD in which the interaction between quarks is modelled by that induced by instantons. Our treatment allows us to investigate the possible simultaneous formation of condensates in the conventional quark--a

Mark Hillery, Jozef Skvarcek

The electric field in a lossless, regularly-pumped micromaser with injected atomic coherence can undergo a period 2 oscillations in the steady state. The field changes its value after a single atom passes through the micromaser cavity, but returns to its original value after a second atom travels through. We give a simple explanation for this phenomenon in t

I. Marzoli, I. Bialynicki-Birula, O. M. Friesch, A. E. Kaplan

Characteristic structures such as canals and ridges --intermode traces-- emerge in the spacetime representation of the probability distribution of a particle in a one-dimensional box. We show that the corresponding propagator already contains these structures. We relate their visibility to the factorization property of the initial wave packet.

Lu-Ming Duan, Guang-Can Guo

Collective decoherence is possible if the departure between quantum bits is smaller than the effective wave length of the noise field. Collectivity in the decoherence helps us to devise more efficient quantum codes. We present a class of optimal quantum codes for preventing collective amplitude damping to a reservoir at zero temperature. It is shown that two

J. L. Friar

Nuclear scales are discussed from the nuclear physics viewpoint. The conventional nuclear potential is characterized as a black box that interpolates nucleon-nucleon (NN) data, while being constrained by the best possible theoretical input. The latter consists of the longer-range parts of the NN force (e.g., OPEP, TPEP, the $π$-$γ$ force), which can be calcu

D. H. Lu, K. Tsushima, A. W. Thomas, A. G. Williams

In order to measure the charge form factor of the neutron, $G^n_E(Q^2)$, one needs to use a neutron bound in a nuclear target. We calculate the change in the form factor for a neutron bound in $^3He$, with respect to the free case, using several versions of the quark meson coupling model. It is found that the form factor may be suppressed by as much as 12% a

Efstratia Kalfagianni, Xiao-Song Lin

We show that for an $n$-component, $n$-bridge link and a positive integer $m$, the following is true: If the longitudes of $L$ lie in the $(m+2)$-th term of the lower central series of the link group then all the finite type invariants of orders $\leq m$ for $L$ are the same as these of the $n$-component unlink.

Jeanne Nielsen Clelland

Goursat showed that in the presence of an intermediate integral, the problem of solving a second-order Monge-Ampere equation can be reduced to solving a first-order equation, in the sense that the generic solution of the first-order equation will also be a solution of the original equation. An attempt by Hermann to give a rigorous proof of this fact contains

Joan S. Birman, Elizabeth Finkelstein

This is a review article on the Bennequin-Birman-Menasco machinery for studying embedded incompressible surfaces in 3-space via their `braid foliations&#39;. Two cases are investigated: case (1) The surface has non-empty boundary; the boundary is a knot or link which is represented as a closed braid, Case (2) The surface is closed, but it lies in the complem

Alexei Borodin

One object of interest in random matrix theory is a family of point ensembles (random point configurations) related to various systems of classical orthogonal polynomials. The paper deals with a one--parametric deformation of these ensembles, which is defined in terms of the biorthogonal polynomials of Jacobi, Laguerre and Hermite type. Our main result is a

Allan M. Sinclair, Roger R. Smith

We characterize injectivity of von Neumann algebras in terms of factoring bilinear maps as products of linear maps.

Greg Martin

It is known that there are infinitely many solutions to the inequality ϕ(30n+1)<ϕ(30n), where ϕis the familiar Euler totient function. However, there are no solutions with n<20,000,000, and computing a solution would seem to involve factoring integers with hundreds of digits. In this note, we describe how to get around the need to factor such large integers

Andrei Mudrov

We find the general solution to the twisting equation in the tensor bialgebra $T({\bf R})$ of an associative unital ring ${\bf R}$ viewed as that of fundamental representation for a universal enveloping Lie algebra and its quantum deformations. We suggest a procedure of constructing twisting cocycles belonging to a given quasitriangular subbialgebra ${\cal H

Greg Kuperberg

We give a short argument that for some C > 0, every n-dimensional Banach ball K admits a 256-round subquotient of dimension at least C n/(log n). This is a weak version of Milman&#39;s quotient of subspace theorem, which lacks the logarithmic factor.

Joan S. Birman, Rolland Trapp

The notion of a braided chord diagram is introduced and studied. An equivalence relation is given which identifies all braidings of a fixed chord diagram. It is shown that finite-type invariants are stratified by braid index for knots which can be represented as closed 3-braids. Partial results are obtained about spanning sets for the algebra of chord diagra

G. K. Savvidy

Arguing that the equation for the gonihedric string should have a generalized Dirac form, we found a new equation which corresponds to a symmetric solution of the Majorana commutation relations and has non-Jacobian form. The corresponding generalized gamma-matrices are anticommuting. Explicit formulas for the mass spectrum lead to nonzero string tension $M^{

Khazret S. Nirov

We discuss hidden symmetries of three-dimensional field configurations revealed at the one-particle level by the use of pseudoclassical particle models. We argue that at the quantum field theory level, these can be naturally explained in terms of manifest symmetries of the reduced phase space Hamiltonian of the corresponding field systems.