February 2000 arXiv papers — page 14

V. Testa, S. R. Zaggia, S. Andreon, G. Longo

We exploited the large areal coverage offered by the DPOSS to analyze the outermost regions of the galactic globular cluster M 92. Two independent photometric reduction programs (SKICAT and DAOPHOT) were used to construct a color-magnitude diagram and a surface density profile for this cluster, based on J- and F-band DPOSS plates. A strong similarity has bee

C. Vignali, M. Mignoli, A. Comastri, R. Maiolino

We present the results of a follow-up ASCA observation and multicolour optical and near-infrared photometry carried out at the 3.5-m Italian National Telescope Galileo of SAXJ1353.9+1820. This object, serendipitously discovered by BeppoSAX in the 5-10 keV band, has been spectroscopically identified as a red quasar at z=0.217. The combined X-ray and optical-i

Padeli P. Papadopoulos, Michael L. Allen

We present sensitive sub-mm imaging of the Seyfert 1 galaxy NGC 7469 at 850 $μ$m and 450 $μ$m with the Submillimetre Common User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT) and ^{12}CO J=3-2 line observations of its central starbursting region. The global dust spectrum, as constrained by the new set of sub-mm data and available 1.30 m

Laurent Eyer, Conny Aerts

A search for new gamma Dor stars was undertaken using the Hipparcos periodic variable star catalogue and the Geneva photometric database, leading to a list of 40 new candidates. We started a monitoring of the candidates which suited the observational window with the CORALIE spectrograph at the Swiss Euler Telescope for establishing a robust list of new gamma

Sara L. Ellison, Antoinette Songaila, Joop Schaye, Max Pettini

In order to ascertain the extent of metal enrichment in the Ly alpha forest, we have analysed a very high S/N spectrum of the z = 3.625 QSO Q1422+231. We find that in high column density Ly alpha clouds, the power law column density distribution function of C IV continues down to log N(C IV) = 11.7. In addition, by analysing pixel-by-pixel optical depths we

A. Polyakov, V. Rychkov

We explore gauge fields - strings duality by means of the loop equations and the zigzag symmetry. The results are striking and incomplete. Striking - because we find that the string ansatz proposed in [A.M. Polyakov, hep-th/9711002] satisfies gauge theory Schwinger-Dyson equations precisely at the critical dimension D=4. Incomplete - since we get these resul

I. J. R. Aitchison, C. D. Fosco

We present some results about the interplay between the chiral and deconfinement phase transitions in parity-conserving QED3 (with N flavours of massless 4 component fermions) at finite temperature. Following Grignani et al (Phys. Rev. D53, 7157 (1996), Nucl. Phys. B473, 143 (1996)), confinement is discussed in terms of an effective Sine-Gordon theory for th

Kayll Lake

The recent analysis of Markovic and Shapiro on the effect of a cosmological constant on the evolution of a spherically symmetric homogeneous dust ball is extended to include the inhomogeneous and degenerate cases. The histories are shown by way of effective potential and Penrose-Carter diagrams.

V. S. Berezinsky, V. I. Dokuchaev

We propose the model of a short-lived very powerful source of high energy neutrinos. It is formed as a result of the dynamical evolution of a galactic nucleus prior to its collapse into a massive black hole and formation of high-luminosity AGN. This stage can be referred to as ``pre-AGN''. A dense central stellar cluster in the galactic nucleus on th

Riccardo Argurio, Amit Giveon, Assaf Shomer

Superstrings propagating on backgrounds of the form AdS_3 x G/H are studied using the coset CFT approach. We focus on seven dimensional cosets which have a semiclassical limit, and which give rise to N=3 superconformal symmetry in the dual CFT. This is realized for the two cases AdS_3 x SU(3)/U(1) and AdS_3 x SO(5)/SO(3), for which we present an explicit con

Wim van Dam, Frederic Magniez, Michele Mosca, Miklos Santha

We consider the design of self-testers for quantum gates. A self-tester for the gates F_1,...,F_m is a classical procedure that, given any gates G_1,...,G_m, decides with high probability if each G_i is close to F_i. This decision has to rely only on measuring in the computational basis the effect of iterating the gates on the classical states. It turns out

Masanao Ozawa

In order to construct a measure of entanglement on the basis of a ``distance'' between two states, it is one of desirable properties that the ``distance'' is nonincreasing under every completely positive trace preserving map. Contrary to a recent claim, this letter shows that the Hilbert-Schmidt distance does not have this property.

C. P. Sun

It is shown that, through a super-radiant Rayleigh scattering, a strong far off-resonant pump laser applied to a Bose-Einstein condensates(BEC) can induce a non-demolition coupling of the many-mode quantized vacuum field to the BEC. This effective interaction will force the total system of the BEC plus the light field to evolve from a factorized initial stat

M. A. Lisa, E895 Collaboration

We present preliminary results of the first pion interferometry (HBT) excitation function at intermediate AGS energies. The beam energy evolution of the correlations' dependence on mT, centrality, and emission angle with respect to the reaction plane are discussed. Comparisons with predictions of the RQMD cascade model are made.

Xiaochao Xu, Kapil M. S. Bajaj, Guenter Ahlers

We present measurements of the Nusselt number $\cal N$ as a function of the Rayleigh number $R$ in cylindrical cells with aspect ratios $0.5 \leq Γ\equiv D/d \leq 12.8$ ($D$ is the diameter and $d$ the height). We used acetone with a Prandtl number $σ= 4.0$ for $10^5 \alt R \alt 4\times10^{10}$. A fit of a powerlaw ${\cal N} = {\cal N}_0 R^{γ_{eff}}$ over li

Nik. A. Tyurin

In this paper we define a new category of almost complex riemannian 4- manifolds and discuss some basic properties of such pseudo symplectic manifolds. Some motivation based on the Seiberg - Witten theory is imposed.

Andrew Kricker

In this note we reconsider a familiar result in Vassiliev knot theory - that the coefficients of the Alexander-Conway polynomial determine the top row of the Kontsevich integral - from the point of view of Kazuo Habiro's clasper theory. We observe that in this setting the calculation reflects the topology of the universal cyclic covering space of a clasp

Melvyn B. Nathanson

Let A be a set of positive integers with gcd(A) = 1, and let p_A(n) be the partition function of A. Let c = π\sqrt(2/3). Let α> 0. It is proved that log p_A(n) ~ c\sqrt(αn) if and only if the set A has asymptotic density α.

Masaaki Yoshida

An explicit projective embedding of the moduli space of marked cubic surfaces is given. This embedding is equivariant under the Weyl group of type E6. The image is defined by a system of linear and cubic equations. To express the embedding in a most symmetric way, the target would be 79-dimensional, however the image lies in a 9-dimensional linear subspace.

H. Mehrez, Jeremy Taylor, Hong Guo, Jian Wang

Spin-coherent quantum transport in carbon nanotube magnetic tunnel junctions was investigated theoretically. A spin-valve effect is found for metallic, armchair tubes, with a magneto-conductance ratio ranging up to 20%. Because of the finite length of the nanotube junctions, transport is dominated by resonant transmission. The magnetic tunnel junctions are f

J. C. Flores

A finite phase-coherence time $τ_ϕ^{meas}$ emerges from iterative measurement onto a quantum system. For a rapid sequence, the phase-coherence time is found explicitly. For the stationary charge conduction problem, it is bounded. At all order, in the time-interval of measurements, we propose a general expression for $τ_ϕ^{meas}$.

Y. Levinson, O. Entin-Wohlman, P. Woelfle

The acoustoelectric current induced by a surface acoustic wave (SAW) in a ballistic quantum point contact is considered using a quantum approach. We find that the current is of the "pumping" type and is not related to drag, i.e. to the momentum transfer from the wave to the electron gas. At gate voltages corresponding to the plateaus of the quantized

Chandan Dasgupta, Oriol T. Valls

We report numerical results for the phase diagram in the density-disorder plane of a hard sphere system in the presence of quenched, random, pinning disorder. Local minima of a discretized version of the Ramakrishnan-Yussouff free energy functional are located numerically and their relative stability is studied as a function of the density and the strength o

Stefano Fabris, Anthony T. Paxton, Michael W. Finnis

We describe an empirical, self-consistent, orthogonal tight-binding model for zirconia, which allows for the polarizability of the anions at dipole and quadrupole levels and for crystal field splitting of the cation d orbitals. This is achieved by mixing the orbitals of different symmetry on a site with coupling coefficients driven by the Coulomb potentials

Yu-Wen Lee, Yu-Li Lee

Using one-dimensional spin-orbital model as a typical example of quantum spin systems with richer symmetries, we study the effect of an isolated impurity on its low energy dynamics in the gapless phase through bosonization and renormalization group methods. In the case of internal impurities, depending on the symmetry, the boundary fixed points can be either

J. Kaupuzs

We consider the Ginzburg-Landau phase transition model with O(n) symmetry (i.e., the n-vector model) which includes a quenched randomness, i.e., a random temperature disorder. We have proven rigorously that within the diagrammatic perturbation theory the quenched randomness does not change the critical exponents at n tending to 0, which is in contrast to the

T. Fouchet, E. Lellouch, B. Bezard, H. Feuchtgruber

We have analysed the ISO-SWS spectrum of Jupiter in the 12-16 micron range, where several hydrocarbons exhibit rovibrational bands. Using temperature information from the methane and hydrogen emissions, we derive the mixing ratios (q) of acetylene and ethane at two independent pressure levels. For acetylene, we find $q=(8.9^{+1.1}_{-0.6})\times10^{-7}$ at 0.

I. Negueruela, P. Reig, M. H. Finger, P. Roche

Using the RossiXTE experiment, we detect weak X-ray emission from the recurrent Be/X-ray transient A 0535+26 at a time when the optical counterpart V725 Tau displayed H-alpha in absorption, indicating the absence of a circumstellar disc. The X-ray radiation is strongly modulated at the 103.5-s pulse period of the neutron star, confirming that it originates f

S. M. Molnar, M. Birkinshaw

We estimate the contributions to the cosmic microwave background radiation (CMBR) power spectrum from the static and kinematic Sunyaev-Zel'dovich (SZ) effects, and from the moving cluster of galaxies (MCG) effect. We conclude, in agreement with other studies, that at sufficiently small scales secondary fluctuations caused by clusters provide important co

Arnon Dar, Alvaro DeRújula

Recent measurements of the spin-down rates of soft gamma ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) have been interpreted as evidence that these objects are ``magnetars'': neutron stars spinning down by magnetic dipole radiation, but with a magnetic field two orders of magnitude larger than that of ordinary neutron stars. We discuss the

Barbara Simovic, Denis Jerome, Laszlo Forro

133Cs and 13C-NMR have been used to study the electronic properties of the polymerized phase of CsC60 at ambient and under hydrostatic pressure. The salient result of this study is the finding of fluctuations in the local field at 133Cs site which are independent of the applied pressure and due to thermally activated changes in the local electronic environme

Anton Alekseev, Andrei Bytsko

We introduce the notion of a monodromy for gauge fields with vanishing curvature on the noncommutative torus. Similar to the ordinary gauge theory, traces of the monodromies define noncommutative Wilson lines. Our main result is that these Wilson lines are invariant under the Seiberg-Witten map changing the deformation parameter of the noncommutative torus.

Tohru Eguchi, Yuji Sugawara

We study the type II superstring theory on the background $\br^{d-1,1}\times X_n$, where $X_n$ is a Calabi-Yau $n$-fold ($2n+d=10$) with an isolated singularity, by making use of the holographically dual description proposed by Giveon-Kutasov-Pelc (hep-th/9907178). We compute the toroidal partition functions for each of the cases $d=6,4,2$, and obtain manife

Masao Jinzenji

In this paper, we propose another characterization of the generalized mirror transformation on the quantum cohomology rings of general type projective hypersurfaces. This characterics is useful for explicit determination of the form of the generalized mirror transformation. As applications, we rederive the generalized mirror transformation up to $d=3$ ration

Miloslav Znojil

PT symmetric complex potential V(r) = - r^4 + i a r^3 + b r^2 + i c r + i d/r + e/r^2 is studied. Arbitrarily large multiplets of its closed bound-state solutions with real energies are shown obtainable quasi-exactly (i.e., with a certain relationship between their charges and energies) from a single underlying finite-dimensional secular equation.

A. A. Kokin

The one-dimensional homonuclear periodic array of nuclear spins I = 1/2, owing to hyperfine interaction of nuclear spins with electronic magnetic moments in antiferromagnetic structure, is considered. The neighbor nuclear spins in such array are opposite oriented and have resonant frequencies determined by hyperfine interaction constant, applied magnetic fie

S. W. Hong, B. T. Kim

Pion-nucleus scattering cross sections are calculated by solving a Schrödinger equation reduced from the Klein-Gordon equation. Local potentials are assumed, and phenomenological potential parameters are searched energy-dependently for $π^{-} + ^{12}$C system so as to reproduce not only elastic differential cross sections but also total elastic, reaction and

Omar Foda, Trevor A. Welsh

We provide further boson-fermion q-polynomial identities for the `finitised' Virasoro characters χ^{p, p'}_{r,s} of the Forrester-Baxter minimal models M(p, p'), for certain values of r and s. The construction is based on a detailed analysis of the combinatorics of the set P^{p, p'}_{a, b, c}(L) of q-weighted, length-L Forrester-Baxter paths,

Melvyn B. Nathanson

Let A be a nonempty finite set of relatively prime positive integers, and let p_A(n) denote the number of partitions of n with parts in A. An elementary arithmetic argument is used to obtain an asymptotic formula for p_A(n).

A. A'Campo-Neuen, J. Hausen

We give examples for existence and non-existence of categorical quotients for algebraic group actions in the categories of algebraic varieties and prevarieties. All our examples are subtorus actions on toric varieties.

F. Anselmo, J. Ellis, D. V. Nanopoulos, G. Volkov

We present an inductive algebraic approach to the systematic construction and classification of generalized Calabi-Yau (CY) manifolds in different numbers of complex dimensions, based on Batyrev's formulation of CY manifolds as toric varieties in weighted complex projective spaces associated with reflexive polyhedra. We show how the allowed weight vector

Fumihiko Ukegawa

We review recent experimental results on spectroscopy and lifetime of bottom and charm hadrons.

H. P. Buechler, H. G. Katzgraber, G. Blatter

We present a new approach to calculate the attractive long-range vortex-vortex interaction of the van der Waals type present in anisotropic and layered superconductors. The mapping of the statistical mechanics of two-dimensional charged bosons allows us to define a Casimir problem: Two half spaces of vortex matter separated by a gap of width R are mapped to

Igor Tupitsyn, Bernard Barbara

We review the present state of theory and experiments on the quantum tunneling of magnetization in mesoscopic spin systems. Most attention is paid to the relaxation of magnetization in the molecular complexes Mn12 and Fe8. The role of the thermostat (phonons, nuclear spins, dipolar fields) is studied.

Michael Wilkinson

This paper extends earlier work on the definition of Wannier functions for Bloch electrons in a magnetic field. Extensions to irrational as well as rational magnetic fields are defined, and their properties investigated. The results are used to give a generalisation of the Peierls effective Hamiltonian which is valid when the magnetic flux per unit cell is c

Carlo Baccigalupi, Francesca Perrotta, Sabino Matarrese

We describe the observable features of the recently proposed Extended Quintessence scenarios on the Cosmic Microwave Background (CMB) anisotropy spectra. In this class of models a scalar field $ϕ$, assumed to provide most of the cosmic energy density today, is non-minimally coupled to the Ricci curvature scalar $R$. We implement the linear theory of cosmolog

A. Loinger

There are reference frames for which both stars of binary radio-pulsar PSR1913+16 are at rest. As a consequence, PSR1913+16 does not emit gravity waves. (If the accelerated bodies should send out a gravitational radiation, they would represent a class of physically privileged systems. But this is forbidden by general relativity.)

X. Kong, X. Zhou, J. S. Chen, F. Z. Cheng

In this paper, we present a multi-color photometric study of the nearby spiral galaxy M81, using images obtained with the Beijing Astronomical Observatory 60/90 cm Schmidt Telescope in 13 intermediate-band filters from 3800 to 10000Å. The observations cover the whole area of M81 with a total integration of 51 hours from February 1995 to February 1997. This p

M. Eracleous, R. M. Sambruna, R. F. Mushotzky

We present the results of hard-X-ray observations of four broad-line radio galaxies (BLRGs) with the Rossi X-Ray Timing Explorer (RXTE). The original motivation behind the observations was to search for systematic differences between the BLRGs and their radio-quiet counterparts, the Seyfert galaxies. We do, indeed, find that the Fe K-alpha lines and Compton

A. V. Filippenko

I present an overview of optical observations (mostly spectra) of Type II supernovae. SNe II are defined by the presence of hydrogen, and exhibit a very wide variety of properties. SNe II-L tend to show evidence of late-time interaction with circumstellar material. SNe IIn are distinguished by relatively narrow emission lines with little or no P-Cygni absorp

Francois Schweizer

Gravitational interactions and mergers are shaping and reshaping galaxies throughout the observable universe. While observations of interacting galaxies at low redshifts yield detailed information about the processes at work, observations at high redshifts suggest that interactions and mergers were much more frequent in the past. Major mergers of nearby disk

J. Bjoraker, Y. Hosotani

A continuum of monopole, dyon and black hole solutions exist in the Einstein-Yang-Mills theory in asymptotically anti-de Sitter space. Their structure is studied in detail. The solutions are classified by non-Abelian electric and magnetic charges and the ADM mass. The stability of the solutions which have no node in non-Abelian magnetic fields is established

Scott A. Hughes

As shown by Teukolsky, the master equation governing the propagation of weak radiation in a black hole spacetime can be separated into four ordinary differential equations, one for each spacetime coordinate. (``Weak'' means the radiation's amplitude is small enough that its own gravitation may be neglected.) Unfortunately, it is difficult to accu

Ashok Muthukrishnan, C. R. Stroud,

We develop a multi-valued logic for quantum computing for use in multi-level quantum systems, and discuss the practical advantages of this approach for scaling up a quantum computer. Generalizing the methods of binary quantum logic, we establish that arbitrary unitary operations on any number of d-level systems (d > 2) can be decomposed into logic gates that

Antonio Dobado, Maria J. Herrero, Siannah Penaranda

We study the heavy Higgs sector of the MSSM composed of the H^\pm, H^0 and A^0 particles in the so-called decoupling limit where m_{A^0} >> m_Z. By integrating out these heavy Higgs particles to one-loop, we compute the effective action for the electroweak gauge bosons and find out that, in the decoupling limit, all the heavy Higgs effects can be absorbed in

F. M. Cucchietti, H. M. Pastawski

In order to perform quantum Hamiltonian dynamics minimizing localization effects, we introduce a quasi-one dimensional tight-binding model whose mean free path is smaller than the size of the sample. This one, in turn, is smaller than the localization length. We study the return probability to the starting layer of the system by means of direct diagonalizati

Martin Treiber, Ansgar Hennecke, Dirk Helbing

We present data from several German freeways showing different kinds of congested traffic forming near road inhomogeneities, specifically lane closings, intersections, or uphill gradients. The states are localized or extended, homogeneous or oscillating. Combined states are observed as well, like the coexistence of moving localized clusters and clusters pinn

K. B. Vijaya Kumar, Judith A. McGovern, Michael C. Birse

We present a calculation of the fourth-order (NLO) contribution to spin-dependent Compton scattering in heavy-baryon chiral perturbation theory, and we give results for the four spin polarisabilities. No low-energy constants, except for the anomalous magnetic moments of the nucleon, enter at this order. For forward scattering the fourth-order piece of the sp

C. Baccigalupi, L. Bedini, C. Burigana, G. De Zotti

The Independent Component Analysis (ICA) algorithm is implemented as a neural network for separating signals of different origin in astrophysical sky maps. Due to its self-organizing capability, it works without prior assumptions on the signals, neither on their frequency scaling, nor on the signal maps themselves; instead, it learns directly from the input

Igor Kondrashuk

Slavnov-Taylor identities have been applied to perform explicitly the renormalization procedure for the softly broken N=1 SYM. The result is in accordance with the previous results obtained at the level of supergraph technique.

Melvyn B. Nathanson

Let S be an abelian semigroup, written additively. Let A be a finite subset of S. We denote the cardinality of A by |A|. For any positive integer h, the sumset hA is the set of all sums of h not necessarily distinct elements of A. We define 0A = {0}. If A_1,...,A_r, and B are finite sumsets of A and h_1,...,h_r are nonnegative integers, the sumset h_1A + ...

J. Trampetic

A current status report on radiative inclusive and exclusive B decays is presented.

V. V. Kiselev, A. E. Kovalsky, A. K. Likhoded

In the framework of three-point QCD sum rules, the form factors for the semileptonic decays of B_c --> B_s(B_s^*) l νare calculated with account for the Coulomb-like alpha_s/v-corrections in the heavy quarkonium. The generalized relations due to the spin symmetry of HQET/NRQCD for the form factors are derived at the recoil momentum close to zero. The nonlept

Alessandro Campa, Andrea Giansanti, Daniele Moroni

The canonical partition function of a system of rotators (classical X-Y spins) on a lattice, coupled by terms decaying as the inverse of their distance to the power alpha, is analytically computed. It is also shown how to compute a rescaling function that allows to reduce the model, for any d-dimensional lattice and for any alpha<d, to the mean field (alpha=

Licia Verde, Alan F. Heavens, Sabino Matarrese

We present a theoretical and exact analysis of the bispectrum of projected galaxy catalogues. The result can be generalized to evaluate the projection in spherical harmonics of any 3D bispectrum and therefore has applications to cosmic microwave background and gravitational lensing studies. By expanding the 2D distribution of galaxies on the sky in spherical

Elisabeth Vangioni-Flam, Alain Coc, Michel Casse

We update the Big Bang Nucleosynthesis calculations on the basis of the recent NACRE compilation. The average values of the calculated abundances of light nuclei do not differ significantly from that obtained using the previous Fowler&#39;s compilation. ${^7}Li$ is slightly depressed at high baryon to photon ratio $η$. The main uncertainty concerns the $D(p,

Keita Kishigi, Yasumasa Hasegawa

We theoretically study how the coexistent state of the charge density wave and the spin density wave in the one-dimensional quarter filled band is enhanced by magnetic fields. We found that when the correlation between electrons is strong the spin density wave state is suppressed under high magnetic fields, whereas the charge density wave state still remains

K. Zarembo

The effective action for Goldstone bosons in the color-flavor locking phase of dense QCD is analyzed. Interaction terms and higher derivatives in the effective action appear to be controlled by different scales. At energies of order of the superconducting gap, the derivative expansion breaks down, while interactions still remain suppressed. The effective act

Jorge Vitorio Pereira

We prove the following theorem for Holomorphic Foliations in compact complex kaehler manifolds: if there is a compact leaf with finite holonomy, then every leaf is compact with finite holonomy. As corollary we reobtain stability theorems for compact foliations in Kaehler manifolds of Edwards-Millett-Sullivan and Hollman.

Curtis Manning, Daniel Stern, Hyron Spinrad, Andrew J. Bunker

In the course of our ongoing search for serendipitous high-redshift Lyman alpha (LyA) Emissionin deep archival Keck spectra, we discovered two very high equivalent width (W_{obs} ~ 450A, 2-sigma) LyA emission line candidates at z ~3 in a moderate dispersion (R~1200) spectrogram. Both lines have low velocity dispersions (sigma_v ~ 60 km/s) and deconvolved rad

S. B. Giddings, E. Katz, L. Randall

A treatment of linearized gravity is given in the Randall-Sundrum background. The graviton propagator is found in terms of the scalar propagator, for which an explicit integral expression is provided. This reduces to the four-dimensional propagator at long distances along the brane, and provides estimates of subleading corrections. Asymptotics of the propaga

Somshubhro Bandyopadhyay

We present two optimal methods of teleporting an unknown qubit using any pure entangled state. We also discuss how such methods can also have succesful application in quantum secret sharing with pure multipartite entangled states.

Ben Yu-Kuang Hu

Submitted to &#34;Notes and Discussions&#34; in American Journal of Physics.

D. Davesne, Y. J. Zhang, G. Chanfray, J. Wambach

We discuss medium modifications of the unitarized pion-pion interaction in the nuclear medium. We incorporate both the effects of chiral symmetry restoration and the influence of collective nuclear pionic modes, originating from the p-wave coupling of the pion to delta-hole configurations. We show how the resulting strong enhancement of the sigma-meson spect

P. SchucK, Z. Aouissat, G. Chanfray, J. Wambach

The influence of a dropping sigma-meson mass on previously calculated in-medium pion-pion correlations in the J=I=0 (sigma-meson) channel is investigated. It is found that the invariant-mass distribution around the vacuum threshold experiences a further strong enhancement over and above the standard many-body effects. The relevance of this result for the the

Magnus Johansson, Serge Aubry

We investigate the long-time evolution of weakly perturbed single-site breathers (localized stationary states) in the discrete nonlinear Schroedinger (DNLS) equation. The perturbations we consider correspond to time-periodic solutions of the linearized equations around the breather, and can be either (i) spatially localized, or (ii) spatially extended. For c

Kestutis Staliunas

It is proposed that the spatial (and temporal) patterns spontaneously appearing in dissipative systems maximize the energy flow through the pattern forming interface. In other words - the patterns maximize the entropy growth rate in an extended conservative system (consisting of the pattern forming interface and the energy bathes). The proposal is supported

Senya Shlosman

We present the geometric solutions of the various extremal problems of statistical mechanics and combinatorics. Together with the Wulff construction, which predicts the shape of the crystals, we discuss the construction which exhibits the shape of a typical Young diagram and of a typical skyscraper.

J. Dobaczewski

It is shown how to construct a basis in which two arbitrary complex antisymmetric matrices C and C&#39; acquire simultaneously canonical forms. The present construction is not restricted by any conditions on properties of the C^+C&#39; matrix. Canonical bases pertaining to the generator-coordinate-method treatment of many-fermion systems are discussed.

I. Vlasenko

We consider general Morse-Smale diffeomorphisms on a closed orientable two-dimentional surface. In this paper it is proved that the complete topological invariant of Morse-Smale diffeomorphisms is finite, the algorithm of the construction of the complete topological invariant in explicit form is given and necessary and sufficient conditions of topological co

D. Abramovich, K. Matsuki, S. Rashid

The recent two proofs for the (weak) factorization theorem for birational maps, one by Włodarczyk and the other by Abramovich-Karu-Matsuki-Włodarczyk rely on the results of Morelli. The former uses the process for $π$-desingularization (the most subtle part of Morelli&#39;s combinatorial algorithm), while the latter uses the strong factorization of toric (to

Andrej Dujella

Let n be a nonzero integer and assume that a set S of positive integers has the property that xy+n is a perfect square whenever x and y are distinct elements of S. In this paper we find some upper bounds for the size of the set S. We prove that if |n| <= 400 then |S| <= 32, and if |n| > 400 then |S| < 267.81 log|n| (log log|n|)^2. The question whether there

Joseph Bernstein, Igor Frenkel, Mikhail Khovanov

We identify the Grothendieck group of certain direct sum of singular blocks of the highest weight category for sl(n) with the n-th tensor power of the fundamental (two-dimensional) sl(2)-module. The action of U(sl(2)) is given by projective functors and the commuting action of the Temperley-Lieb algebra by Zuckerman functors. Indecomposable projective functo

Andrei Okounkov

It is a basic property of the entropy in statistical physics that is concave as a function of energy. The analog of this in representation theory would be the concavity of the logarithm of the multiplicity of an irreducible representation as a function of its highest weight. We discuss various situations where such concavity can be established or reasonably

Kenji Matsuki

This is an expanded version of the notes for the lectures given by the author at RIMS in the summer of 1999 to give a detailed account of the proof for the (weak) factorization theorem of birational maps by Abramovich-Karu-Matsuki-Włodarczyk.

Chang S. Chan, Ori J. Ganor, Morten Krogh

We construct chiral N=1 gauge theories in 4D by compactifying the 6D Blum-Intriligator (1,0) theories of 5-branes at $A_k$ singularities on $T^2$ with a nontrivial bundle of the global U(1) symmetry of these theories.

G. Veneziano

A review is attempted of physical motivations, theoretical and phenomenological aspects, as well as outstanding problems, of the pre-big bang scenario in string cosmology.

A. Bassetto, L. Griguolo, F. Vian

$QCD_2$ with fermions in the adjoint representation is invariant under $SU(N)/Z_N$ and thereby is endowed with a non-trivial vacuum structure (k-sectors). The static potential between adjoint charges, in the limit of infinite mass, can be therefore obtained by computing Wilson loops in the pure Yang-Mills theory with the same non-trivial structure. When the

I. Bakas, A. Brandhuber, K. Sfetsos

Supersymmetric domain-wall solutions of maximal gauged supergravity are classified in 4, 5 and 7 dimensions in the presence of non-trivial scalar fields taking values in the coset SL(N, R)/SO(N) for N=8, 6 and 5 respectively. We use an algebro-geometric method based on the Christoffel-Schwarz transformation, which allows for the characterization of the solut

George Sterman, Werner Vogelsang

Parton distribution functions are determined by the comparison of finite-order calculations with data. We briefly discuss the interplay of higher order corrections and PDF determinations, and the use of soft-gluon resummation in global fits.

G. Moreau, E. Perez, G. Polesello

The resonant production of sneutrinos at the LHC via the R-parity violating couplings $ł&#39;_{ijk} L_i Q_j D^c_k$ is studied through its three-leptons signature. A detailed particle level study of signal and background is performed using a fast simulation of the ATLAS detector. Through the full reconstruction of the cascade decay, a model-independent and pr

Cedric Deffayet, Jean-Philippe Uzan

In presence of a magnetic field, photons can mix with any particle having a two-photon vertex. In theories with large compact extra-dimensions, there exists a hierachy of massive Kaluza-Klein gravitons that couple to any photon entering a magnetic field. We study this mixing and show that, in comparison with the four dimensional situation where the photon co

Gi-Chol Cho

We review constraints on additional Z&#39; bosons predicted in supersymmetric (SUSY) E_6 models from electroweak experiments - Z-pole experiments, mW measurements and the low-energy neutral current (LENC) experiments. Four representative models - χ,ψ, η, νmodels - are studied in some detail. We find that the improved data of parity violation in cesium atom,

L. Bergstrom

The evidence for the existence of dark matter in the universe is reviewed. A general picture emerges, where both baryonic and non-baryonic dark matter is needed to explain current observations. In particular, a wealth of observational information points to the existence of a non-baryonic component, contributing between around 20 and 40 percent of the critica

Kari Enqvist

In the MSSM, cosmological scalar field condensates formed along flat directions of the scalar potential (Affleck-Dine condensates) are typically unstable with respect to formation of Q-balls, a type of non-topological soliton. I discuss the creation and growth of the quantum seed fluctuations which catalyse the collapse of the condensate. In D-term inflation

Joao P. Silva, Lincoln Wolfenstein

It is expected that, within the next three years, the determination of the CKM matrix elements with the least theoretical uncertainty will arise from the measurements of CP violation in B_d --> J/ψK_S decays and from Bs-Bsbar mixing. If there is significant new physics in Bs-Bsbar mixing, then those experiments will not yield the correct values for the CKM m

B. Alles, J. J. Alonso, C. Criado, M. Pepe

Reply to comment appeared on hep-lat/9912014.

M. Gockeler, R. Horsley, D. Petters, D. Pleiter

A numerical study of quenched QCD for light quarks is presented using O(a) improved fermions. Particular attention is paid to the possible existence and determination of quenched chiral logarithms. A `safe&#39; region to use for chiral extrapolations appears to be at and above the strange quark mass.

M Berg, M Bradley

We consider exact solutions generated by the inverse scattering technique, also known as the soliton transformation. In particular, we study the class of simple real pole solutions. For quite some time, those solutions have been considered interesting as models of cosmological shock waves. A coordinate singularity on the wave fronts was removed by a transfor

A. K. Raychaudhuri

It is shown that if the timelike eigenvector of the Ricci tensor be hypersurface orthogonal so that the space time allows a foliation into space sections then the space average of each of the scalar that appear in the Raychaudhuri equation vanishes provided the strong energy condition holds good. This result is presented in the form of a singularity theorem.