June 2002 arXiv papers — page 8

Y. Yayon, A. Esser, M. Rappaport, V. Umansky

Variations in the width of a quantum well (QW) are known to be a source of broadening of the exciton line. Using low temperature near-field optical microscopy, we have exploited the dependence of exciton energy on well-width to show that in GaAs QWs, these seemingly random well-width fluctuations actually exhibit well-defined order -- strong long-range corre

Gun Sang Jeon, Jong Soo Lim, Hyun Jin Kim, M. Y. Choi

We consider a two-dimensional fully frustrated Josephson-junction array, which is driven uniformly by oscillating currents. As the temperature is lowered, there emerges a dynamic phase transition to an ordered state with nonzero dynamic order parameter for small currents. The transition temperature decreases monotonically with the driving amplitude, approach

K. Kohno, T. Tosaki, S. Matsushita, B. Vila-Vilaro

The Nobeyama Millimeter Array (NMA) has been used to make aperture synthesis CO(1-0) observations of the post-starburst galaxy NGC 5195. CO(1-0) and HCN(1-0) observations of NGC 5195 using the Nobeyama 45 m telescope are also presented. High-resolution (1".9 x 1".8 or 86 pc x 81 pc at D = 9.3 Mpc) NMA maps show a strong concentration of CO emission t

J. Mikolajewska, E. A. Kolotilov, S. Yu. Shugarov, B. F. Yudin

We present and analyze quiescent UBVRI light curves of the classical symbiotic binary YY Her. We show that the secondary minimum, which is clearly visible only in the quiescent VRI light curves, is due to ellipsoidal variability of the red giant component. Our simple light curve analysis, by fitting of the Fourier cosine series, resulted in a self-consistent

K. Kohno, S. Matsushita, B. Vila-Vilaro, S. K. Okumura

An imaging survey of CO(1-0), HCN(1-0), and HCO$^+$(1-0) lines in the centers of nearby Seyfert galaxies has been conducted using the Nobeyama Millimeter Array and the RAINBOW interferometer. Preliminary results reveal that 3 Seyferts out of 7 show abnormally high HCN/CO and HCN/HCO$^+$ ratios, which cannot occur even in nuclear starburst galaxies. We sugges

L. V. Shalyapina, A. V. Moiseev, V. A. Yakovleva

We present our observations of the galaxy UGS 5600 with a long-slit spectrograph (UAGS) and a multi-pupil field spectrograph (MPFS) using the 6-m telescope at Special Astrophysical Observatory. Radial-velocity fields of the stellar and gaseous components were constructed for the central region and inner ring of the galaxy. We proved the existence of two almo

Jozsef Garai

It is suggested that at the melting temperature the thermal phonon vibration is in self-resonance with the lattice vibration of the surface atomic/molecular layer. This self resonance occurs at a well defined temperature and triggers the detachment of the atomic/molecular sheet or platelets from the surface of the crystal. Thermodynamic data of five substanc

A. Recati, P. O. Fedichev, W. Zwerger, P. Zoller

We investigate the physical properties of quasi-1D quantum gases of fermion atoms confined in harmonic traps. Using the fact that for a homogeneous gas, the low energy properties are exactly described by a Luttinger model, we analyze the nature and manifestations of the spin-charge separation. Finally we discuss the necessary physical conditions and experime

Hiroyuki Hata, Sanefumi Moriyama

We reexamine the oscillator construction of the D25-brane solution and the tachyon fluctuation mode of vacuum string field theory given previously. Both the classical solution and the tachyon mode are found to violate infinitesimally their determining equations in the level cut-off regularization. We study the effects of these violations on physical quantiti

John N. Bahcall, Eli Waxman

The energy spectra of ultra high energy cosmic rays reported by the AGASA, Fly's Eye, Haverah Park, HiRes, and Yakutsk experiments are all shown to be in agreement with each other for energies below 10^{20} eV (after small adjustments, within the known uncertainties, of the absolute energy scales). The data from HiRes, Fly's Eye, and Yakutsk are consistent w

Di Li, Paul F. Goldsmith

We have used the Arecibo telescope to carry out an survey of 31 dark clouds in the Taurus/Perseus region for narrow absorption features in HI ($λ$ 21cm) and OH (1667 and 1665 MHz) emission. We detected HI narrow self--absorption (HINSA) in 77% of the clouds that we observed. HINSA and OH emission, observed simultaneously are remarkably well correlated. Spect

Volker Springel, Lars Hernquist

Employing hydrodynamic simulations of structure formation in a LCDM cosmology, we study the history of cosmic star formation from the "dark ages" at redshift z~20 to the present. In addition to gravity and ordinary hydrodynamics, our model includes radiative heating and cooling of gas, star formation, supernova feedback, and galactic winds. By making

N. G. Zhang, C. L. Henley

We consider a Hubbard-like model of strongly-interacting spinless fermions and hardcore bosons on a square lattice, such that nearest neighbor occupation is forbidden. Stripes (lines of holes across the lattice forming antiphase walls between ordered domains) are a favorable way to dope this system below half-filling. The problem of a single stripe can be ma

J. L. F. Barbon

We consider gauge theories with multitrace deformations in the context of certain AdS/CFT models with explicit breaking of conformal symmetry and supersymmetry. In particular, we study the standard four-dimensional confining model based on the D4-brane metric at finite temperature. We work in the self-consistent Hartree approximation, which becomes exact in

Spencer R. Klein, Joakim Nystrand, Ramona Vogt

Heavy quarks are copiously produced in ultra-peripheral heavy ion collisions. In the strong electromagnetic fields, c c-bar and b b-bar are produced by photonuclear and two-photon interactions; hadroproduction can occur in grazing interactions. We present the total cross sections, quark transverse momentum and rapidity distributions, as well as the Q Q-bar i

Konrad Banaszek, Ian A. Walmsley

We propose a design for a photon counting detector capable of resolving multiphoton events. The basic element of the setup is a fiber loop, which traps the input field with the help of a fast electrooptic switch. A single weakly coupled avalanche photodiode is used to detect small portions of the signal field extracted from the loop. We analyze the response

Emilio Santos

The main argument against the assumption that quantum fluctuations of the electromagnetic field are real is that they do not activate photon detectors. In order to met this objection I study several models of photon counter compatible with the reality of the fluctuations. The models predict a nonlinear dependence of the counting rate with the light intensity

Antonina N. Fedorova, Michael G. Zeitlin

The consideration of dynamics of relativistic beams/particles is based on variational approach to rational (in dynamical variables) approximation for equations of motions. It allows to control contribution from each scale of underlying multiscales and represent solutions via exact nonlinear eigenmodes expansions. Our approach is based on methods provided pos

Antonina N. Fedorova, Michael G. Zeitlin

We consider modeling for strong-strong beam-beam interactions beyond preceding linearized/perturbative methods such as soft gaussian approximation or FMM (HFMM) etc. In our approach discrete coherent modes, discovered before, and possible incoherent oscillations appear as a result of multiresolution/multiscale fast convergent decomposition in the bases of hi

Antonina N. Fedorova, Michael G. Zeitlin

We consider some reduction from nonlinear Vlasov-Maxwell equation to rms/rate equations for second moments related quantities. Our analysis is based on variational wavelet approach to rational (in dynamical variables) approximation. It allows to control contribution from each scale of underlying multiscales and represent solutions via multiscale exact nonlin

Antonina N. Fedorova, Michael G. Zeitlin

We consider the applications of a numerical-analytical approach based on multiscale variational wavelet technique to the systems with collective type behaviour described by some forms of Vlasov-Poisson/Maxwell equations. We calculate the exact fast convergent representations for solutions in high-localized wavelet-like bases functions, which correspond to un

Antonina N. Fedorova, Michael G. Zeitlin

We consider an application of modification of our variational-wavelet approach to some nonlinear collective model of beam/plasma physics: Vlasov/Boltzmann-like reduction from general BBGKY hierachy related to modeling of propagation of intense charged particle beams in high-intensity accelerators and transport systems. We use fast convergent multiscale varia

Antonina N. Fedorova, Michael G. Zeitlin

Fast and efficient numerical-analytical approach is proposed for modeling complex collective behaviour in accelerator/plasma physics models based on BBGKY hierarchy of kinetic equations. Our calculations are based on variational and multiresolution approaches in the bases of polynomial tensor algebras of generalized coherent states/wavelets. We construct the

Bao-An Li

High energy heavy-ion collisions are proposed as a novel means to obtain information about the high density ({\rm HD}) behaviour of nuclear symmetry energy. Within an isospin-dependent hadronic transport model using phenomenological equations of state ({\rm EOS}) for dense neutron-rich matter, it is shown that the isospin asymmetry of the HD nuclear matter f

Antonina N. Fedorova, Michael G. Zeitlin

We apply variational-wavelet approach for constructing multiscale high-localized eigenmodes expansions in different models of nonlinear waves. We demonstrate appearance of coherent localized structures and stable pattern formation in different collective dynamics models.

Joachim Nzotungicimpaye

We study the second central extension of the (1+1) Aristotle Lie.We find that the first central extension admit four orbits on the dual of second central extension of the (1+1) Aristotle Lie group.The generic orbit is characterised by a Hooke's constant k and a yank y.If the physics of the orbit is studied with respect the evolution in time,it represents

M. Faber, A. N. Ivanov

We show that the boson field representation of the massless fermion fields, suggested by Morchio, Pierotti and Strocchi in J. Math. Phys. 33, 777 (1992) for the operator solution of the massless Thirring model, agrees completely with the existence of the chirally broken phase in the massless Thirring model revealed in EPJC 20, 723 (2001) and hep-th/0112183,

V. G. Krivokhijine, A. V. Kotikov

We reanalyze deep inelastic scattering data of BCDMS Collaboration by including proper cuts of ranges with large systematic errors. We perform also the fits of high statistic deep inelastic scattering data of BCDMS, SLAC, NM and BFP Collaborations taking the data separately and in combined way and find good agreement between these analyses. We extract the va

Leszek Roszkowski

Where is the long--awaited one? A supersymmetric neutralino has been a favored candidate for the WIMP dark matter but, so far, it has not been found. One way to locate it is to identify where it can be hiding in the vast supersymmetric parameter space. A combination of theoretical, experimental and cosmological constraints leads to remarkably well--defined a

J. Tojo, I. Alekseev, M. Bai, B. Bassalleck

The analyzing power for proton-carbon elastic scattering in the coulomb-nuclear interference region of momentum transfer, $9.0\times10^{-3}<-t<4.1\times10^{-2}$ (GeV/$c)^{2}$, was measured with a 21.7 GeV/$c$ polarized proton beam at the Alternating Gradient Synchrotron of Brookhaven National Laboratory. The ratio of hadronic spin-flip to non-flip amplitude,

Daniel Green, W. G. Unruh

Using the extension of the standard Hawking-Hartle prescription for defining a wave function for the universe, we show that it is possible, given a suitable form for the scalar field potential, to have the universe begin at its largest size and thereafter contract, with the growth of perturbations proceeding from small, at the largest size, to largest when t

Yu. N. Gornostyrev, M. I. Katsnelson, A. V. Kravtsov, A. V. Trefilov

A computer simulation of thermofluctuation nucleation of kinks on dislocations and their dynamics is carried out in the framework of two-dimensional (2D) Frenkel-Kontorova model. It is shown that at relatively low temperatures and applied stresses the kinks can appear as a result of developing instability of phonon modes localized in the vicinity of the disl

K. T. McCarthy, A. F. Hebard, S. B. Arnason

The magnetic field dependence of the capacitance of Pd-AlOx-Al thin-film structures has been measured. The observed quadratic dependence of capacitance on magnetic field is consistent with a theoretical model that includes the effect of a spin-dependent electrochemical potential on electron screening in the paramagnetic Pd. This spin-dependent electrochemica

H. Yanagihara, M. B. Salamon

As in such 2D systems as the XY model, topological (or singularity point) defects are thought to play a crucial role in the phase transitions of 3D spin systems. In double exchange (DE) ferromagnets, the conduction electrons are strongly coupled with core spins through Hund&#39;s rule, and in the presence of non-trivial spin texture, acquire a Berry phase co

J. R. Petta, D. C. Ralph

We have measured the full angular dependence, as a function of the direction of magnetic field, for the Zeeman splitting of individual energy states in copper nanoparticles. The g-factors for spin splitting are highly anisotropic, with angular variations as large as a factor of five. The angular dependence fits well to ellipsoids. Both the principal-axis dir

Brian M. Andersen, P. Hedegaard

We set up a simple transfer matrix formalism to study the existence of bound states at interfaces and in junctions between antiferromagnets and d-wave superconductors. The well-studied zero energy mode at the {110} interface between an insulator and a d-wave superconductor is spin split when the insulator is an antiferromagnet. This has as a consequence that

R. Shen, Z. M. Zheng, S. Liu, D. Y. Xing

We discuss the possibility of coexistence of spin-singlet superconductivity and ferromagnetism in a model where the same electrons are assumed responsible for both of them. Our calculations include both zero and finite momentum pairing states with both s-wave and d-wave pairing symmetry. Under the mean-field approximation, the thermodynamic potential of the

Anaël Lemaître

Typical properties of glassy materials are shown to be captured by a mean-field free-volume theory. Relaxation processes are supposed to be free-volume activated, and different entropy barriers are associated with density relaxation and shear motion. Free-volume time logarithmic relaxation, Kohlrausch-Williams-Watts, and power law viscosity result from the n

S. Hill, M. M. Mola, J. S. Qualls

A microwave cavity perturbation technique is used to probe the interlayer electrodynamics within the vortex state of the organic superconductor kappa-(BEDT-TTF)2Cu(NCS)2. A Josephson plasma mode is observed which is extremely sensitive to correlations in the locations of vortices in adjacent layers and may, therefore, be used to gauge collective effects betw

F. Thomsen, A. Nordlund

We have performed 3-D numerical magnetohydrodynamic (MHD) jet experiments to study the instabilities associated with strongly toroidal magnetic fields and determine if such magnetic configurations in jets are as unstable as similar situations are found to be in the laboratory and in analytical estimates. A perfectly conducting Keplerian disc with fixed densi

Volker Springel, Lars Hernquist

We present a model for star formation and supernova feedback that describes the multi-phase structure of star forming gas on scales that are typically not resolved in cosmological simulations. Our approach includes radiative heating and cooling, the growth of cold clouds embedded in an ambient hot medium, star formation in these clouds, feedback from superno

S. L. Lumsden, M. G. Hoare, R. D. Oudmaijer, D. Richards

The combination of mid-infrared data from the MSX satellite mission and ground-based near-infrared photometry is used to characterise the properties of the mid-infrared population of the Galactic plane. The colours of the youngest sources still heavily embedded within their natal molecular clouds are in general different from evolved stars shrouded within th

Asantha Cooray

The halo approach to large scale structure provides a physically motivated model to understand clustering properties of galaxies. An important aspect of the halo model involves a description on how galaxies populate dark matter halos or what is now called the halo occupation distribution. We discuss a way in which clustering information, especially in the no

B. Z. Dai, G. Z. Xie, Z. J. Jiang, D. C. Mei

We present the optical light curve for the gamma-ray blazar PKS 1510-089 with a significant variability of 2.0 mag within about 41 minutes in the R band which is the most violently rapid variability detected in our optical monitoring campaign operating since 1982. In the framework of the relativistic beaming model, the central supermassive black hole mass of

C. A. Terrero-Escalante

It is argued that the order of the analytic expressions for the calculation of the primordial perturbations from inflation exerts a strong influence upon the results of the analysis of observables dynamics based on these expressions and, therefore, upon some predictions sometimes taken for granted as generic for the inflationary scenario.

Jason Tumlinson, J. Michael Shull, Aparna Venkatesan

The first stars hold intrinsic interest for their uniqueness and for their potential importance to galaxy formation, chemical enrichment, and feedback on the intergalactic medium (IGM). The metal-free composition of the first stars restricts the stellar energy source to proton-proton burning rather than the more efficient CNO cycle. Consequently they are hot

Aparna Venkatesan, Jason Tumlinson, J. Michael Shull

We examine the significance of the first metal-free stars (Pop III) for the cosmological reionization of HI and HeII. These stars have unusually hard spectra, with the integrated ionizing photon rates from a Pop III stellar cluster for HI and HeII being 1.6 and $10^5$ times stronger respectively than those from a Pop II cluster. For the currently favored cos

Korkut Bardakci, Charles B. Thorn

We develop an approximation scheme for our worldsheet model of the sum of planar diagrams based on mean field theory. At finite coupling the mean field equations show a weak coupling solution that resembles the perturbative diagrams and a strong coupling solution that seems to represent a tensionless soup of field quanta. With a certain amount of fine-tuning

Jeremy Michelson

A pp-wave solution to 11-dimensional supergravity is given with precisely 26 supercharges. Its uniqueness and the absence of 11-dimensional pp-waves which preserve (precisely) 28 or 30 supercharges is discussed. Compactification on a spacelike circle gives a IIA configuration with all 26 of the supercharges. For this compactification, D0 brane charge does no

Evgeny I. Buchbinder, Ron Donagi, Burt A. Ovrut

The non-perturbative superpotential generated by a heterotic superstring wrapped once around a genus-zero holomorphic curve is proportional to the Pfaffian involving the determinant of a Dirac operator on this curve. We show that the space of zero modes of this Dirac operator is the kernel of a linear mapping that is dependent on the associated vector bundle

C. Alexandrou, Ph. de Forcrand, A. Tsapalis

Gauge-invariant equal-time correlation functions are calculated in lattice QCD within the quenched approximation and with two dynamical quark species. These correlators provide information on the shape and multipole moments of the pion, the rho, the nucleon and the $Δ$.

D. S. Gorbunov, P. G. Tinyakov, S. V. Troitsky

The Z-burst mechanism invoked to explain ultra-high energy cosmic rays is severely constrained by measurements of the cosmic gamma-ray background by EGRET. We discuss the case of optically thick sources and show that jets and hot spots of active galaxies cannot provide the optical depth required to suppress the photon flux. Other extragalactic accelerators (

A. J. Skinner, M. E. Davenport, B. E. Kane

We suggest an architecture for quantum computing with spin-pair encoded qubits in silicon. Electron-nuclear spin-pairs are controlled by a dc magnetic field and electrode-switched on and off hyperfine interaction. This digital processing is insensitive to tuning errors and easy to model. Electron shuttling between donors enables multi-qubit logic. These hydr

Gary Gibbons, Sean A. Hartnoll

We explore a classical instability of spacetimes of dimension $D>4$. Firstly, we consider static solutions: generalised black holes and brane world metrics. The dangerous mode is a tensor mode on an Einstein base manifold of dimension $D-2$. A criterion for instability is found for the generalised Schwarzschild, AdS-Schwarzschild and topological black hole s

R. Guimera, A. Arenas, A. Diaz-Guilera, F. Vega-Redondo

The problem of searchability in decentralized complex networks is of great importance in computer science, economy and sociology. We present a formalism that is able to cope simultaneously with the problem of search and the congestion effects that arise when parallel searches are performed, and obtain expressions for the average search cost--written in terms

P. C. Fragile, G. J. Mathews, J. Poirier, T. Totani

We explore several models which might be proposed to explain recent possible detections of high-energy (TeV) gamma rays in association with low-energy gamma-ray bursts (GRBs). Likely values (and/or upper limits) for the source energies in low- and high-energy gamma rays and hadrons are deduced for the burst sources associated with possible TeV gamma-ray dete

Dmitri V. Efremov, Richard A. Klemm

We calculate the static and dynamic properties of single crystal, single molecule magnets consisting of equal spin $S=1/2$ or 5/2 dimers. The spins in each dimer interact with each other via the Heisenberg exchange interaction and with the magnetic induction ${\bf B}$ via the Zeeman interaction, and interdimer interactions are negligible. For antiferromagnet

H. G. Dosch, P. Gauron, B. Nicolescu

The (lns)**2 behaviour of total cross-sections, first obtained by Heisenberg 50 years ago, receives now increased interest both on phenomenological and theoretical levels. In this paper we present a modification of the Heisenberg&#39;s model in connection with the presence of glueballs and we show that it leads to a realistic description of all existing hadr

Georgios Katomeris, Franck Selva, Jean-Louis Pichard

In 1969, Andreev and Lifshitz have conjectured the existence of a supersolid phase taking place at zero temperature between the quantum liquid and the solid. In this and a succeeding paper, we re-visit this issue for a few polarized electrons (spinless fermions) interacting via a U/r Coulomb repulsion on a two dimensional L * L square lattice with periodic b

J. Páramos, O. Bertolami, T. A. Girard, P. Valko

We examine the consequences of a cubic term addition to the mean-field potential of Ginzburg-Landau theory to describe first order superconductive phase transitions. Constraints on its existence are obtained from experiment, which are used to assess its impact on topological defect creation. We find no fundamental changes in either the Kibble-Zurek or Hindma

Ernesto Lozano-Tellechea, Patrick Meessen, Tomas Ortin

We show how all known N=2, d=4,5,6 maximally supersymmetric vacua (Hpp-waves and aDSxS solutions) are related through dimensional reduction/oxidation preserving all the unbroken supersymmetries. In particular we show how the N=2, d=5 family of vacua (which are the near-horizon geometry of supersymmetric rotating black holes) interpolates between aDS_2xS^3 an

David M. J. Calderbank, Michael A. Singer

This paper is concerned with the construction of special metrics on non-compact 4-manifolds which arise as resolutions of complex orbifold singularities. Our study is close in spirit to the construction of the hyperkaehler gravitational instantons, but we focus on a different class of singularities. We show that any resolution X of an isolated cyclic quotien

F. Intravaia, S. Maniscalco, J. Piilo, A. Messina

The heating of trapped ions due to the interaction with a {\it quantized environment} is studied {\it without performing the Born-Markov approximation}. A generalized master equation local in time is derived and a novel theoretical approach to solve it analytically is proposed. Our master equation is in the Lindblad form with time dependent coefficients, thu

Cristina Manuel, Stanislaw Mrowczynski

We solve the collisionless transport equations of a quark-gluon plasma interacting through mean chromodynamic fields. The system is assumed to be translation invariant in one or more space-time directions. We present exact solutions that hold if the vector gauge fields in the direction of the translation invariance commute with their covariant derivatives. W

C. Barraud, J-F. Olive, J. P. Lestrade, J-L. Atteia

We present a spectral analysis of 35 GRBs detected with the HETE-2 gamma-ray detectors (the FREGATE instrument) in the energy range 7-400 keV. The GRB sample analyzed is made of GRBs localized with the Wide Field X-ray Monitor onboard HETE-2 or with the GRB Interplanetary Network. We derive the spectral parameters of the time-integrated spectra, and present

S. Moretti

We show how a statistically significant signal of heavy charged Higgs bosons of a general Two-Higgs Doublet Model produced in association with tau-neutrino pairs can be established at future Linear Colliders in the $H^+\to t\bar b\to 4$ jet decay channel. This signature is particularly relevant in the kinematic configuration $\sqrt s\lsim2 M_{H^\pm}$, when t

Takahiro Miura, Tetsuo Shindou, Eiichi Takasugi

We discuss the neutrino mass matrix which predicts zero or small values of |V_{13}| in MSSM and found the inequality, sin^2 2theta_{12} <= sin^2 2theta_sol, where sin^2 2theta_{12} is the mixing angle at M_R scale and sin^2 2theta_{sol} is the value determined by the solar neutrino oscillation. This constraint says that the model which predicts a larger valu

S. Moretti, D. P. Roy

The correlation between the two $τ$-polarisations is predicted to be opposite $(+-/-+)$ for the $H/A \to τ^+τ^-$ signal, while it corresponds to the same sign combinations for the Drell-Yan $(++/--)$ and $t \bar t$ $(--)$ backgrounds. We show that this correlation can serve as a distinctive test to confirm the presence of the MSSM Higgs bosons $H$ and $A$ in

M. N. Dubinin, A. V. Semenov

We consider the two-Higgs-doublet model with explicit CP-violation, where the effective Higgs potential is not CP-invariant at the tree-level. Three neutral Higgs bosons of the model are the mixtures of CP-even and CP-odd bosons which exist in the CP-conserving limit of the theory. The mass spectrum and tree-level couplings of the neutral Higgs bosons to gau

Anke Knauf, Michael Meyer-Hermann, Gerhard Soff

We present a new estimate of the exponent governing the small-x behaviour of the nonsinglet structure function g_1(p-n) derived under the assumption that the Bjorken Sum Rule is valid. We use the world wide average of alpha_s and the NNNLO QCD corrections to the Bjorken Sum Rule. The structure function g_1(NS) is found to be clearly divergent for small x.

A. H. Hoang, R. Hofmann

A prescription for the short-distance expansion of Euclidean current correlators based on a delocalized modification of the multipole expansion of perturbative short-distance coefficient functions is proposed that appreciates the presence of nonlocal physics in the nonperturbative QCD vacuum. This expansion converges better than the local Wilson OPE, which i

Sergei Sakovich

For the Bakirov system, which is known to possess only one higher-order local generalized symmetry, we explicitly find a zero-curvature representation containing an essential parameter.

Evgeny N. Bulgakov, Pavel Exner, Konstantin N. Pichugin, Almas F. Sadreev

We study bound states of the two-dimensional Helmholtz equations with Dirichlet boundary conditions in an open geometry given by two straight leads of the same width which cross at an angle $θ$. Such a four-terminal junction with a tunable $θ$ can realized experimentally if a right-angle structure is filled by a ferrite. It is known that for $θ=90^o$ there i

Edward Teo, K. F. Wong

The quantum interest conjecture of Ford and Roman asserts that any negative-energy pulse must necessarily be followed by an over-compensating positive-energy one within a certain maximum time delay. Furthermore, the minimum amount of over-compensation increases with the separation between the pulses. In this paper, we first study the case of a negative-energ

Hongya Liu

Exact global solutions of five-dimensional cosmological models compactified on a $S_1/Z_2$ orbifold with two 3-branes are presented, and evolution of a simple model is studied. It is found that on all 4D spacetime hypersurfaces, except a singular one, the expanding universe was started not from a big bang but from a big bounce, and before the bounce the univ

G. P. Berman, F. Borgonovi, G. Celardo, F. M. Izrailev

In this paper we analyze the dynamics in a spin-model of quantum computer. Main attention is paid to the dynamical fidelity (associated with dynamical errors) of an algorithm that allows to create an entangled state for remote qubits. We show that in the regime of selective resonant excitations of qubits there is no any danger of quantum chaos. Moreover, in

Wilhelm I. Fushchych

In this note we shall construct, in the framework of relativistic quantum mechanics, the Poincare-invariant motion equations with realistic mass spectra. These equations describe a system with mass spectra of the form $m^2=a^2+b^2 s(s+1)$, where a and b are arbitrary parameters. Such equations are obtained by a reduction of the motion equation for two partic

A. Messina, S. Maniscalco, A. Napoli

The spectacular experimental results of the last few years in cavity quantum electrodynamics and trapped ions research has led to very high level laboratory performances. Such a stimulating situation essentially stems from two decisive advancements. The first is the invention of reliable protocols for the manipulation of single atoms. The second is the abili

Wilhelm I. Fushchych

The purpose of the present note is to propose, in the framework of relativistic quantum mechanics, a new Poincare-invariant equation for two particles with masses m_1, m_2 and spin s_1=s_2=1/2. It is a first-order linear differential equation for the eight-component wave function. With the help of this equation the description of the motion of two-particle s

Wilhelm I. Fushchych

In this note we show that there exists a new set of operators {Q} (this set is different from the operators which satisfy the Lie algebra of the Poincare group P(1,3) with respect to which the Dirac and Maxwell equations are invariant. We shall give the detailed proof of our assertions only for the Dirac equation, since for the Maxwell equations all the asse

Akihisa Tomita, Kazuo Nakamura

A photon detector combining the two avalanche photon diodes (APD) has been demonstrated for qubit discrimination in 1550 nm. Spikes accompanied with the signals in gated-mode were canceled by balanced output from the two APDs. The spike cancellation enabled one to reduce the threshold in the discriminators, and thus the gate pulse voltage. The dark count pro

M. J. Berryman, A. Allison, D. Abbott

We use the inter-word spacing technique, that Ortuno et al devised for analyzing DNA.We develop this idea further for classifying ancient texts.

Ulf Saalmann, Jan M Rost

The effect of intense X-ray laser interaction on argon clusters is studied theoretically with a mixed quantum/classical approach. In comparison to a single atom we find that ionization of the cluster is suppressed, which is in striking contrast to the observed behavior of rare-gas clusters in intense optical laser pulses. We have identified two effects respo

R. Ball, R. L. Dewar, H. Sugama

The structural properties of an economical model for a confined plasma turbulence governor are investigated through bifurcation and stability analyses. A close relationship is demonstrated between the underlying bifurcation framework of the model and typical behavior associated with low- to high-confinement transitions such as shear flow stabilization of tur

B. J. King, N. V. Mokhov, N. Simos, R. J. Weggel

A conceptual design is presented for a high power pion production target for muon colliders and neutrino factories that is based around a rotating metal band.

R. Schmidt, A. Trzcinska, T. Czosnyka, T. von Egidy

The x-ray cascade from antiprotonic atoms was studied for 106Cd, 116Cd, 112Sn, 116Sn, 120Sn, and 124Sn. Widths and shifts of the levels due to strong interaction were deduced. Isotopic effects in the Cd and Sn isotopes are clearly seen. The results are used to investigate the nucleon density in the nuclear periphery. The deduced neutron distributions are com

N. de Sereville, A. Coc, C. Angulo, M. Assuncao

The 18F(p,alpha) reaction was recognized as one of the most important for gamma ray astronomy in novae as it governs the early 511 keV emission. However, its rate remains largely uncertain at nova temperatures. A direct measurement of the cross section over the full range of nova energies is impossible because of its vanishing value at low energy and of the

T. Papenbrock, T. H. Seligman

Collective modes of interacting many-body systems can be related to the motion on classically invariant manifolds. We introduce suitable coordinate systems. These coordinates are Cartesian in position and momentum space. They are collective since several components vanish for motion on the invariant manifold. We make a connection to Zickendraht&#39;s collect

I. Ojima

A unified scheme for treating generalized superselection sectors is proposed on the basis of the notion of selection criteria to characterize states of relevance to each specific domain in quantum physics, ranging from the relativistic quantum fields in the vacuum situations with unbroken and spontaneously broken internal symmetries, through equilibrium and

Herbert Clemens

This paper studies the Hilbert scheme of a curve on a complete-intersection K-trivial threefold, in the case in which the curve is unobstructed in the ambient variety in which the threefold lives. The basic result is that the obstruction theory of the curve is completely determined by the scheme-theoretic Abel-Jacobi mapping. Several applications of this fac

Mohamed Maghfoul

Nous generalisons la theorie de la K-moyennabilite au cas d&#39;un unitaire multiplicatif regulier V. Nous montrons que si (H,V,U) est un systeme de Kac K-moyennable, alors pour toute S-algebre A, les algebres $ A\times_{m}\hat S$ (produit croise maximal) et $ A\times \hat S$ (produit croise reduit) sont KK-equivalentes ou S est la $C^*$-algebre de Hopf redu

Delfim F. M. Torres

We study, in a unified way, the following questions related to the properties of Pontryagin extremals for optimal control problems with unrestricted controls: i) How the transformations, which define the equivalence of two problems, transform the extremals? ii) How to obtain quantities which are conserved along any extremal? iii) How to assure that the set o

Alex Kuronya

In this paper we present a divisorial valuation with irrational volume using an algebro-geometric construction.

Oliver Johnson

The Poincare constant R(Y) of a random variable Y relates the L2 norm of a function g and its derivative g&#39;. Since R(Y) - Var(Y) is positive, with equality if and only if Y is normal, it can be seen as a distance from the normal distribution. In this paper we establish a best possible rate of convergence of this distance in the Central Limit Theorem. Fur

Mark M. Malamud, Semen M. Malamud

In the first section we provide a solution to the M. G. Krein problem about an inner description of the space $L_2(Σ,H).$ In the second section we introduce the multiplicity function for an operator measure. Making use of the description of the space $L_2(Σ,H)$ we establish the correctness of the definition and give a criterion for a spectral measure to be a

Hiroshi Mizukawa, Hiro-Fumi Yamada

An expression is given for the plethysm $p_{2}\circ S_{\square}$, where $p_{2}$ is the power sum of degree two and $S_{\square}$ is the Schur function indexed by a rectangular partition. The formula can be well understood from the viewpoint of the basic representation of the affine Lie algebra of type $A_{2}^{(2)}$.

P. Deift, X. Zhou

The authors use steepest descent ideas to obtain a priori $L^p$ estimates for solutions of Riemann-Hilbert Problems. Such estimates play a crucial role, in particular, in analyzing the long-time behavior of solutions of the perturbed nonlinear Schrödinger equation on the line.

Wadim Zudilin

A general hypergeometric construction of linear forms in (odd) zeta values is presented. The construction allows to recover the records of Rhin and Viola for the irrationality measures of $ζ(2)$ and $ζ(3)$, as well as to explain Rivoal&#39;s &#34;infinitely-many&#34; result (math.NT/0008051) and to prove that at least one of the four numbers $ζ(5)$, $ζ(7)$,

Alexander Braverman, David Kazhdan

Let $F$ be a local non-archimedian field and let $G$ be a group of points of a split reductive group over $F$. For a parabolic subgroup $P$ of $G$ we set $X_P=G/[P,P]$. For any two parabolics $P$ and $Q$ with the same Levi component $M$ we construct an explicit unitary isomorphism $L^2(X_P)\to L^2(X_Q)$ (which depends on a choice of an additive character of

Ziv Ran

This revision contains some additional corrections and references, including a reference to Zeuthen suggested by Kleiman. For possible subsequent revisions, check http://math.ucr.edu/~ziv/papers/1nodal.pdf