August 2002 arXiv papers — page 12

W. M. Stuckey

Motivated by Wheeler's bottom up pregeometry, we introduce a pregeometric approach that does not assume Wheeler's probability amplitudes for establishing spacetime neighborhoods. Rather, a non-trivial metric is produced via the concept of a uniformity base, which is generated with discrete topological groups over some arbitrary fundamental, denumerab

Joseph Y. Halpern, Ron van der Meyden, Moshe Y. Vardi

Sound and complete axiomatizations are provided for a number of different logics involving modalities for knowledge and time. These logics arise from different choices for various parameters. All the logics considered involve the discrete time linear temporal logic operators `next' and `until' and an operator for the knowledge of each of a number of

Alina Andreica

The theme of symbolic computation in algebraic categories has become of utmost importance in the last decade since it enables the automatic modeling of modern algebra theories. On this theoretical background, the present paper reveals the utility of the parameterized categorical approach by deriving a multivariate polynomial category (over various coefficien

W Chen

The frequency-dependent attenuation of broadband acoustics is often confronted in many different areas. However, the related time domain simulation is rarely found in literature due to enormous technical difficulty. The currently popular relaxation models with the presence of convolution operation require some material parameters which are not readily availa

Peter Van Roy, Per Brand, Denys Duchier, Seif Haridi

Oz is a multiparadigm language that supports logic programming as one of its major paradigms. A multiparadigm language is designed to support different programming paradigms (logic, functional, constraint, object-oriented, sequential, concurrent, etc.) with equal ease. This article has two goals: to give a tutorial of logic programming in Oz and to show how

Wei Cheng, Shang-Fen Ren

Electronic States of Si and Ge QDs of 5 to 3127 atoms with saturated shapes in a size range of 0.57 to 4.92 nm for Si and 0.60 to 5.13 nm for Ge are calculated by using an empirical tight binding model combined with the irreducible representations of the group theory. The results are compared with those of Si and Ge quantum dots with spherical shape. The eff

Ron Lifshitz, M. C. Cross

The response of a coupled array of nonlinear oscillators to parametric excitation is calculated in the weak nonlinear limit using secular perturbation theory. Exact results for small arrays of oscillators are used to guide the analysis of the numerical integration of the model equations of motion for large arrays. The results provide a qualitative explanatio

C. Daly, J. Zhang, J. B. Sokoloff

Using an adiabatic approximation method, which searches for Tomlinson model-like instabilities for a simple but still realistic model for two crystalline surfaces in the extremely light contact limit, with mobile molecules present at the interface, sliding relative to each other, we are able to account for the virtually universal occurrence of "dry frict

V. F. Kozhevnikov, M. Diwekar, V. P. Kamaev, J. Shi

Gallium metallic photonic crystals with 100% filling factor have been fabricated via infiltration of liquid gallium into opals of 300-nm silica spheres using a novel high pressure-high temperature technique. The electrical resistance of the Ga-opal crystals was measured at temperatures from 10 to 280 K. The data obtained show that Ga-opal crystals are metall

H. P. Büchler, G. Blatter, W. Zwerger

An atomic gas subject to a commensurate periodic potential generated by an optical lattice undergoes a superfluid--Mott insulator transition. Confining a strongly interacting gas to one dimension generates an instability where an arbitrary weak potential is sufficient to pin the atoms into the Mott state; here, we derive the corresponding phase diagram. The

Jeffrey R. Errington, Pablo G. Debenedetti, Salvatore Torquato

We conduct a numerical investigation of structural order in the shifted-force Lennard-Jones system by calculating metrics of translational and bond-orientational order along various paths in the phase diagram covering equilibrium solid, liquid, and vapor states. A series of non-equilibrium configurations generated through isochoric quenches, isothermal compr

Dietrich Stauffer

The model of Bonabeau explains the emergence of social hierarchies from the memory of fights in an initially egalitarian society. Introducing a feedback from the social inequality into the probability to win a fight, we find a sharp transition between egalitarian society at low population density and hierarchical society at high population density.

Z. F. Wang, B. W. Southern, D. A. Lavis

By introducing a chiral term into the Hamiltonian of the 3-state Potts model on a triangular lattice additional symmetries are achieved between the clockwise and anticlockwise states and the ferromagnetic state. This model is investigated using Monte Carlo methods. We investigate the full phase diagram and find evidence for a line tricritical points separati

T. Droese, R. Besseling, P. Kes, C. Morais Smith

We study the depinning transition of a driven chain-like system in the presence of frustration and quenched disorder. The analysis is motivated by recent transport experiments on artificial vortex-flow channels in superconducting thin films. We start with a London description of the vortices and then map the problem onto a generalized Frenkel-Kontorova model

A. Görlitz, T. L. Gustavson, A. E. Leanhardt, R. Löw

We have investigated the properties of Bose-Einstein condensates of sodium atoms in the upper hyperfine ground state in a purely optical trap. Condensates in the high-field seeking $| F=2, m_F=-2>$ state were created from initially prepared $| F=1,m_F=-1>$ condensates using a one-photon microwave transition at 1.77 GHz. The condensates were stored in a large

Stefan Thurner, Nikolaus Wick, Rudolf Hanel, Roland Sedivy

We propose a model for cell migration where epithelial cells are able to detect trajectories of other cells and try to follow them. As cells move along in 2D cell culture, they mark their paths by loosing tiny parts of cytoplasm. Any cell moving on a surface where other cells have moved before faces a network of cell trajectories, which it tries to restrict

J. Lopez, O. F. de Lima, P. N. Lisboa-Filho, F. M. Araujo-Moreira

We studied the magnetization as a function of temperature and magnetic field in the compounds Nd0.5Sr0.5MnO3, Nd0.5Ca0.5MnO3, Sm0.5Ca0.5MnO3, Dy0.5Ca0.5MnO3 and Ho0.5Ca0.5MnO3. Ferromagnetic, antiferromagnetic and charge ordering transition in our samples agreed with previous reports. The intrinsic magnetic moments of Nd3+, Sm3+, Dy3+ and Ho3+ ions experienc

Jack Lidmar

Recently, Aji and Goldenfeldt [Phys. Rev. Lett. 87, 197003 (2001), cond-mat/0105622] put forward an explanation for the value of the dynamic critical exponent z observed in certain Monte Carlo simulations of the superconducting phase transition in zero magnetic field. In this Comment, we point out that their analysis is based on incorrect assumptions regardi

T. Kleimann, J. Stockburger, M. Sassetti, B. Kramer

We investigate discrepancies between recent experimental results on transport through one-dimensional quantum dots and universal power laws predicted by an idealized Luttinger Liquid description. The temperature dependence of Coulomb blockade peaks in one-dimensional quantum dots obeys non-universal power-laws from which different values of the interaction s

Gen Tatara, Hiroshi Kohno

We show that a spontaneous electric current is induced in a nano-scale conducting ring just by putting three ferromagnets. The current is a direct consequence of the non-commutativity of the spin algebra, and is proportional to the non-coplanarity (chirality) of the magnetization vectors. The spontaneous current gives a natural explanation to the chirality-d

B. Damski, L. Santos, E. Tiemann, M. Lewenstein

We show that by loading a Bose-Einstein condensate (BEC) of two different atomic species into an optical lattice, it is possible to achieve a Mott-insulator phase with exactly one atom of each species per lattice site. A subsequent photo-association leads to the formation of one heteronuclear molecule with a large electric dipole moment, at each lattice site

Holger Schanz

The reaction matrix of a cavity with attached waveguides connects scattering properties to properties of a corresponding closed billiard for which the waveguides are cut off by straight walls. On the one hand this matrix is directly related to the S-matrix, on the other hand it can be expressed by a spectral sum over all eigenfunctions of the closed system.

Alan M. Watson

This paper describes a lossy method for compressing raw images produced by CCDs or similar devices. The method is very simple: lossy quantization followed by lossless compression using general-purpose compression tools such as gzip and bzip2. A key feature of the method is that compressed images can be converted to FITS files simply by decompressing with gun

T. M. Glassman, J. E. Larkin, D. Lafrenière

We report here on a sample of resolved, infrared images of galaxies at z~0.5 taken with the 10-m Keck Telescope's Adaptive Optics (AO) system. We regularly achieve a spatial resolution of 0.05'' and are thus able to resolve both the disk and bulge components. We have extracted morphological information for ten galaxies and compared their properti

V. V. Flambaum

A recent paper [DDL] claims that the increase of the proton electric charge e leads to a (forbidden) decrease of black hole entropy, therefore, possible evidence for variation of $α=e^2/\hbar c$ [alpha] must be interpreted as a decrease of the speed of light. We argue that purely theoretical consideration of black holes possibly cannot give any model-indepen

Howard E. Bond, Richard L. White, Robert H. Becker, M. Sean O'Brien

We have identified the 1.4 GHz radio source FIRST J102347.6+003841 (hereafter FIRST J1023+0038) with a previously unknown 17th-mag Galactic cataclysmic variable (CV). The optical spectrum resembles that of a magnetic (AM Herculis- or DQ Herculis-type) CV. Five nights of optical CCD photometry showed variations on timescales of minutes to hours, along with ra

S. D. Van Dyk, P. M. Garnavich, A. V. Filippenko, P. Hoeflich

From Hubble Space Telescope images with 0.05" resolution we identify four stars brighter than V=25 mag within 2.5" of SN 1993J in M81 which contaminated previous ground-based brightness estimates for the supernova progenitor. Correcting for the contamination, we find that the energy distribution of the progenitor is consistent with that of an early K

Jeremy Bailin, Matthias Steinmetz

(Abridged) We investigate how galactic disks react to external tidal torques. We calculate the strength and radial dependence of torques on disks that arise from a misalignment between the disk and the main axis system of a flattened dark matter halo. We find that except for in the very inner regions, the torques are well-described by a power law of the form

Thomas S. Statler, Brian R. McNamara

We present Chandra observations of the young elliptical galaxy NGC 1700. The X-ray isophotes are highly flattened between semimajor axes of 30 and 80 arcseconds, reaching a maximum ellipticity of approximately 0.65 at 60 arcsec (15 kpc). The surface brightness profile in the spectrally soft, flattened region is shallower than that of the starlight, indicatin

Shiv S. Kumar

The processes of star formation are fundamentally different from those of planet formation. Since the mass of a very-low-mass object alone doesn't allow us to uniquely determine its basic nature, we have to look at its other characteristics, such as its motion, its age, its atmospheric composition, its internal structure and composition, etc., in order t

V. D. Ivanov, J. Borissova, P. Pessev, G. R. Ivanov

A systematic search of the 2MASS point source catalog, covering 47% of the sky, was carried out aiming to reveal any hidden globular clusters in our Galaxy. Eight new star clusters were discovered by a search algorithm based on finding peaks in the apparent stellar surface density, and a visual inspection of their vicinities yielded additional two. They all

Jennifer A. Johnson, Michael Bolte

We report Sr, Pd and Ag abundances for a sample of metal-poor field giants and analyze a larger sample of Y, Zr, and Ba abundances. The [Y/Zr] and [Pd/Ag] abundance ratios are similar to those measured for the r-process-rich stars CS 22892-052 and CS 31082-001. The [Pd/Ag] ratio is larger than predicted from the solar-system r-process abundances. The constan

D. E. Welty, E. B. Jenkins, J. C. Raymond, C. Mallouris

We combine UV spectra obtained with the HST/GHRS echelle, IMAPS, and Copernicus to study the abundances and physical conditions in the predominantly ionized gas seen at high (-105 to -65 km/s) and intermediate velocities (-60 to -10 km/s) toward zeta Ori. We have high resolution (FWHM ~ 3.3-4.5 km/s) and/or high S/N spectra for at least two significant ions

V. Damgov, D. Gotchev, E. Spedicato, A. Del Popolo

We present some non-standard approaches to the N-body problem in an attempt to overcome its epistemological limits. We provide, in a preliminary way, not-ordinary insights and breakthroughs.

G. Hebrard, N. F. Allard, I. Hubeny, S. Lacour

We present new theoretical calculations of the total line profiles of Lyman alpha and Lyman beta which include perturbations by both neutral hydrogen AND protons and all possible quasi-molecular states of H_2 and H_2^+. They are used to improve theoretical modeling of synthetic spectra for cool DA white dwarfs. We compare them with FUSE observation of G231-4

Q. Daniel Wang, Fangjun Lu, Cornelia C. Lang

We have examined Chandra observations of the recently discovered X-ray thread G0.13-0.11 in the Galactic center Radio Arc region. Part of the {\sl Chandra} data was studied by Yusef-Zadeh, Law, & Wardle (2002), who reported the detection of 6.4-keV line emission in this region. We find, however, that this line emission is {\sl not} associated with G0.13-0.11

Michael R. Corbin, William D. Vacca

We present deep U, V and I band images of the "ultracompact" blue dwarf galaxy POX 186 obtained with the Planetary Camera 2 of the Hubble Space Telescope. We have also obtained a near-ultraviolet spectrum of the object with the Space Telescope Imaging Spectrograph, and combine this with a new ground-based optical spectrum. The images confirm the gala

I. A. G. Snellen, M. D. Lehnert, M. N. Bremer, R. T. Schilizzi

This paper describes the selection of a new southern/equatorial sample of Gigahertz Peaked Spectrum (GPS) radio galaxies, and subsequent optical CCD imaging and spectroscopic observations using the ESO 3.6m telescope. The sample consists of 49 sources with -40<δ<+15 degrees, |b|>20 degrees, and S(2.7GHz)>0.5 Jy, selected from the Parkes PKSCAT90 survey. Abou

P. S. Ray, D. Chakrabarty

Observations of the 297 s X-ray pulsar 1E1145.1-6141 with the Rossi X-Ray Timing Explorer have revealed its 14.4 d eccentric orbit around its B supergiant companion. The best-fit orbital elements are: P_orb = 14.365(2) d, a_x sin i=99.4(18) light-s, e=0.20(3). No eclipses are detected, indicating that the binary inclination is less than 55 deg.

Monika Sinha, Jishnu Dey, Mira Dey, Subharthi Ray

A realistic equation of state (EOS) leads to realistic strange stars (ReSS) which are compact in the mass radius plot, close to the Schwarzchild limiting line (Dey et al 1998). Many of the observed stars fit in with this kind of compactness, irrespective of whether they are X-ray pulsars, bursters or soft $γ$ repeaters or even radio pulsars. We point out tha

Alfredo Gouveia Oliveira, Rodrigo de Abreu

Cosmic observations strongly support a time varying scenario for matter/space. On the other hand, so far, observations at solar system scale failed to identify any time variation on matter/space characteristics. To explain both results it is enough to consider a time variation of physical parameters liable to account for cosmic observations but satisfying Re

Brice Menard, Matthias Bartelmann, Yannick Mellier

Via the magnification bias, gravitational lensing by large-scale structures causes angular cross-correlations between distant quasars and foreground galaxies on angular scales of arc minutes and above. We investigate the three-point cross-correlation between quasars and galaxy pairs measurable via the second moment of the galaxy counts around quasars and sho

F. V. Prigara

In the gaseous disk model, the density profile is derived from the mass and energy conservation in the gravitational field of a central energy source. Using the condition for emission, following from the induced character of radiation process, we obtain the wavelength dependence of radio source size which is consistent with observational data.

Ivo Saviane, Alfred Rosenberg, Giampaolo Piotto, Antonio Aparicio

Using archival HST/WFPC2 imaging of 7 LMC globular clusters, and following the methods outlined in our previous study, we have reached the tightest constrain so far on their age dispersion, which cannot be greater than ~ 0.5 Gyr. We also confirm earlier results that their average age is comparable to that of the metal-poor Galactic globulars. Evidence is als

Guo-Xin Chen, Anil K. Pradhan, W. Eissner

A comprehensive study of relativistic and resonance effects in electron impact excitation of (e+Fe XVII) is carried out using the BPRM method in the relativistic close coupling approximation. Two sets of eigenfunction expansions are employed; first, up to the n = 3 complex corresponding 37 fine-structure levels (37CC) from 21 LS terms; second, up to the n =

Mauricio Bellini

I study ultralight particle creation which becomes from the Yukawa interaction between the inflaton and the thermal bath during fresh inflation. Particle creation is important in the first stages of fresh inflation, when the nonequilibrium thermal effects are important. I find that the number density of the ultralight created particles is more important as t

Paul Mansfield, David Nolland, Tatsuya Ueno

We compute the complete bulk one-loop contribution to the Weyl anomaly of the boundary theory for IIB Supergravity compactified on $ AdS_5\times S^5$. The result, that $δ{\cal A}=(E+I)/(2π^2)$, reproduces the subleading term in the exact expression ${\cal A}=-(N^2-1)(E+I)/(2π^2)$ for the Weyl anomaly of ${\cal N}=4$ Super-Yang-Mills theory, confirming the Ma

M. C. Bento, O. Bertolami, A. A. Sen

We consider cosmological inflation driven by the rolling tachyon in the context of the braneworld scenario. We show that sufficient inflation consistent with the observational constraints can be achieved for well defined upper limits on the five-dimensional mass scale, string mass scale and the string coupling for the bosonic string.

F. del Aguila, J. A. Aguilar-Saavedra

Top pair production at LHC is the ideal place to search for nonstandard Wtb couplings in t -> W b -> l nu b decays. The lb forward-backward asymmetry in the W rest frame is very sensitive to sigma_{mu nu} couplings, and can spot one-loop QCD corrections to the decay vertex with more than 5 sigma statistical significance. We discuss the potential of this asym

Akikazu Hashimoto, Savdeep Sethi

We study the dynamics of D-branes in a smooth time-dependent background. The theory on the branes is a time-dependent non-commutative field theory. We find the metric and fluxes that determine the dual holographic closed string theory. This provides a concrete example of holography in a cosmological setting.

P. G. Freeman, A. T. boothroyd, D. Prabhakaran, D. Gonzalez

The spin ordering of La3/2Sr1/2NiO4 was investigated by magnetization measurements, and by unpolarized- and polarized-neutron diffraction. Spin ordering with an incommensurability epsilon ~ 0.445 is observed below T_so ~ 80 K. On cooling, a spin reorientation is observed at 57 +/- 1 K, with the spin axes rotating from 52 +/- 4 degrees to 78 +/- 3 degrees. Th

Stephen L. Adler

We generalize the Weisskopf-Wigner theory for the line shape and transition rates of decaying states to the case of the energy-driven stochastic Schrödinger equation that has been used as a phenomenology for state vector reduction. Within the standard approximations used in the Weisskopf-Wigner analysis, and assuming that the perturbing potential inducing th

Mario Bonk, Bruce Kleiner

Suppose G is a Gromov hyperbolic group, and the boundary at infinity of G is quasisymmetrically homeomorphic to an Ahlfors Q-regular metric 2-sphere Z with Ahlfors regular conformal dimension Q. Then G acts discretely, cocompactly, and isometrically on hyperbolic 3-space.

Markus Lazar

A (linear) nonsingular solution for the edge dislocation in the translational gauge theory of defects is presented. The stress function method is used and a modified stress function is obtained. All field quantities are globally defined and the solution agrees with the classical solution for the edge dislocation in the far field. The components of the stress

Norio Konno, Takao Namiki, Takahiro Soshi, Aidan Sudbury

This paper treats absorption problems for the one-dimensional quantum walk determined by a 2 times 2 unitary matrix U on a state space {0,1,...,N} where N is finite or infinite by using a new path integral approach based on an orthonormal basis P, Q, R and S of the vector space of complex 2 times 2 matrices. Our method studied here is a natural extension of

Christof Wetterich

We compare different versions of a bosonic description for systems of interacting fermions, with particular emphasis on the free energy functional. The bosonic effective action makes the issue of symmetries particularly transparent and we present for the Hubbard model an exact mapping between repulsive and attractive interactions. A systematic expansion for

C. Wolf, K. Meisenheimer, H. -W. Rix, A. Borch

We present a detailed empirical assessment of how the galaxy luminosity function and stellar luminosity density evolves over the last half of the universe&#39;s age (0.2<z<1.2) for galaxies of different spectral energy distributions (SED). The results are based on ~25,000 galaxies (R<24) with redshift measurements (sigma_z~0.03) and SEDs across 350..930 nm,

M. Dietrich, F. Hamann, J. C. Shields, A. Constantin

We report on the analysis of a large sample of 744 type 1 Active Galactic Nuclei, including quasars and Seyfert 1 galaxies across the redshift range from 0 < z < 5 and spanning nearly 6 orders of magnitude in continuum luminosity. We discuss correlations of continuum and emission line properties in the rest-frame ultraviolet and optical spectral ranges. The

Srutarshi Pradhan, Bikas K. Chakrabarti

We consider first a homogeneous fiber bundle model where all the fibers have got the same stress threshold beyond which all fail simultaneously in absence of noise. At finite noise, the bundle acquires a fatigue behavior due to the noise-induced failure probability at any stress. We solve this dynamics of failure analytically and show that the average failur

A. G. J. van Leeuwen, B. W. Stappers, R. Ramachandran, J. M. Rankin

Both nulling and subpulse drifting are poorly understood phenomena. We probe their mechanisms by investigating how they interact in PSR B0809+74. We find that the subpulse drift is not aliased but directly reflects the actual motion of the subbeams. The carousel-rotation time must then be over 200 seconds, which is much longer than theoretically predicted. T

B. Basu-Mallick, Pijush K. Ghosh, Kumar S. Gupta

We show that the rational Calogero model with suitable boundary condition admits quantum states with non-equispaced energy levels. Such a spectrum generically consists of infinitely many positive energy states and a single negative energy state. The new states appear for arbitrary number of particles and for specific ranges of the coupling constant. These st

Michio Watanabe, Koji Ishibashi, Yoshinobu Aoyagi

We have studied the environmental effect on superconducting single-electron transistors (S-SETs) by biasing S-SETs with arrays of small-capacitance dc SQUIDs, whose effective impedance can be varied in situ. As the zero-bias resistance of the arrays is increased, Coulomb blockade in the S-SET becomes sharper, and the gate-voltage dependence changes from e-pe

L. Delle Site, C. F. Abrams, A. Alavi, K. Kremer

We study the properties of a polycarbonate melt near a nickel surface as a model system for the interaction of polymers with metal surfaces by employing a multiscale modeling approach. For bulk properties a suitably coarse grained bead spring model is simulated by molecular dynamics (MD) methods with model parameters directly derived from quantum chemical ca

K. Ghosh

In this article we discuss a few aspects of the space-time description of fields and particles. In sectionn II and III we demonstrate that fields are as fundamental as particles. In section IV we discuss non-equivalence of the Schwarzschild coordinates and the Kruskal-Szekeres coordinates. In section V we discuss that it is not possible to define causal stru

P. W. Lucas

A Monte Carlo light scattering code incorporating aligned non-spherical particles is described. The major effects on the flux distribution, linear polarisation and circular polarisation are presented, with emphasis on the application to Young Stellar Objects (YSOs). The need for models with non-spherical particles in order to successfully model polarisation

K. W. Becker, A. Huebsch, T. Sommer

This paper presents a renormalization approach to many-particle systems. By starting from a bare Hamiltonian ${\cal H}= {\cal H}_0 +{\cal H}_1$ with an unperturbed part ${\cal H}_0$ and a perturbation ${\cal H}_1$,we define an effective Hamiltonian which has a band-diagonal shape with respect to the eigenbasis of ${\cal H}_0$. This means that all transition

S. K. Moayedi, F. Darabi

We obtain classes of two dimensional static Lorentzian manifolds, which through the supersymmetric formalism of quantum mechanics admit the exact solvability of Dirac equation on these curved backgrounds. Specially in the case of a modified supersymmetric harmonic oscillator the wave function and energy spectrum of Dirac equation is given explicitly.

J. Kaneko, Belle Collaboration

We report the first measurement of the branching fraction for the inclusive decay B --> X(s) l+ l-, where l is either an electron or a muon and X(s) is a hadronic recoil system that contains an s-quark. We analyzed a data sample of 65.4 * 10**6 B meson pairs collected with the Belle detector at the KEKB e+e- asymmetric-energy collider. We find Br(B --> X(s)

Minoru Eto, Nobuhito Maru, Norisuke Sakai, Tsuyoshi Sakata

A BPS exact wall solution is found in N=1 supergravity in four dimensions. The model uses chiral scalar field with a periodic superpotential admitting winding numbers. Maintaining the periodicity in supergravity requires a gravitational correction to superpotential which allows the exact solution. By introducing boundary cosmological constants, we construct

Thomas Durt, Yves Pierseaux

Several no-go theorems showed the incompatibility between the locality assumption and quantum correlations obtained from maximally entangled spin states. We analyze these no-go theorems in the framework of Bohm&#39;s interpretation. The mechanism by which non-local correlations appear during the results of measurements performed on distant parts of entangled

Chiu Fan Lee, Neil F. Johnson

We consider how randomness can be made to play a useful role in quantum information processing - in particular, for decoherence control and the implementation of quantum algorithms. For a two-level system in which the decoherence channel is non-dissipative, we show that decoherence suppression is possible if memory is present in the channel. Random switching

M. Bache, Yu. B. Gaididei, P. L. Christiansen

A model is proposed where two $χ^{(2)}$ nonlinear waveguides are contained in a cavity suited for second-harmonic generation. The evanescent wave coupling between the waveguides is considered as weak, and the interplay between this coupling and the nonlinear interaction within the waveguides gives rise to quantum violations of the classical limit. These viol

Dmytro Babyuk

A behavior of quantum states (superposition of two lowest eigenstates, Gaussian wave packet) in phase space is studied for one and two dimensional double well potential. Two dimensional potential is constructed from double well potential coupled linearly and quadratically to harmonic potential. Quantum trajectories are compared with classical ones. Preferabl

T. J. Harmon, N. Moazzen-Ahmadi, R. I. Thompson

Sympathetic laser cooling of ions stored within a linear-geometry, radio frequency, electric-quadrupole trap has been investigated using computational and theoretical techniques. The simulation, which allows 5 sample ions to interact with 35 laser-cooled atomic ions, revealed an instability heating mechanism, which can prevent ions below a certain critical m

D. H. E. Gross

The recent paper nucl-th/0208024 by Moretto et al. is commented: Their picture of nuclear phase transition in terms of macroscopic control parameters, temperature and pressure, is irrelevant. Their criticism of order-disorder phase-transitions on a periodic lattice uses the wrong scenario. This transition has nothing to do with the liquid-gas transition of a

B. Juliá-Díaz, A. Valcarce, P. González, F. Fernández

A $NN\to NN^{\ast}(1440)$ transition potential, based on an effective quark-quark interaction and a constituent quark cluster model for baryons, is derived in the Born-Oppenheimer approach. The potential shows significant differences with respect to those obtained by a direct scaling of the nucleon-nucleon interaction. From its asymptotic behavior we extract

K. Hagino, A. B. Balantekin

We discuss the effect of electromagnetic environment on laboratory measurements of the nuclear fusion reactions of astrophysical interest. The radiation field is eliminated using the path integral formalism in order to obtain the influence functional, which we evaluate in the semi-classical approximation. We show that enhancement of the tunneling probability

A. M. Kamchatnov, M. V. Pavlov

It is shown that the self-induced transparency equations can be interpreted as a generating function for as positive so negative flows in the AKNS hierarchy. Mutual commutativity of these flows leads to other hierarchies of integrable equations. In particular, it is shown that stimulated Raman scattering equations generate the hierarchy of flows which includ

J. Plebanski, M. Przanowski, F. J. Turrubiates

Weyl-Underhill-Emmrich (WUE) quantization and its generalization are considered. It is shown that an axiomatic definition of the Stratonovich-Weyl (SW) quantizer leads to severe difficulties. Quantization on the cylinder within the WUE formalism is discussed.

David Damanik, Luca Q. Zamboni

We consider Arnoux-Rauzy subshifts $X$ and study various combinatorial questions: When is $X$ linearly recurrent? What is the maximal power occurring in $X$? What is the number of palindromes of a given length occurring in $X$? We present applications of our combinatorial results to the spectral theory of discrete one-dimensional Schrödinger operators with p

Alexander Tumanov

We prove the following result. Let f be a continuous function in the closed infinite strip in complex plane. Suppose the restriction of f to every circle inscribed in the strip extends holomorphically inside the circle. Then f is holomorphic in the open strip.

Martin Goldstern

A semiring can be ``completed&#39;&#39; (i.e., embedded into a semiring in which all infinite sums are defined and satisfy some reasonable properties) iff this semiring can be naturally partially ordered. This construction is ``natural&#39;&#39; (a left adjoint to the forgetful functor), and quite straightforward.

Tobias H. Colding, Nancy Hingston

We give in this paper bounds for the Morse indices of a large class of simple geodesics on a surface with a generic metric. To our knowledge these bounds are the first that use only the generic hypothesis on the metric.

W. P. de Souza

The Thermo Field Dynamics formalism is presented. In particular, it is applied to the two-dimensional field theory that describes a open bosonic string. The value of entropy operator is computed in various Dirichlet and Neumann boundary states. The Thermal Bogoliubov transformations, the thermal vacuum and the thermal Fock space are computed explicitely for

A. E. Shabad

We consider the radial Schroedinger equation with an attractive potential singular in the origin. The additional continuum of states caused by the singularity, that usually remain nontreatable, are shown to correspond to particles, asymptotically free near the singularity (in the inner channel). Depending on kinematics, they are either confined by the centre

Christian Brouder

If C is a cocommutative coalgebra, a bialgebra structure can be given to the symmetric algebra S(C). The symmetric product is twisted by a Laplace pairing and the twisted product of any number of elements of S(C) is calculated explicitly. This is used to recover important identities in the quantum field theory of interacting scalar bosons.

Peter Gilkey, Klaus Kirsten, Dmitri Vassilevich

We compute the first 5 terms in the short-time heat trace asymptotics expansion for an operator of Laplace type with transfer boundary conditions using the functorial properties of these invariants.

A. V. Yurov

We investigate cosmology with complex scalar field. It is shown that such models can describe two stages of inflation and the oscillatory regime. Thus we don&#39;t need both quintessence and $Λ$-term. It is enough to have single complex field to obtain both inflation and present accelerated universe. If the present accelerated expansion was created by the co

B. Ram

A quantum theory of the region of pure gravitation was given earlier in two papers [gr-qc/9908036 (Phys. Lett. A {\bf {265}}, 1 (2000)); gr-qc/0101056]. In this paper I provide further insight into the physics of this region.

V. Schatz

Different models for the odderon-proton coupling are considered and their effects on the differential cross section in the dip region in elastic p p and p pbar scattering are investigated. An allowed range for the size of a possible diquark cluster in the proton can be obtained from a geometrical model.

Michail P. Rekalo, Egle Tomasi-Gustafsson

We suggest a method to determine the product of the coupling constants $g_{ρσγ}g_ {σNN}$, in absolute value and relative sign, through the $t$-dependence of the two possible T-even asymmetries for the photoproduction of vector mesons, $γ+p\to p+V^0$, $V^0=ρ$ or $ω$, in the collision of circularly polarized photons with a polarized proton target. In the frame

J. P. Lansberg, F. Bissey, J. R. Cudell, J. Cugnon

The pion structure function is investigated in a simple model, where the pion and its constituent quark fields are coupled through the simplest pseudoscalar coupling. The imaginary part of the forward gamma* pi -> gamma* pi scattering amplitude is evaluated and related to the structure functions. It is shown that the introduction of non-perturbative effects,

V. A. Bednyakov

The neutralino relic density is calculated in the low-energy effective Minimal Supersymmetric extension of Standard Model (effMSSM). The slepton-neutralino, squark-neutralino and neutralino/chargino-neutralino coannihilation channels are taking into account. The comparative study of these coannihilations is performed and demonstrated that all of them give th

Masud Chaichian, Archil Kobakhidze

We discuss Kaluza-Klein (KK) decomposition in 5-dimensional (5D) field theories with orbifold compactification. Kinetic terms localized at orbifold fixed points, which are inevitably present in any realistic model, modify the standard KK mass spectrum and interactions of KK modes. This, in turn, can significantly affect phenomenology of the orbifold models.

I. Wetzorke, F. Karsch

We present our final results for the mass of the six quark flavor singlet state (J^P=0^+, S=-2) called H dibaryon, which would be the lightest possible strangelet in the context of strange quark matter. The calculations are performed in quenched QCD on (8-24)^3 x 30 lattices with the (1,2) Symanzik improved gauge action and the clover fermion action. Further

M. N. Chernodub, E. -M. Ilgenfritz, A. Schiller

We study the lattice gauge boson propagator of 3D compact QED in Landau gauge at zero and non-zero temperature. Non-perturbative effects are reflected by the generation of a mass $m$, by an anomalous dimension $α$ and by the photon wave function renormalisation $Z$. These effects can be attributed to monopoles: they are absent in the propagator of the regula

C. R. Allton, J. E. Clowser, S. J. Hands, J. B. Kogut

We investigate spectral functions extracted using the Maximum Entropy Method from correlators measured in lattice simulations of the (2+1)-dimensional four-fermion model. This model is particularly interesting because it has both a chirally broken phase with a rich spectrum of mesonic bound states and a symmetric phase where there are only resonances. In the

A. Galoyan, E. N. Kladnitskaya, O. V. Rogachevskii, R. Togoo

Experimental data on multiplicities and kinematical characteristics of $π^-$, $π^+$ mesons and protons in the interactions of protons with carbon nucleus at momentum 4.2 GeV/c in a dependence of collision centrality are analyzed. Parameter Q which is a difference between multiplicities of positive and negative charged particles without multiplicity of slow p

Guenter Grindhammer

Dijet production in deep-inelastic scattering (DIS) in the range 150 < Q^2 < 35000 GeV^2 has been measured by the H1 collaboration using the Durham jet algorithm in the laboratory frame. QCD calculations in next-to-leading order (NLO) are found to give a good description of the data when requiring a small minimum jet separation, which selects a dijet sample

The Belle Collaboration, K. Abe

We report on a study of charmless B meson decays to three-kaon final states. The results are obtained with a 78.7 1/fb data sample collected on the Y(4S) resonance by the Belle detector operating at the KEKB asymmetric energy $e^+e^-$ collider. The branching fractions for B decays to three-body K+K+K-, K0K+K-, KsKsK+, and KsKsKs final states are presented. W