July 2002 arXiv papers — page 2

Q. C. Qiu, J. L. Dunn, C. A. Bates, M. Abou-Ghantous

Reduction factors (RF), that are needed when modeling vibronic systems by an effective Hamiltonian in an electronic basis, are calculated for the T_1u x h_g Jahn-Teller (JT) system. The results obtained will be useful when modeling the fullerene anion C_60-, which is believed to exhibit a T_1u x h_g JT effect in its ground state. First-order RF's are cal

S. Krompiewski

Effect of contact interfaces, between metallic single-wall carbon nanotubes (SWCNT) and external electrodes made also of nanotubes, on the electrical conductance is studied. A tight-binding model with both diagonal and off-diagonal disorder, a recursive Green function technique as well as the Landauer formalism are used. The studies are carried out within th

Marco Cecchini, Vincenzo Piazza, Fabio Beltram, Marco Lazzarino

Planar light-emitting diodes (LEDs) fabricated within a single high-mobility quantum well are demonstrated. Our approach leads to a dramatic reduction of radiative lifetime and junction area with respect to conventional vertical LEDs, promising very high-frequency device operation. Devices were fabricated by UV lithography and wet chemical etching starting f

R. Oppermann, D. Sherrington

Models with range-free frustrated Ising spin- and Hubbard interaction are treated exactly by means of the discrete time slicing method. Critical and tricritical points, correlations, and the fermion propagator, are derived as a function of temperature T, chemical potential μ, Hubbard coupling U, and spin glass energy J. The phase diagram is obtained. Replica

Mathieu Taillefumier, Delphine Cabaret, Anne-Marie Flank, Francesco Mauri

We present a reciprocal-space pseudopotential scheme for calculating X-ray absorption near-edge structure (XANES) spectra. The scheme incorporates a recursive method to compute absorption cross section as a continued fraction. The continued fraction formulation of absorption is advantageous in that it permits the treatment of core-hole interaction through la

H. W. Schumacher, C. Chappert, R. C. Sousa, P. P. Freitas

We demonstrate a quasi ballistic switching of the magnetization in a microscopic mag-neto resistive memory cell. By means of time resolved magneto transport we follow the large angle precession of the free layer magnetization of a spin valve cell upon applica-tion of transverse magnetic field pulses. Stopping the field pulse after a 180 degree precession rot

P. Tegzes, T. Vicsek, P. Schiffer

A detailed characterization of avalanche dynamics of wet granular media in a rotating drum apparatus is presented. The results confirm the existence of the three wetness regimes observed previously: the granular, the correlated and the viscoplastic regime. These regimes show qualitatively different dynamic behaviors which are reflected in all the investigate

J. Klein, J. B. Philipp, G. Carbone, A. Vigliante

Due to the complex interplay of magnetic, structural, electronic, and orbital degrees of freedom, biaxial strain is known to play an essential role in the doped manganites. For coherently strained La(2/3)Ca(1/3)MnO(3) thin films grown on SrTiO(3) substrates, we measured the magnetotransport properties both parallel and perpendicular to the substrate and foun

Robin Stinchcombe, Martin Depken

A diffusion-deposition model for glassy dynamics in compacting granular systems is treated by time scaling and by a method that provides the exact asymptotic (long time) behavior. The results include Vogel-Fulcher dependence of rates on density, inverse logarithmic time decay of densities, exponential distribution of decay times and broadening of noise spect

P. S. Mohanty, B. V. R. Tata

Monte Carlo simulations have been performed for aqueous charged colloidal suspensions as a function of charge density on the particles and salt concentration. We vary the charge density in our simulations over a range where a reentrant solid-liquid transition in suspensions of silica and polymer latex particles has been reported by Yamanaka et al. [Phys. Rev

J. Horvat, S. Soltanian, X. L. Wang, S. X. Dou

Transport critical current (Ic) was measured for MgB2/Fe round wires, with magnetic field oriented perpendicular to the wire and parallel to it. Measurements were made on a wire with pure MgB2 core and another wire where MgB2 core was doped with nano-size SiC. This doping strongly improved the vortex pinning in MgB2. The field dependence of Ic was strongly i

P. K. Mishra, S. Kumar, Y. Singh

We use the lattice model of directed walks to investigate the conformational as well as the adsorption properties of a semiflexible homopolymer chain immersed in a good solvent in two and three dimensions. To account for the stiffness in the chain we have introduced energy barrier for each bend in the walk and have calculated the persistent length as a funct

John Evans, Fredrick Michael

In this article the statistical properties of symmetrical random matrices whose elements are drawn from a q-parametrized non-extensive statistics power-law distribution are investigated. In the limit as q->1 the well known Gaussian orthogonal ensemble (GOE) results are recovered. The relevant level spacing distribution is derived and one obtains a suitably g

Marcio Argollo de Menezes, Ronald Dickman

In cond-mat/0107371, Mendonca proposes that diffusion can change the universality class of a parity-conserving reaction-diffusion process. In this comment we suggest that this cannot happen, due to symmetry arguments. We also present numerical results from lattice simulations which support these arguments, and mention a previous result supporting this conclu

Paul Martini, Daniel D. Kelson, John S. Mulchaey, Scott C. Trager

As part of a program to study the evolution of active galactic nuclei (AGN) in clusters of galaxies, we present our results for Abell 2104. A deep Chandra observation of this massive, z = 0.154 cluster reveals a significant X-ray point source excess over the expectations of blank fields, including eight X-ray counterparts with R<20 mag. Our spectroscopy show

M. Mouhcine

In this paper,we present single stellar population models of intermediate age stellar populations where dust-enshrouded AGB stars are introduced. The formation of carbon stars is also accounted for, and is taken to be a function of both initial mass and metallicity. The effect of the dusty envelopes around AGB stars on the optical/near-infrared spectral ener

H. C. Harris, C. C. Dahn, F. J. Vrba, H. H. Guetter

Trigonometric parallaxes have been measured by Dahn et al. (2002) for 28 cool dwarfs and brown dwarfs, including 17 L dwarfs and three T dwarfs. Broadband CCD and near-IR photometry (VRIz*JHK) have been obtained for these objects and for 24 additional late-type dwarfs. These data have been supplemented with astrometry and photometry from the literature, incl

Jeonghee Rho, Kristy K. Dyer, Kazimierz J. Borkowski, Stephen P. Reynolds

Supernova remnants may exhibit both thermal and nonthermal X-ray emission. We present Chandra observations of RCW 86. Striking differences in the morphology of X-rays below 1 keV and above 2 keV point to a different physical origin. Hard X-ray emission is correlated fairly well with the edges of regions of radio emission, suggesting that these are the locati

Knox S. Long, Christian Knigge

Bipolar outflows are present in many disk-accreting astrophysical systems. In disk-accreting cataclysmic variables (CVs), these outflows are responsible for most of the strong features in the ultraviolet spectra of these systems. However, there have been few attempts to model these features quantitatively. Here, we describe a new, hybrid Monte Carlo/Sobolev

Craig J. Copi, Lawrence M. Krauss

We compare the sensitivity of WIMP detection via direct separation of possible signal vs. background to WIMP detection via detection of an annual modulation, in which signal and background cannot be separated on an event-by-event basis. In order to determine how the constraints from the two different types of experiments might be combined an adequate incorpo

B. P. Wakker, B. D. Savage, K. R. Sembach, P. Richter

We present FUSE observations of OVI absorption in a sample of 100 extragalactic targets and 2 distant halo stars. We describe the details of the calibration, alignment in velocity, continuum fitting, and manner in which contaminants were removed (Galactic H2, absorption intrinsic to the background target and intergalactic Ly-beta lines). We searched for OVI

J. Ahrens, X. Bai, G. Barouch, S. W. Barwick

This paper describes the search for astronomical sources of high-energy neutrinos using the AMANDA-B10 detector, an array of 302 photomultiplier tubes, used for the detection of Cherenkov light from upward traveling neutrino-induced muons, buried deep in ice at the South Pole. The absolute pointing accuracy and angular resolution were studied by using coinci

Yen-Ting Lin, Joseph J. Mohr

We explore the cosmological implications of 7 deep survey fields observed at the Berkeley-Illinois-Maryland Association (BIMA) Array with 30 GHz receivers. These observations probe the Cosmic Microwave Background anisotropy on scales corresponding to l=5500, and an earlier analysis of these data detected no galaxy clusters. We use numerical cluster simulatio

Andrew Gould

Using a reduced proper motion discriminator, I obtain a sample of 4588 subdwarfs from the Revised NLTT Catalog of Salim & Gould. The ample statistics and low contamination permit much more precise determinations of halo parameters than has previously been possible. The stellar halo is not moving with respect to the Local Standard of Rest (LSR) in either the

Edward A. Baltz, P. Gondolo

The new measurement of the anomalous magnetic moment of the muon by the Brookhaven AGS experiment 821 again shows a discrepancy with the Standard Model value. We investigate the consequences of these new data for neutralino dark matter, updating and extending our previous work [E. A. Baltz and P. Gondolo, Phys. Rev. Lett. 86, 5004 (2001)]. The measurement ex

J. Davy Kirkpatrick

Studies of brown dwarfs as a distinct galactic population have been largely pioneered by dedicated, vast-area surveys at deep optical and near-infrared wavebands. The Two Micron All Sky Survey has, because of its full-sky coverage and depth, been the most successful at providing new targets for further study. The author briefly reviews some of the ways in wh

Gianfranco Brunetti

In the framework of the study of extragalactic radio sources, we will focus on the importance of the spatial resolution at different wavelengths, and of the combination of observations at different frequency bands. In particular, a substantial step forward in this field is now provided by the new generation X-ray telescopes which are able to image radio sour

E. Aprile, E. A. Baltz, A. Curioni, K-L. Giboni

XENON is a novel liquid xenon experiment concept for a sensitive dark matter search using a 1-tonne active target, distributed in an array of ten independent time projection chambers. The design relies on the simultaneous detection of ionization and scintillation signals in liquid xenon, with the goal of extracting as much information as possible on an event

Dayton L. Jones, Ann E. Wehrle

We have used the VLBA to produce a high dynamic range image of the nucleus of NGC 6251 at 1.6 GHz and snapshot images at 5.0, 8.4, and 15.3 GHz to search for emission from a parsec-scale counterjet. Previous VLBI images at 1.6 GHz have set a lower limit for the jet/counterjet brightness ratio near the core at about 80:1, which is larger than expected given t

P. Bergeron, S. K. Leggett

A detailed analysis of the very cool white dwarfs SDSS 1337+00 and LHS 3250 is presented. Model atmosphere calculations with improved collision-induced absorptions by molecular hydrogen indicate that a pure hydrogen composition can be ruled out, and that the strong infrared absorption observed in these cool stars is better explained in terms of collisions of

V. E. Barnard, A. W. Blain, N. R. Tanvir, P. Natarajan

We present the results of a search for submillimetre-luminous host galaxies of optically dark gamma-ray bursts (GRBs) using the Submillimetre Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT). We made photometry measurements of the 850-micron flux at the location of four `dark bursts&#39;, which are those with no detected optica

P. V. Tytarenko, R. J. R. Williams, S. A. E. G. Falle

We analyse the stability of a magnetized medium consisting of a neutral fluid and a fluid of charged particles, coupled to each other through a drag force and exposed to differential body forces (for example, as the result of radiation forces on one phase). We consider a uniform equilibrium and simple model input physics, but do not arbitrarily restrict the

I. Waddington, R. A. Windhorst, S. H. Cohen, J. S. Dunlop

Deep spectroscopy of the two mJy radio galaxies LBDS 53W069 and 53W091 has previously shown them to have old (>3 Gyr) stellar populations at z=1.5. Here we present the results of HST observations of these galaxies. 53W069 has an r^1/4 profile in both the F814W & F110W data with an effective radius of 0.30 arcsec (2.7 kpc). The restframe U-B colour gradient r

Neal A. Miller, Frazer N. Owen

(Abridged) We have used optical spectroscopy to investigate the radio- selected active galaxy populations in a sample of 20 nearby Abell clusters. The spectra were used to characterize the galaxies as AGN or galaxies forming stars at rates comparable to or greater than the Milky Way. A significant population of star forming galaxies with large amounts of nuc

Varsha P. Kulkarni, S. Michael Fall

We have reanalyzed the existing data on Zinc abundances in damped Ly-alpha (DLA) absorbers to investigate whether their mean metallicity evolves with time. Most models of cosmic chemical evolution predict that the mass- weighted mean interstellar metallicity of galaxies should rise with time from a low value ~ 1/30 solar at z ~ 3 to a nearly solar value at z

Jorge Melendez, Beatriz Barbuy

Infrared OH lines at 1.5 - 1.7 um in the H band were obtained with the NIRSPEC high-resolution spectrograph at the 10m Keck Telescope for a sample of seven metal-poor stars. Detailed analyses have been carried out, based on optical high-resolution data obtained with the FEROS spectrograph at ESO. Stellar parameters were derived by adopting infrared flux meth

T. Bulik, K. Belczynski, V. Kalogera

Using the StarTrack population synthesis code we compute the distribution of masses of merging compact object (black hole or neutron star) binaries. The shape of the mass distribution is sensitive to some of the parameters governing the stellar binary evolution. We discuss the possibility of constraining stellar evolution models using mass measurements obtai

M. S. Marley, A. Ackerman, A. J. Burgasser, D. Saumon

A sophisticated approach to condensate opacity is required to properly model the atmospheres of L and T dwarfs. Here we review different models for the treatment of condensates in brown dwarf atmospheres. We conclude that models which include both particle sedimentation and upwards transport of condensate (both gas and particles) provide the best fit for the

Andres Jordan, Patrick Cote, Michael J. West, R. O. Marzke

Relative ages for the globular cluster (GC) subpopulations in the Virgo giant elliptical galaxy M87 (NGC 4486) have been determined from Stroemgren photometry obtained with WFPC2 on board HST. Using a variety of population synthesis models, and assuming the GC mass at the turnover of the luminosity function is the same for both subpopulations, differential a

J. Davy Kirkpatrick

The Next Generation Sky Survey (NGSS) is a proposed NASA MIDEX mission to map the entire sky in four infrared bandpasses - 3.5, 4.7, 12, and 23 um. The seven-month mission will use a 50-cm telescope and four-channel imager to survey the sky from a circular orbit above the Earth. Expected sensitivities will be half a million times that of COBE/DIRBE at 3.5 an

Michal Horodecki, Jonathan Oppenheim, Ryszard Horodecki

We argue that on its face, entanglement theory satisfies laws equivalent to thermodynamics if the theory can be made reversible by adding certain bound entangled states as a free resource during entanglement manipulation. Subject to plausible assumptions, we prove that this is not the case in general, and discuss the implications of this for the thermodynami

Marco Chiaberge, Alessandro Capetti, Annalisa Celotti

We extend our study of the nuclei of 3CR FR II radio galaxies through HST optical images up to z=0.3. In the majority of them an unresolved nucleus (central compact core, CCC) is found. We analyze their position in the plane formed by the radio and optical nuclear luminosities in relation to their optical spectral properties. The broad-lined objects (BLO) ha

C. Mudry, S. Ryu, A. Furusaki

Gade [R. Gade, Nucl. Phys. B \textbf{398}, 499 (1993)] has shown that the local density of states for a particle hopping on a two-dimensional bipartite lattice in the presence of weak disorder and in the absence of time-reversal symmetry(chiral unitary universality class) is anomalous in the vicinity of the band center $ε=0$ whenever the disorder preserves t

Jerome Levine

In a previous paper [Homology cylinders: an enlargement of the mapping class group, Algebr. Geom. Topol. 1 (2001) 243--270, arXiv:math.GT/0010247], a group H_g of homology cylinders over the oriented surface of genus g is defined. A filtration of H_g is defined, using the Goussarov-Habiro notion of finite-type. It is erroneously claimed that this filtration

N. E. Mavromatos, R. J. Szabo

We describe the general features of the Neveu-Schwarz and Ramond sectors of logarithmic conformal field theories with N=1 supersymmetry. Three particular systems are examined in some detail -- D-brane recoil, a superconformal extension of the c=-2 model, and the supersymmetric SU(2)_2 WZW model.

Jeppe C. Dyre

It is suggested that the spectrum of ion site energies in glasses exhibits a band gap, establishing an analogy between ion conducting glasses and intrinsic semiconductors. This implies that ion conduction in glasses takes place via vacancies and interstitial ions (as in crystals).

Gudrun Hiller

We comment on the implications of the recently measured CP asymmetry in B --> Phi K_S decay. The data disfavor the Standard Model at 2.7 sigma and -if the trend persists in the future with higher statistics - require the existence of CP violation beyond that in the CKM matrix. In particular, the b --> s bar{s} s decay amplitude would require new contribution

Hideki Maeda, Tomohiro Harada, Hideo Iguchi, Naoya Okuyama

We classify all spherically symmetric spacetimes admitting a kinematic self-similar vector of the second, zeroth or infinite kind. We assume that the perfect fluid obeys either a polytropic equation of state or an equation of state of the form $p=Kμ$, where $p$ and $μ$ are the pressure and the energy density, respectively, and $K$ is a constant. We study the

Kevin Iga

In 1983, Donaldson shocked the topology world by using instantons from physics to prove new theorems about four-dimensional manifolds, and he developed new topological invariants. In 1988, Witten showed how these invariants could be obtained by correlation functions for a twisted N=2 SUSY gauge theory. In 1994, Seiberg and Witten discovered dualities for suc

Gary T. Horowitz, Kengo Maeda

We construct an exact solution describing the collision of two Kaluza-Klein &#34;bubbles of nothing&#34; in 3+1 dimensions. When the bubbles collide, a curvature singularity forms which is hidden inside an event horizon. However, unlike the formation of ordinary black holes, in this case the spacetime resembles the entire maximally extended Schwarzschild sol

M. A. Cazalilla

We study the surface modes of some of the vortex liquids recently found by means of exact diagonalizations in systems of rapidly rotating bosons. In contrast to the surface modes of Bose condensates, we find that the surface waves have a frequency linear in the excitation angular momentum, $\hbar l > 0$. Furthermore, in analogy with the edge waves of electro

Eduardo Cattani, Javier Fernandez

We exhibit a direct correspondence between the potential defining the H^{1,1} small quantum module structure on the cohomology of a Calabi-Yau manifold and the asymptotic data of the A-model variation of Hodge structure. This is done in the abstract context of polarized variations of Hodge structure and Frobenius modules.

Silvia De Monte, Francesco d&#39;Ovidio, Erik Mosekilde

The paper presents a method by which the mean field dynamics of a population of dynamical systems with parameter diversity and global coupling can be described in terms of a few macroscopic degrees of freedom. The method applies to populations of any size and functional form in the region of coherence. It requires linear variation or a narrow distribution fo

F. Faure, S. Nonnenmacher, S. De Bievre

In this paper we construct a sequence of eigenfunctions of the ``quantum Arnold&#39;s cat map&#39;&#39; that, in the semiclassical limit, show a strong scarring phenomenon on the periodic orbits of the dynamics. More precisely, those states have a semiclassical limit measure that is the sum of 1/2 the normalized Lebesgue measure on the torus plus 1/2 the nor

Ernest Ma

A four-parameter Majorana neutrino mass matrix is proposed, which is exactly diagonalizable with two mixing angles, one of which is pi/4 and the other large but less than pi/4. The form of this mass matrix allows seven realizations of the present data on atmospheric and solar neutrino oscillations: three have the normal hierarchy, two have the inverse hierar

J. R. Espinosa, Y. Yamada

The existing definitions of mixing angles (one-loop radiatively corrected and renormalization-scale-independent) for scalar particles turn out to be gauge-dependent when used in gauge theories. We show that a scale- and gauge-independent mixing angle can be obtained if the scalar self-energy is improved by the pinch technique, and give two relevant examples

Jose A. Oller

We have established a new convergent scheme to treat analytically nucleon-nucleon interactions from a chiral effective field theory. The Kaplan-Savage-Wise (KSW) amplitudes are resummed to fulfill the unitarity or right hand cut to all orders below pion production threshold. This is achieved by matching order by order in the KSW power counting the general ex

Nadav Drukker

Closed string diagrams are derived from cubic open string field theory using a gauge fixed kinetic operator. The basic idea is to use a string propagator that does not generate a boundary to the world sheet. Using this propagator and the closed string vertex, the moduli space of closed string surfaces is covered, so closed string scattering amplitudes should

M. Cvitan, S. Pallua, P. Prester

We treat spherically symmetric black holes in Gauss-Bonnet gravity by imposing boundary conditions on fluctuating metric on the horizon. Obtained effective two-dimensional theory admits Virasoro algebra near the horizon. This enables, with the help of Cardy formula, evaluation of the number of states. Obtained results coincide with the known macroscopic expr

I. B. Khriplovich, G. G. Kirilin

We have found the graviton contribution to the one-loop quantum correction to the Newton law. This correction results in interaction decreasing with distance as 1/r^3 and is dominated numerically by the graviton contribution. The previous calculations of this contribution to the discussed effect are demonstrated to be incorrect.

Nakwoo Kim, Kimyeong M. Lee, Piljin Yi

M(atrix) theory is known to be mass-deformed in the pp-wave background and still retains all 16 dynamical supersymmetries. We consider generalization of such deformations on super Yang-Mills quantum mechanics (SYQM) with less supersymmetry. In particular this includes N=8 U(N) SYQM with a single adjoint and any number of fundamental hypermultiplets, which is

T. Multamaki, I. Vilja

We consider six dimensional brane world models with a compact and a warped extra dimension with five dimensional branes. We find that such scenarios have many interesting features arising from both ADD and Randall-Sundrum -models. In particular we study a class of models with a single 5D brane and a finite warped extra dimension, where one of the brane dimen

Hidetoshi Nishimori, Cyril Falvo, Yukiyasu Ozeki

We study the two-dimensional +/-J Ising model, three-state Potts model and four-state Potts model, by the numerical transfer matrix method to investigate the behaviour of the sample-to-sample fluctuations of the internal energy on the Nishimori line. The result shows a maximum at the multicritical point in all the models we investigated. The large sample-to-

Wen-Fa Lu, Chul Koo Kim, Kyun Nahm

Combining an optimized expansion scheme in the spirit of the background field method with the Coleman&#39;s normal-ordering renormalization prescription, we calculate the effective potential of sine-Gordon field theory beyond the Gaussian approximation. The first-order result is just the sine-Gordon Gaussian effective potential (GEP). For the range of the co

Kin Wong, Sascha Vongehr, Vitaly V. Kresin

We revisit a model in which the ionization energy of a metal particle is associated with the work done by the image charge force in moving the electron from infinity to a small cut-off distance just outside the surface. We show that this model can be compactly, and productively, employed to study the size dependence of electron removal energies over the rang

Jihn E. Kim, Hyun Min Lee

We find more self-tuning solutions by introducing a general form for Lagrangian of a 3-index antisymmetric tensor field $A_{MNP}$ in the RS II model. In particular, for the logarithmic Lagrangian, $\propto\log(-H^2)$, we obtained a closed form weak self-tuning solution.

Zhi-De Chen, J. -Q. Liang, Shun-Qing Shen

Renormalized tunnel splitting with a finite distribution in the biaxial spin model for molecular magnets is obtained by taking into account the dipolar interaction of enviromental spins. Oscillation of the resonant tunnel splitting with a transverse magnetic field along the hard axis is smeared by the finite distribution which subsequently affects the quantu

M. A. Batanin

The classical Eckmann-Hilton argument shows that two monoid structures on a set, such that one is a homomorphism for the other, coincide and, moreover, the resulting monoid is commutative. This argument immediately gives a proof of the commutativity of the higher homotopy groups. A reformulation of this argument in the language of higher categories is: suppo

R. Fedele, M. A. Man&#39;ko, V. I. Man&#39;ko, V. G. Vaccaro

It is shown that the transmission line technology can be suitably used for simulating quantum mechanics. Using manageable and at the same time non-expensive technology, several quantum mechanical problems can be simulated for significant tutorial purposes. The electric signal envelope propagation through the line is governed by a Schrodinger-like equation fo

John Jeffers, Stephen M. Barnett, David T. Pegg

In the Jaynes-Cummings model a two-level atom interacts with a single-mode electromagnetic field. Quantum mechanics predicts collapses and revivals in the probability that a measurement will show the atom to be excited at various times after the initial preparation of the atom and field. In retrodictive quantum mechanics we seek the probability that the atom

David T. Pegg, Stephen M. Barnett, John Jeffers

The conventional postulate for the probabilistic interpretation of quantum mechanics is asymmetric in preparation and measurement, making retrodiction reliant on inference by use of Bayes&#39; theorem. Here, a more fundamental symmetric postulate is presented, from which both predictive and retrodictive probabilities emerge immediately, even where measuremen

A. Iorio, G. Lambiase, G. Vitiello

A suitable deformation of the Hopf algebra of the creation and annihilation operators for a complex scalar field, initially quantized in Minkowski space--time, induces the canonical quantization of the same field in a generic gravitational background. The deformation parameter q turns out to be related to the gravitational field. The entanglement of the quan

R. Laflamme, E. Knill, D. G. Cory, E. M. Fortunato

After a general introduction to nuclear magnetic resonance (NMR), we give the basics of implementing quantum algorithms. We describe how qubits are realized and controlled with RF pulses, their internal interactions, and gradient fields. A peculiarity of NMR is that the internal interactions (given by the internal Hamiltonian) are always on. We discuss how t

E. Knill, R. Laflamme, H. Barnum, D. Dalvit

As a result of the capabilities of quantum information, the science of quantum information processing is now a prospering, interdisciplinary field focused on better understanding the possibilities and limitations of the underlying theory, on developing new applications of quantum information and on physically realizing controllable quantum devices. The purpo

E. Knill, R. Laflamme, A. Ashikhmin, H. Barnum

In this introduction we motivate and explain the ``decoding&#39;&#39; and ``subsystems&#39;&#39; view of quantum error correction. We explain how quantum noise in QIP can be described and classified, and summarize the requirements that need to be satisfied for fault tolerance. Considering the capabilities of currently available quantum technology, the requir

Scott Aaronson

This is a critical review of the book &#39;A New Kind of Science&#39; by Stephen Wolfram. We do not attempt a chapter-by-chapter evaluation, but instead focus on two areas: computational complexity and fundamental physics. In complexity, we address some of the questions Wolfram raises using standard techniques in theoretical computer science. In physics, we

Jaroslaw Zalesny

The origin of the Kerr type nonlinearity of the medium as a result of the interaction between photons via the Dirac delta-potential is presented in the formalism adopted from the photon wave function approach. In the view of the result the optical soliton may be treated as a bound state (cluster) of many photons.

J. Roques, F. Calvo, F. Spiegelman, C. Mijoule

Based on ab initi and density-functional theory calculations, an empirical potential is proposed to model the interaction between a fullerene molecule and many sodium atoms. This model predicts homogeneous coverage of C_60 below 8 Na atoms, and a progressive droplet formation above this size. The effects of ionization, temperature, and external electric fiel

M. T. Meftah, Is. Chihi, F. Khelfaoui, H. Bouguettaia

In this paper the results of Lyman alpha line shapes without the fine structure in the electron impact approximation are rederived using a path integral formalism. The method presented here is designed to provide a quantum formalism that will treat the ions and the electrons on the same physical basis. This method has also the advantage of treating cases whe

V. Granik, A. Granik

Proceeding from the concept of rational expectations, a new dynamic model of supply and demand in a single market with one supplier, one buyer, and one kind of commodity is developed. Unlike the cob-web dynamic theories with adaptive expectations that are made up of deterministic difference equations, the new model is cast in the form of stochastic different

C. Broadbent, G. Hovhannisyan, J. Peatross, M. Clayton

We introduce notions of free energy and loss in linear, absorbing dielectric media which are relevant to the regime in which the macroscopic Maxwell equations are themselves relevant. As such we solve a problem eluded to by Landau and Lifshitz in 1958, and later considered explicitly by Barash and Ginzburg, and Oughtsun and Sherman. As such we provide physic

Rajendran Raja

Maximum likelihood fits to data can be done using binned data (histograms) and unbinned data. With binned data, one gets not only the fitted parameters but also a measure of the goodness of fit. With unbinned data, currently, the fitted parameters are obtained but no measure of goodness of fit is available. This remains, to date, an unsolved problem in stati

S. S. Avancini, F. F. de Souza Cruz, J. R. Marinelli, D. P. Menezes

In this work we develop a formalism to treat quons restricted to the antisymmetric part of their many-body space. A model in which a system of identical quons interact through a pairing force is then solved within this restriction and the differences between our solution and the usual fermionic model solution are then presented and discussed in detail. Possi

I. G. Aznauryan

We present the results on the ratios $E_{1+}^{(3/2)}/M_{1+}^{(3/2)}$ and $S_{1+}^{(3/2)}/M_{1+}^{(3/2)}$ for the $γ^* N \to Δ(1232)$ transition at $Q^2\leq 4 (GeV/c)^2$ extracted from the $p(e,e&#39;p)π^0$ cross section using two approaches: dispersion relations and modified version of unitary isobar model. The obtained results are in good agreement with the

A. Dote, H. Horiuchi, Y. Akaishi, T. Yamzaki

Using a phenomenological KN potential which reproduces $Λ$(1405) as an I=0 bound state of KN, we investigated deeply bound kaonic nuclei, ppnK$^-$ and $^8$BeK$^-$, with the method of Antisymmetrized Molecular Dynamics. Our calculations show that strongly bound kaonic nuclear systems with unusual exotic structures are formed around the K$^-$, which attracts t

R. Salazar, A. P. J. Jansen, V. N. Kuzovkov

We present a parallel implementation of cellular automata to simulate chemical reactions on surfaces. The scaling of the computer time with the number of processors for this parallel implementation is quite close to the ideal T/P, where T is the computer time used for one single processor and P the number of processors. Two examples are presented to test the

Krzysztof Gawedzki

Introductory lectures on the Kraichnan model of passive advection

Sergio Albeverio, Debashish Goswami

We study the structure of the generator of a symmetric, conservative quantum dynamical semigroup with norm-bounded generator on a von Neumann algebra equipped with a faithful semifinite trace. For von Neumann algebras with abelian commutant (i.e. type I von Neumann algebras), we give a necessary and sufficient algebraic condition for the generator of such a

J. -P. Eckmann, M. Hairer

We study hypoelliptic operators with polynomially bounded coefficients that are of the form K = sum_{i=1}^m X_i^T X_i + X_0 + f, where the X_j denote first order differential operators, f is a function with at most polynomial growth, and X_i^T denotes the formal adjoint of X_i in L^2. For any e > 0 we show that an inequality of the form |u|_{delta,delta} <=

Debashish Goswami

We study various noncommutative geometric aspects of the compact quantum group SU_q(2) for positive q (not equal to 1), following the suggestion of Connes and his coauthors [CL, CD] for considering the so-called true Dirac operator. However, it turns out that the method of the above references do not extend to the case of positive (not equal to 1) values of

Yves Edel, E. M. Rains, N. J. A. Sloane

An elementary construction using binary codes gives new record kissing numbers in dimensions from 32 to 128.

Vinay A. Vaishampayan, N. J. A. Sloane, Sergio D. Servetto

The problem of designing a multiple description vector quantizer with lattice codebook Lambda is considered. A general solution is given to a labeling problem which plays a crucial role in the design of such quantizers. Numerical performance results are obtained for quantizers based on the lattices A_2 and Z^i, i=1,2,4,8, that make use of this labeling algor

Tonia Ricciardi

We define an abstract nonlinear elliptic system, admitting a variational structure, and including the vortex equations for some Maxwell-Chern-Simons gauge theories as special cases. We analyze the asymptotic behavior of its solutions, and we provide a general simplified framework for the asymptotics previously derived in those special cases. As a byproduct o

J. M. Landsberg

I show that any complex manifold that resembles a rank two compact Hermitian symmetric space (other than a quadric hypersurface) to order two at a general point must be an open subset of such a space.

J. M. Aldaz, Juan L. Varona

We show that in the study of certain convolution operators, functions can be replaced by measures without changing the size of the constants appearing in weak type (1,1) inequalities. As an application, we prove that the best constants for the centered Hardy-Littlewood maximal operator associated to parallelotopes do not decrease with the dimension.

Annette Huber, Guido Kings

This is a contribution to the ICM 2002. We explain the relation between the (equivariant) Bloch-Kato conjecture for special values of L-functions and the Main Conjecture of (non-abelian) Iwasawa theory. On the way we will discuss briefly the case of Dirichlet characters in the abelian case. We will also discuss how "twisting" in the non-abelian case would al

Seok-Jin Kang

In this paper, we give a realization of crystal bases for quantum affine algebras using some new combinatorial objects which we call the Young walls. The Young walls consist of colored blocks with various shapes that are built on the given ground-state wall and can be viewed as generalizations of Young diagrams. The rules for building Young walls and the act

David Kerr

We develop a matricial version of Rieffel&#39;s Gromov-Hausdorff distance for compact quantum metric spaces within the setting of operator systems and unital C*-algebras. Our approach yields a metric space of ``isometric&#39;&#39; unital complete order isomorphism classes of metrized operator systems which in many cases exhibits the same convergence properti

Tim Dokchitser

We present an algorithm to compute values L(s) and derivatives of L-functions of motivic origin numerically to required accuracy. Specifically, the method applies to any L-series whose Gamma-factor is a product of any number of Gamma-functions Gamma((s+l(j))/2) with complex l(j), not necessarily distinct. The algorithm relies on the known (or conjectural) fu

Marco Mackaay

Recently twisted K-theory has received much attention due to its applications in string theory and the announced result by Freed, Hopkins and Telemann relating the twisted equivariant K-theory of a compact Lie group to its Verlinde algebra. Rather than considering gerbes as separate objects, in twisted K-theory one considers a gerbe as being part of the data