February 2003 arXiv papers — page 7

Sampsa Fabritius, Raimondas Lencevicius, Edu Metz, Alexander Ran

This paper describes a new approach to experimentally estimate the application schedulability for various processor frequencies. We use additional workload generated by an artificial high priority routine to simulate the frequency decrease of a processor. Then we estimate the schedulability of applications at different frequencies. The results of such estima

J. J. Heremans, A. O. Govorov, D. Kantha, Z. Nikodijevic

We describe both experimentally and theoretically a hydrodynamic pumping mechanism in a Fermi liquid, arising from electron-electron interaction. An electron beam sweeping past an aperture is observed to pump carriers from this aperture. Experimentally, the pumping effect induces a current in the lead connected to the aperture, or induces a voltage signal co

J. E. McCrone, J. L. Tallon, J. R. Cooper, A. C. MacLaughlin

RuSr$_2$GdCu$_2$O$_8$, in which magnetic order and superconductivity coexist with $T_{Magnetic}$$\gg$$T_c$, is a complex material which poses new and important questions to our understanding of the interplay between magnetic and superconducting (SC) order. Resistivity, Hall effect and thermopower measurements on sintered ceramic RuSr$_2$GdCu$_2$O$_8$ are pre

Gil Refael, Eugene Demler, Yuval Oreg, Daniel S. Fisher

A model system consisting of a mesoscopic superconducting grain coupled by Josephson junctions to two macroscopic superconducting electrodes is studied. We focus on the effects of ohmic dissipation caused by resistive shunts and superconducting-normal charge relaxation within the grain. As the temperature is lowered, the behavior crosses over from uncoupled

S. Yeo, S. Nakatsuji, A. D. Bianchi, P. Schlottmann

The phase diagram of FeSi1-xGex, obtained from magnetic, thermal and transport measurements on single crystals, shows a first-order transition from a correlated electron semiconductor to a ferromagnetic metal at a critical concentration, x ~ 0.25. The gap of the insulating phase strongly decreases with x. The specific heat coefficient appears to track the de

S. A. Prosandeev, I. P. Raevski, U. V. Waghmare

In this paper, we present a microscopic model for heterogeneous ferroelectric and an order parameter for relaxor phase. We write a Landau theory based on this model and its application to ferroelectric PbFe$_{1/2}$Ta$_{1/2}$O$_3$ (PFT) and antiferroelectric NaNbO$_3$:Gd. We later discuss the coupling between soft mode and domain walls, soft mode and quasi-lo

F. J. Cherne, M. I. Baskes, R. B. Schwarz, S. G. Srinivasan

The dynamics of homogeneous nucleation and growth of crystalline nickel from the super-cooled melt is examined during rapid quenching using molecular dynamics and a modified embedded atom method potential. The character of the critical nuclei of the crystallization transition is examined using common neighbor analysis and visualization. At nucleation the sad

A. Podesta', G. Fantoni, P. Milani

Atomic Force Microscopy (AFM) is a suitable tool to perform tribological characterization of materials down to the nanometer scale. An important aspect in nanofriction measurements of corrugated samples is the local tilt of the surface, which affects the lateral force maps acquired with the AFM. This is one of the most important problems of state-of-the-art

Kwan-Woo Lee, W. E. Pickett

Calculations of the zone center optical mode frequencies (including LO-TO splitting), Born effective charges Z$^*_{αα}$ for each atom, dielectric constants $ε_{0}$ and $ε_{\infty}$, and the dielectric response in the infrared, using density functional linear response theory, are reported. Calculated Raman modes are in excellent agreement with experimental va

W. Knafo, S. Raymond, B. Fak, G. Lapertot

Inelastic neutron scattering experiments were performed on single crystals of the heavy-fermion compound CeIn$_{3}$ for temperatures below and above the Néel temperature, $T_N$. In the antiferromagnetically ordered phase, well-defined spin-wave excitations with a bandwidth of 2 meV are observed. The spin waves coexist with quasielastic (QE) Kondo-type spin-f

X. J. Chen, H. -U. Habermeier, C. L. Zhang, H. Zhang

The temperature $T$ and magnetic field $H$ dependence of the resistivity $ρ$ has been measured for La$_{0.8-y}$Sr$_{0.2}$MnO$_{3}$ (y=0 and 0.128) films grown on (100) SrTiO$_{3}$ substrates. The low-temperature $ρ$ in the ferromagnetic metallic region follows well $ρ(H,T)=ρ_{0}(H)+A(H)ω_{s}/\sinh (\hbar ω_{s}/2k_{B}T)+B(H)T^{7/2}$ with $ρ_{0}$ being the res

Edward McCann, Vladimir I. Fal'ko

We develop a theoretical model of magnon-assisted transport in a mesoscopic tunnel junction between a ferromagnetic metal and a normal (non-magnetic) metal. The current response to a bias voltage is dominated by the contribution of elastic processes rather than magnon-assisted processes and the degree of spin polarization of the current, parameterized by a f

M. I. Dykman, Leonid P. Pryadko

We study the conductivity of a nondegenerate 2D electron liquid in a quantizing magnetic field for frequencies well below the cyclotron frequency. The conductivity is formed by electron transitions in which the energy of a photon goes to the interaction energy of the many-electron system, whereas the involved momentum is transferred to quenched disorder. The

Malte Henkel

Building on an analogy with conformal invariance, local scale transformations consistent with dynamical scaling are constructed. Two types of local scale invariance are found which act as dynamical space-time symmetries of certain non-local free field theories. The scaling form of two-point functions is completely fixed by the requirement of local scale inva

Gergely Zarand, Arne Brataas, David Goldhaber-Gordon

We study strongly correlated states in triangular artificial atoms. Symmetry-driven orbital degeneracy of the single particle states can give rise to an SU(4) Kondo state with entangled orbital and spin degrees of freedom, and a characteristic phase shift $δ= π/4$. Upon application of a Zeeman field, a purely orbital Kondo state is formed with somewhat small

S. Friedli, C. -E. Pfister

We study the analyticity properties of the free energy $f_\ga(m)$ of the Kac model at points of first order phase transition, in the van der Waals limit $\ga\searrow 0$. We show that there exists an inverse temperature $β_0$ and $\ga_0>0$ such that for all $β\geq β_0$ and for all $\ga\in(0,\ga_0)$, $f_\ga(m)$ has no analytic continuation along the path $m\se

R. Fiederling, P. Grabs, W. Ossau, G. Schmidt

Detection of the degree of circular polarization of the electroluminescence of a light-emitting diode fitted with a spin injecting contact (a spin-LED) allows for a direct determination of the spin polarization of the injected carriers. Here, we compare the detection efficiency of (Al,Ga)As spin-LEDs fitted with a (Zn,Be,Mn)Se spin injector in top- and side-

Claire Sellier, Florent Boucher, Etienne Janod

Single crystal X-ray diffraction measurements were performed on one-dimensional mixed valence vanadium bronze $β$-SrV$_6$O$_{15}$ in which a metal-insulator transition exists at 170 K. Above 170 K the P2$_1$/a structure with zigzag order of Sr in the tunnels of vanadium is confirmed. In the structure below 170 K, the P2$_1$/a space group is retained with a b

I. Felner, V. P. S. Awana, E. Takayama-Muromachi

We have studied the magnetic properties of the non-superconducting RuSr2Ln1.5Ce0.5Cu2O10 (Ln=Y, Dy and Ho, Ru-1222) compounds synthesized under high pressure (6 Gpa) at elevated temperature. The materials become magnetically ordered at TM =152(2) K regardless of Ln. The wide ferromagnetic-like hysteresis loops which open at 5 K, close themselves around Tirr=

G. Oshanin, O. Benichou, A. Blumen

We present an exact solution describing equilibrium properties of the catalytically-activated A + A \to 0 reaction taking place on a one-dimensional lattice, where some of the sites possess special "catalytic" properties. The A particles undergo continuous exchanges with the vapor phase; two neighboring adsorbed As react when at least one of them res

Khee-Kyun Voo, Hong-Yi Chen, W. C. Wu

Motivated by recent angle-resolved photoemission spectroscopy (ARPES) measurement that superconducting YBa$_2$Cu$_3$O$_{7-δ}$ (YBCO) exhibits a $d_{x^2-y^2} + s$-symmetry gap, we show possible quasi-one-dimensional modulations of local density of states in YBCO. These aniostropic gap and defect induced stripe structures are most conspicuous at higher biases

D. Baigl, R. Ober, D. Qu, A. Fery

The combination of two techniques (Small Angle X-ray Scattering and Atomic Force Microscopy) has allowed us to measure in reciprocal and real space the correlation length $ξ$ of salt-free aqueous solutions of highly charged hydrophobic polyelectrolyte as a function of the polymer concentration $C_p$, charge fraction $f$ and chain length $N$. Contrary to the

Tetsuro Saso, Hisatomo Harima

A new LDA+U band calculation is performed on the Kondo insulator material YbB$_{12}$ and an energy gap of about 0.001Ryd is obtained. Based on this, a simple tight-binding model with 5d$ε$ and 4f $Γ_8$ orbitals on Yb atoms and the nearest neighbor $σ$-bonds between them is constructed with a good agreement to the above the LDA+U calculation near the gap. The

M. Karppinen, M. Kotiranta, T. Nakane, H. Yamauchi

Induction of holes not only in the superconductive CuO2 plane but also in the Bi2O2+d charge reservoir of the Bi2Sr2(Y1-xCax)Cu2O8+d superconductor upon CaII-for-YIII substitution is evidenced by means of two independent techniques, i.e., high-resolution x-ray-absorption near-edge structure (XANES) spectroscopy measurements and coulometric redox titrations.

I. Yang, W. Kang, S. T. Hannahs, L. N. Pfeiffer

We have observed an anomalous shift of the high field reentrant insulating phases in a two-dimensional electron system (2DES) tightly confined within a narrow GaAs/AlGaAs quantum well. Instead of the well-known transitions into the high field insulating states centered around $ν= 1/5$, the 2DES confined within an 80Å-wide quantum well exhibits the transition

G. P. Zhang, G. S. Chang, T. A. Callcott, D. L. Ederer

Angle-resolved soft x-ray measurements made at the boron K-edge in single crystal MgB2 provide new insights into the B-2p local partial density of both unoccupied and occupied band states. The strong variation of absorption with incident angle of exciting x-rays permits the clear separation of contributions from σstates in the boron plane and πstates normal

A. A. Koulakov, M. E. Raikh

A classical model for {\em dc} transport of two dimensional electrons in a perpendicular magnetic field and under strong irradiation is considered. We demonstrate that, near the cyclotron resonance condition, and for {\em linear} polarization of the {\em ac} field, a strong change of the diagonal component, $σ_d$, of the {\em dc} conductivity occurs in the p

J. D. Albrecht, D. L. Smith

We theoretically investigate electron spin injection and spin-polarization sensitive current detection at Schottky contacts between a ferromagnetic metal and an n-type or p-type semiconductor. We use spin-dependent continuity equations and transport equations at the drift-diffusion level of approximation. Spin-polarized electron current and density in the se

P. Nikunen, M. Karttunen, I. Vattulainen

In this work we assess the quality and performance of several novel dissipative particle dynamics integration schemes that have not previously been tested independently. Based on a thorough comparison we identify the respective methods of Lowe and Shardlow as particularly promising candidates for future studies of large-scale properties of soft matter system

Claude M. Dion, Eric Cances

We study the numerical resolution of the time-dependent Gross-Pitaevskii equation, a non-linear Schroedinger equation used to simulate the dynamics of Bose-Einstein condensates. Considering condensates trapped in harmonic potentials, we present an efficient algorithm by making use of a spectral Galerkin method, using a basis set of harmonic oscillator functi

J. Cho, A. Lazarian, A. Honein, B. Knaepen

Using numerical methods, we systematically study in the framework of ideal MHD the effect of magnetic fields on heat transfer within a turbulent gas. We measure the rates of passive scalar diffusion within magnetized fluids and make the comparisons a) between MHD and hydro simulations, b) between different MHD runs with different values of the external magne

Simon Johnston

Radio observations of two isolated neutron stars, RXJ0720.4-3125 and RX J0806.4-4132, have been made with the Australia Telescope Compact Array at a frequency of 1.4 GHz. No continuum emission is detected from either object with a 3 sigma upper limit of 0.2 mJy. The data were also folded synchronously with the known rotation periods of 8.4 and 11.4 s respect

P. Sokolsky, J. Krizmanic

Space-based ultra-high-energy cosmic ray detectors observe fluorescence light from extensive air showers produced by these particles in the troposphere. Clouds can scatter and absorb this light and produce systematic errors in energy determination and spectrum normalization. We study the possibility of using IR remote sensing data from MODIS and GOES satelli

P. F. Bloser, F. Schopper, R. Andritschke, G. Kanbach

We report on the design, production, and testing of advanced double-sided silicon strip detectors under development at the Max-Planck-Institute as part of the Medium Energy Gamma-ray Astronomy (MEGA) project. The detectors are designed to form a stack, the "tracker," with the goal of recording the paths of energetic electrons produced by Compton-scat

N. Manset, P. Bastien

We present polarimetric observations of 7 pre-main-sequence (PMS) spectroscopic binaries located in the rho Oph and Upper Sco star forming regions (SFRs). The average observed polarizations at 7660A are between 0.5% and 3.5%. After estimates of the interstellar polarization are removed, all binaries have an intrinsic polarization above 0.4%. Two binaries, NT

Oleg Y. Gnedin

Tidal forces acting on galaxies in clusters lead to a strong dynamical evolution. In order to quantify the amount of evolution, I run self-consistent N-body simulations of disk galaxies for a variety of models in the hierarchically forming clusters. The tidal field along the galactic orbits is extracted from the simulations of cluster formation in the Omega_

Oleg Y. Gnedin

High-redshift clusters of galaxies show an over-abundance of spirals by a factor of 2-3, and the corresponding under-abundance of S0 galaxies, relative to the nearby clusters. This morphological evolution can be explained by tidal interactions with neighboring galaxies and with the hierarchically growing cluster halo. The efficiency of tidal interactions dep

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

We examine rest-frame ultraviolet spectra of 70 high redshift quasars (z>3.5) to study the chemical enrichment history of the gas closely related to the quasars, and thereby estimate the epoch of first star formation. The fluxes of several ultraviolet emission lines were investigated within the framework of the most recent photoionization models to estimate

K. C. Steenbrugge, J. S. Kaastra, C. P. de Vries, R. Edelson

We analyze a 137 ks exposure X-ray spectrum of the Seyfert 1 galaxy NGC 5548 obtained with the XMM-Newton Reflection Grating Spectrometer. Due to the long exposure time, the spectrum is of higher statistical quality than the previous observations of this AGN. Therefore, we detect for the first time in NGC 5548 inner-shell transitions from O III to O VI ions,

E. J. Delgado-Donate, C. Munoz-Tunon, H. J. Deeg, J. Iglesias-Paramo

We present results from a survey of dwarf galaxy candidates in the vicinity of strongly interacting galaxies. The goal of the survey was a test of the hypothesis that massive condensations of stars and HI in tidal tails of large interacting galaxies may be a significant source of independent, self-gravitating dwarf galaxies. These so called tidal dwarf galax

Nanda Rea, Gian Luca Israel, Luigi Stella, Tim Oosterbroek

We report the results of a long observation of the anomalous X-ray pulsar 1RXS J170849-400910 obtained with the BeppoSAX satellite in August 2001. The best-fit phase-averaged spectrum was an absorbed power law plus blackbody model, with photon index Gamma~2.4 and a blackbody temperature of kT_bb~0.4 keV. We confirm the presence of significant spectral variat

F. Halzen

Although cosmic rays were discovered a century ago, we do not know where or how they are accelerated. There is a realistic hope that the oldest problem in astronomy will be solved soon by ambitious experimentation: air shower arrays of 10,000 kilometer-square area, arrays of air Cerenkov telescopes and kilometer- scale neutrino observatories. Their predecess

Rene' Liseau, Alexis Brandeker, Malcolm Fridlund, Goeran Olofsson

We present millimeter imaging observations in the 1200 micron continuum of the disk around beta Pictoris. With the 25 arcsec beam, the beta Pic disk is unresolved perpendicularly to the disk plane (< 10 arcsec), but slightly resolved in the northeast-southwest direction (26 arcsec). Peak emission is observed at the stellar position. A secondary maximum is fo

C. Marmo, L. Secco

In a gravitational virialized bound system built up of two components, one of which is embedded in the other, the Clausius&#39; virial energy of one subcomponent is not, in general, equal to its total potential energy, as occurs in a single system without external forces. This is the main reason for the presence, in the case of two non-coinciding concentric

Henri M. J. Boffin, Dimitri Pourbaix

In paper 167 of his serie published in The Observatory, Griffin presented the spectroscopic orbit of HD 112914, a late main sequence star. He also noticed that this star, also known as HIP 63406, was one of the few for which the DMSA/O Annex of the Hipparcos Catalogue derived an orbit prior to any spectroscopic one. Albeit in agreement with each others, the

Izumi Hachisu, Mariko Kato

A new self-sustained model for long-term light curve variations of RX J0513.9-6951 is proposed based on an optically thick wind model of mass-accreting white dwarfs (WDs). When the mass accretion rate to a WD exceeds the critical rate of \sim 1 x 10^{-6} M_\sun yr^{-1}, optically thick strong winds begin to blow from the WD so that a formation of common enve

International Gravitational Event Collaboration

This paper presents the results of the observations of the detectors participating in the International Gravitational Event Collaboration (IGEC) from 1997 to 2000 and reviews the data analysis methods. The analysis is designed to search for coincident excitations in multiple detectors. The data set analysed in this article covers a longer period and is more

Paul A. Crowther, Peter S. Conti

We present mid-IR 21micron images of a sample of radio selected Ultracompact HII (UCHII) regions, obtained with the Midcourse Space Experiment (MSX). All, with one possible exception, are detected at mid-IR wavelengths, sampling the warm dust emission of the cocoons of the OB star central exciting sources. Many of the UCHII regions have nearby (up to a few p

Silvia Petroni, Giuseppe Bono

We present an overview on pulsation properties of RR Lyrae stars in the Galaxy and in Local Group dwarf galaxies. We discuss the key information that RR Lyrae might provide on their parent population, and in particular on their metallicity distribution.

A. J. Gawryszczak, M. Rozyczka

We present three-dimensional models of accretion disks in U Gem - like systems and calculate their Doppler tomograms. The tomograms are based on two different assumptions concerning the origin of line emission from the disk. The assumption of lines originating due to irradiation of the surface layer of the disk by the central source leads to a better agreeme

F. Gueth, R. Bachiller, M. Tafalla

We present new high-sensitivity 1.3 mm bolometer observations of the young outflow L1157. These data show that the continuum emission arises from four distinct components: a circumstellar disk, a protostellar envelope, an extended flattened envelope --the dense remnant of the molecular cloud in which the protostar was formed--, and the outflow itself, which

R. T. Edwards, B. W. Stappers, A. G. J. van Leeuwen

We report on an analysis of the drifting subpulses of PSR B0320+39 that indicates a sudden step of ~180 degrees in subpulse phase near the centre of the pulse profile. The phase step, in combination with the attenuation of the periodic subpulse modulation at pulse longitudes near the step, suggests that the patterns arise from the addition of two superposed

Mike J. Cai, Frank H. Shu

We construct self-similar, axisymmetric, time-independent solutions to Einstein&#39;s field equations for an isothermal gas with a flat rotation curve in the equatorial plane. The metric scales as $ds^2 \to a^2 ds^2$ under the transformation $r\to a r$ and $t \to a^{1-n} t$, where $n$ is a dimensionless measure of the strength of the gravitational field. The

S. S. Fujita, M. Ajiki, Y. Shioya, T. Nagao

We have carried out a deep imaging survey for H$α$ emitting galaxies at $z\approx$0.24 using a narrowband filter tuned with the redshifted line. The total sky area covered is 706 arcmin$^2$ within a redshift range from 0.234 to 0.252 ($δz$=0.018). This corresponds to a volume of 3.9$\times10^3$ Mpc$^3$ when $Ω_{\rm matter}=0.3$, $Ω_Λ=0.7$, and $H_{\mathrm{0}

Yoichi Itoh, Koji Sugitani, Naoya Fukuda, Kouichiro Nakanishi

We have carried out a millimeter interferometric continuum survey toward 7 YSOs in the MBM 12 cloud. Thermal emissions associated with 2 YSOs were detected above the 3-$σ$ level at 2.1 mm, and one also showed a 1.3 mm thermal emission. Another object was marginally detected at 2.1 mm. Spectral energy distributions of the YSOs are well fitted by a simple powe

Andrej Prsa

Because of GAIA&#39;s estimated harvest of cca. 10^5 eclipsing binaries (Munari et al. 2001) automative procedures for extracting physical parameters from observations must be introduced. We present preliminary results of automative scripting applied to 5 eclipsing binaries, for which photometric and radial velocity observations were taken from literature. A

Patrizia Rossi

The CLAS collaboration in Hall B at the Thomas Jeffeson National Accelerator Facility (Jefferson Lab) has a broad scientific program. Recent results on the main topics are presented. These concern the electromagnetic exitation of nucleon resonances, the measurement of inclusive spin structrure functions in the nucleon resonance region, the first signature of

Masoud Soroush

In this paper, the BRST symmetry transformation is presented for the noncommutative U(N) gauge theory. The nilpotency of the charge associated to this symmetry is then proved. As a consequence for the space-like non-commutativity parameter, the Hilbert space of physical states is determined by the cohomology space of the BRST operator as in the commutative c

Lie-Wen Chen, Che Ming Ko, Bao-An Li

Using an isospin-dependent transport model for heavy-ion collisions induced by neutron-rich nuclei at intermediate energies, we study the production of light clusters such as deuteron, triton, and $^{3}$He via coalescence of nucleons. We find that both the yields and energy spectra of these light clusters are affected significantly by the density dependence

Hadi Salehi

For an effective treatment of the evaporation process of a large black hole the problem concerning the role played by the fluctuations of the (vacuum) stress tensor close to the horizon is addressed. We present arguments which establish a principal relationship between the outward fluctuations of the stress tensor close to the horizon and quantities describi

Tomohiro Matsuda

In this paper we show that certain types of cosmological brane configurations may induce topological inflation. In generic models for topological inflation, there is a strict bound for the potential of the inflaton field. Naively, it seems that these constraints can be removed if inflation starts with a hybrid potential. However, it is difficult to combine t

Marcelo Aguiar, Nantel Bergeron, Kathryn Nyman

We show the existence of a unital subalgebra of the symmetric group algebra linearly spanned by sums of permutations with a common peak set, which we call the peak algebra. We show that this algebra is the image of the descent algebra of type B under the map to the descent algebra of type A which forgets the signs, and also the image of the descent algebra o

S. L Arsenjev, I. B. Lozovitski, Y. P. Sirik

It is shown, that the introduction in Saint-Venant -Wantzel formula radicand of the free component in the form of quadrate of velocity of the incident gas flow on inlet of flowing element that was offered in the end of the XIX century and is remained till now it is physically inadequate. It is shown that this way is doubtful for hydromechanics and it absolut

Xiang Li, Changyu Hu, Jie Liang

Protein representation and potential function are essential ingredients for studying proteins folding and protein prediction. We introduce a novel geometric representation of contact interactions using the edge simplices from alpha shape of protein structure. This representation can eliminate implausible neighbors not in physical contact, and can avoid spuri

G. Penner, U. Mosel

We present a nucleon resonance analysis by simultaneously considering all pion- and photon-induced experimental data on the final states $γN$, $πN$, $2πN$, $ηN$, $KΛ$, $KΣ$, and $ωN$ for energies from the nucleon mass up to $\sqrt s = 2$ GeV. In this analysis we find strong evidence for various higher lying resonances as, e.g., the $P_{13}(1900)$. The $ωN$ p

G. Iovane, M. Ciarletta

In this paper a treatment of hypersingular integral equations, which have relevant applications in many problems of wave dynamics, elasticity and fluid mechanics with mixed boundary conditions, is presented. The main goal of the present work is the development of an efficient direct numerical collocation method. The second part of the work is devoted to the

Christopher J. Leininger

We consider various equivalence relations on the set of homotopy classes of curves on a hyperbolic surface based on topological, algebraic, and geometric structures. The purpose of this work is to determine the relationship between these equivalences.

Bertrand Remy, Patrick Bonvin

We provide new arguments to see topological Kac-Moody groups as generalized semisimple groups over local fields: they are products of topologically simple groups and their Iwahori subgroups are the normalizers of the pro-p Sylow subgroups. We use a dynamical characterization of parabolic subgroups to prove that some countable Kac-Moody groups with Fuchsian b

H. Garcia-Compean, O. Obregon, C. Ramirez, M. Sabido

Starting from a self-dual formulation of gravity, we obtain a noncommutative theory of pure Einstein theory in four dimensions. In order to do that, we use Seiberg-Witten map. It is shown that the noncommutative torsion constraint is solved by the vanishing of commutative torsion. Finally, the noncommutative corrections to the action are computed up to secon

S. N. Gninenko, N. V. Krasnikov, A. Rubbia

We point out that some models with infinite additional dimension(s) of Randall-Sundrum type predict the disappearance of orthopositronium (o-Ps) into additional dimension(s). The experimental signature of this effect is the o-Ps -> invisible decay of orthopositronium which may occur at a rate within three orders of magnitude of the present experimental upper

Juan Estrada

We present a novel approach that is being developed at DZero for extracting information from data through a direct comparison of all measured variables in an event with a matrix element that describes the entire production process. The method is exemplified in the extraction of the mass of the top quark in top-antitop events in the lepton+jets final state. M

Pierre Albarede

This article aims at clarifying the language and practice of scientific experiment, mainly by hooking observability on calculability.

Michael Zemcov, Peter Newbury, Mark Halpern

We present estimates of the confusion limit of measurements of the Sunyaev-Zel&#39;dovich effect (SZ) increment near its peak intensity based on Monte Carlo simulations of sub-millimetre observations of galaxy clusters. Specifically, we evaluate the contribution of gravitational lensing of high redshift background sources by a target cluster to its inferred

Zdzislaw A. Golda, Andrzej Woszczyna

Adiabatic perturbations propagate in the expanding universe like scalar massless fields in some effective Robertson-Walker space-time.

A. Wozna, L. Kuiper, W. Hermsen

This article has been withdrawn because it was submitted twice unintentionally.

Ningdong Huang, Zhirong Liu, Zhongqing Wu, Jian Wu

Monte Carlo simulations based on a first-principles-derived Hamiltonian are conducted to study the properties of PZT alloys compositionally modulated along the [100] pseudocubic direction near the morphotropic phase boundary (MPB). It is shown that compositional modulation causes the polarization to continuously rotate away from the modulation direction, res

Louis-Philippe Lamoureux, Patrick Navez, Jaromir Fiurasek, Nicolas J. Cerf

It is shown that any quantum operation that perfectly clones the entanglement of all maximally-entangled qubit pairs cannot preserve separability. This ``entanglement no-cloning&#39;&#39; principle naturally suggests that some approximate cloning of entanglement is nevertheless allowed by quantum mechanics. We investigate a separability-preserving optimal cl

Yafei Yu, Jian Feng, Mingsheng Zhan

In this short note, we propose a scheme, in which two instances of an equatorial state (or a polar state) can be remotely prepared in one-shot operation to different receivers with prior entanglement and 1 bit of broadcasting. The trade-off curve between the amount of entanglement and the achievable fidelity is derived.

Michael Levin, Xiao-Gang Wen

We investigate the general properties of lattice spin models with emerging fermionic excitations. We argue that fermions always come in pairs and their creation operator always has a string-like structure with the newly created particles appearing at the endpoints of the string. The physical implication of this structure is that the fermions always couple to

X. -G. He, A. Zee

It is well known that the neutrino mass matrix contains more parameters than experimentalists can hope to measure in the foreseeable future even if we impose CP invariance. Thus, various authors have proposed ansatzes to restrict the form of the neutrino mass matrix further. Here we propose that $m_{ν_1} + m_{ν_2} + m_{ν_3} = 0$; this ``zero sum&#39;&#39; co

V. P. Nair, A. Yelnikov

We consider a gauge-invariant Hamiltonian analysis for Yang-Mills theories in three spatial dimensions. The gauge potentials are parametrized in terms of a matrix variable which facilitates the elimination of the gauge degrees of freedom. We develop an approximate calculation of the volume element on the gauge-invariant configuration space. We also make a ro

Itai Benjamini, David B. Wilson

A random walk on Z^d is excited if the first time it visits a vertex there is a bias in one direction, but on subsequent visits to that vertex the walker picks a neighbor uniformly at random. We show that excited random walk on Z^d, is transient iff d>1.

S. A. Khodykin, A. I. Zakharov, W. L. Andersen

It is well established that certain detached eclipsing binary stars exhibit apsidal motions whose value is in disagreement with with calculated deviations from Keplerian motion based on tidal effects and the general theory of relativity. Although many theoretical senarios have been demonstrated to bring calculations into line with observations, all have seem

Patrick Navez, Nicolas J. Cerf

We investigate a new class of quantum cloning machines that equally duplicate all real states in a Hilbert space of arbitrary dimension. By using the no-signaling condition, namely that cloning cannot make superluminal communication possible, we derive an upper bound on the fidelity of this class of quantum cloning machines. Then, for each dimension d, we co

P. K. Panigrahi, T. Shreecharan, J. Banerji, V. Sundaram

A general procedure for constructing coherent states, which are eigenstates of annihilation operators, related to quantum mechanical potential problems, is presented. These coherent states, by construction are not potential specific and rely on the properties of the orthogonal polynomials, for their derivation. The information about a given quantum mechanica

G. R. Jin, D. L. Zhou

This paper has been withdrawn by the author(s), due a crucial sign error in conclusion .

P. Ao

Dynamics near and far away from thermal equilibrium is studied within the framework of Langevin equations. A stochasticity-dissipation relation is proposed to emphasize the equal importance of the stochastic and deterministic forces in describing the system&#39;s evolution and destination. It is a generalization of the fluctuation-dissipation theorem. Close

Valerio Lucarini, Kai Erik Peiponen

We present the first analysis of harmonic generation data where the full potential of the generalized nonlinear Kramers-Kronig (K-K) relations and sum rules is exploited. We consider two published sets of wide spectral range experimental data of third harmonic generation susceptibility on different polymers, the polysilane (frequency range: $0.4-2.4$ $eV$) a

V. V. Yashchuk, D. Budker, W. Gawlik, D. F. Kimball

We describe a method of selective generation and study of polarization moments of up to the highest rank $κ=2F$ possible for a quantum state with total angular momentum $F$. The technique is based on nonlinear magneto-optical rotation with frequency-modulated light. Various polarization moments are distinguished by the periodicity of light-polarization rotat

Boris Ivlev

The extremely small probability of quantum tunneling through an almost classical potential barrier may become not small under the action of the specially adapted nonstationary field. The tunneling rate has a sharp peak as a function of the particle energy when it is close to the certain resonant value defined by the nonstationary field (Euclidean resonance).

C. Forssén, N. B. Shul&#39;gina, M. V. Zhukov

Electromagnetic processes in loosely bound nuclei are investigated using an analytical model. In particular, electromagnetic dissociation of $^8$B is studied and the results of our analytical model are compared to numerical calculations based on a three-body picture of the $^8$B bound state. The calculation of energy spectra is shown to be strongly model dep

Grzegorz Litak, Michael I. Friswell

Gear box dynamics is characterised by a periodically changing stiffness and a backlash which can lead to a loss of the contact between the teeth. Due to backlash, the gear system has piecewise linear stiffness characteristics and, in consequence, can vibrate regularly or chaoticaly depending on the system parameters and the initial conditions. We examine the

Nail R. Khusnutdinov

An uniform expansion of the Legendre functions of large indices are considered by using the WKB approach. We obtain the recurrent formula for the coefficients of uniform expansion and compare them with the uniform expansion of the Bessel function.

Sergey Leble

Links of factorization theory, supersymmetry and Darboux transformations as isospectral deformations are considered in the context of quantum theory. The infinite chain equations for factorizing operators for a spectral problem are derived. A closure of the chain defines a symmetry of the system. Examples of matrix-differential operators of Pauli and Dirac t

Wang Gongbao, Ma Jipu

The complete characterizations of the spectra and their various parts of hyponormal unilateral and bilateral weighted shifts are presented respectively in this paper. The results obtained here generalize the corresponding work of the references.

Wang Gongbao, Ma Jipu

In this note, necessary and sufficient conditions are obtained for unilateral weighted shifts to be near subnormal . As an application of the main results, many answers to the Hilbert space problem 160 are presented at the end of the paper.

David J. Benson, Alex Kumjian, N. Christopher Phillips

Let A be a separable unital nuclear purely infinite simple C*-algebra satisfying the Universal Coefficient Theorem, and such that the K_0-class of the identity is zero. We prove that every automorphism of order two of the K-theory of A is implemented by an automorphism of A of order two. As a consequence, we prove that every countable Z/2Z-graded module over

Nicolas Monod, Sorin Popa

We first show that co-amenability does not pass to subgroups, answering a question asked by Eymard in 1972. We then address co-amenability for von Neumann algebras, describing notably how it relates to the former.

C. S. Rajan

We generalize a theorem of Tate and show that the second cohomology of the Weil group of a global or local field with coefficients in $\C^*$ (or more generally, with coefficients in the complex points of a tori over $\C$) vanish, where the cohomology groups are defined using measurable cochains in the sense of Moore. We recover a theorem of Labesse proving t

Gilles Pisier

We prove that the operator Hilbert space OH does not embed completely isomorphically into the predual of a semi-finite von Neumann algebra. This complements Junge&#39;s recent result that it admits such an embedding in the non semi-finite case.