June 2005 arXiv papers — page 4

Warren G. Anderson, Alan G. Wiseman

We discuss a practical method to compute the self-force on a particle moving through a curved spacetime. This method involves two expansions to calculate the self-force, one arising from the particle's immediate past and the other from the more distant past. The expansion in the immediate past is a covariant Taylor series and can be carried out for all g

J. Mark Heinzle, Alan D. Rendall

We consider models of accelerated cosmological expansion described by the Einstein equations coupled to a nonlinear scalar field with a suitable exponential potential. We show that homogeneous and isotropic solutions are stable under small nonlinear perturbations without any symmetry assumptions. Our proof is based on results on the nonlinear stability of de

David Tegankong, Alan D. Rendall

Global existence results in the past time direction of cosmological models with collisionless matter and a massless scalar field are presented. It is shown that the singularity is crushing and that the Kretschmann scalar diverges uniformly as the singularity is approached. In the case without Vlasov matter, the singularity is velocity dominated and the gener

Pierre Martinetti

We give a brief account of the description of the standard model in noncommutative geometry as well as the thermal time hypothesis, questioning their relevance for quantum gravity.

Aneta Zwierko, Zbigniew Kotulski

The recent developments in the mobile technology (mobile phones, middleware) created a need for new methods of protecting the code transmitted through the network. The proposed mechanisms not only secure the compiled program, but also the data, that can be gathered during its "journey". The oldest and the simplest methods are more concentrated on int

Patrick Haffner, Steven Phillips, Rob Schapire

This paper discusses the application of L1-regularized maximum entropy modeling or SL1-Max [9] to multiclass categorization problems. A new modification to the SL1-Max fast sequential learning algorithm is proposed to handle conditional distributions. Furthermore, unlike most previous studies, the present research goes beyond a single type of conditional dis

Jiri Sima, Satu Elisa Schaeffer

Graph clustering is the problem of identifying sparsely connected dense subgraphs (clusters) in a given graph. Proposed clustering algorithms usually optimize various fitness functions that measure the quality of a cluster within the graph. Examples of such cluster measures include the conductance, the local and relative densities, and single cluster editing

M. J. Holcomb

We have fabricated a series of ex situ copper sheathed powder-in-tube MgB2 wires with 20% by volume Ag, Pb, In, and Ga metal added to the MgB2 powder. We find the transport critical current of these wires increases significantly with the addition of specific metals to the core filament. In particular, the critical current density (Jc) of the MgB2/Ga(20%) wir

Albert C. Pan

We study dynamical heterogeneity and glassy dynamics in a kinetically constrained lattice gas model which has both translational and rotational degrees of freedom. We find that the rotational diffusion constant tracks the structural relaxation time as density is increased whereas the translational diffusion constant exhibits a strong decoupling. We investiga

Oswaldo Dieguez, Karin M. Rabe, David Vanderbilt

Using an extension of a first-principles method developed by King-Smith and Vanderbilt [Phys. Rev. B {\bf 49}, 5828 (1994)], we investigate the effects of in-plane epitaxial strain on the ground-state structure and polarization of eight perovskite oxides: BaTiO$_3$, SrTiO$_3$, CaTiO$_3$, KNbO$_3$, NaNbO$_3$, PbTiO$_3$, PbZrO$_3$, and BaZrO$_3$. In addition,

Vasili Perebeinos, J. Tersoff, Phaedon Avouris

We calculate the radiative lifetime and energy bandstructure of excitons in semiconducting carbon nanotubes, within a tight-binding approach. In the limit of rapid interband thermalization, the radiative decay rate is maximized at intermediate temperatures, decreasing at low temperature because the lowest-energy excitons are optically forbidden. The intrinsi

A. T. Zayak, P. Entel, K. M. Rabe, W. A. Adeagbo

First-principles calculations are used in order to investigate phonon anomalies in non-magnetic and magnetic Heusler alloys. Phonon dispersions for several systems in their cubic L2$\mathrm{_1}$ structure were obtained along the [110] direction. We consider compounds which exhibit phonon instabilities and compare them with their stable counterparts. The anal

Ting-Pong Choy, Philip Phillips

We demonstrate that a Mott insulator lightly doped with holes is still an insulator at low temperature even without disorder. Hole localization obtains because the chemical potential lies in a pseudogap which has a vanishing density of states at zero temperature. The energy scale for the pseudogap is set by the nearest-neighbour singlet-triplet splitting. As

H. Q. Yuan, D. Vandervelde, M. B. Salamon, P. Badica

In this paper we present a penetration depth study on the newly discovered superconductors Li$_2$Pd$_3$B and Li$_2$Pt$_3$B. Surprisingly, the low-temperature penetration depth $f(T)$ demonstrates distinct behavior in these two isostructural compounds. In Li$_2$Pd$_3$B, $f(T)$ follows an exponential decay and can be nicely fitted by a two-gap BCS superconduct

T. R. Kirkpatrick, D. Belitz

The Goldstone mode in the ordered phase of itinerant helimagnets, such as MnSi or FeGe, is determined and shown to have a strongly anisotropic dispersion relation. The softness of this mode is, in a well-defined sense, in between that of ferromagnetic and antiferromagnetic magnons, respectively. It is shown that this soft mode leads to nonanalytic correction

Andrea Montanari, Tommaso Rizzo

We introduce a method for computing corrections to Bethe approximation for spin models on arbitrary lattices. Unlike cluster variational methods, the new approach takes into account fluctuations on all length scales. The derivation of the leading correction is explained and applied to two simple examples: the ferromagnetic Ising model on d-dimensional lattic

Susana Gabbanelli, German Drazer, Joel Koplik

We study an ad hoc extension of the Lattice-Boltzmann method that allows the simulation of non-Newtonian fluids described by generalized Newtonian models. We extensively test the accuracy of the method for the case of shear-thinning and shear-thickening truncated power-law fluids in the parallel plate geometry, and show that the relative error compared to an

Gilson Carneiro

\\A simple model for a superconductor with tunable critical current is studied theoretically. The model consists of a thin superconducting film with one vortex interacting with one magnetic dipole, whose magnetic moment is free to rotate, in the presence of a magnetic field applied parallel to the film surfaces. The pinning potential for the vortex is calcul

Alain Audouard, David Vignolles, Evert Haanappel, Ilya Sheikin

The FS of (ET)8Hg4Cl12(C6H5Br)2 can be regarded as a 2D network of compensated electron and hole orbits coupled by magnetic breakthrough. Simultaneous measurements of the interlayer magnetoresistance and magnetic torque have been performed up to 28 T. Magnetoresistance and de dHvA oscillations spectra exhibit frequency combinations typical of such a network.

S. V. Novikov, G. G. Malliaras

The amplitude of the roughness-induced energetic disorder at the metal/organic interface is calculated. It was found that for moderately rough electrodes, the correction to the electrostatic image potential at the charge location is small. For this reason, roughness-induced energetic disorder cannot noticeably affect charge carrier injection, contrary to the

S. V. Novikov, G. G. Malliaras

The physics of organic semiconductors is dominated by the effects of energetic disorder. We show that image forces reduce the electrostatic component of the total energetic disorder near an interface with a metal electrode. Typically, the variance of energetic disorder is dramatically reduced at the first few layers of organic semiconductor molecules adjacen

Nigel B. Wilding, Peter Sollich, Moreno Fasolo

We study the liquid-vapor phase behaviour of a polydisperse fluid using grand canonical simulations and moment free energy calculations. The strongly nonlinear variation of the fractional volume of liquid across the coexistence region prevents naive extrapolation to detect the cloud point. We describe a finite-size scaling method which nevertheless permits a

Luigi Genovese, David Taj, Fausto Rossi

We shall revisit the conventional treatment of open quantum devices based on the Wigner-Function formalism. Our analysis will show that the artificial spatial separation between device active region and external reservoirs -properly defined within a semiclassical simulation scheme- is intrinsically incompatible with the non-local character of quantum mechani

G. Grabecki, J. Wrobel, T. Dietl, E. Janik

Conductance quantization was measured in submicron constrictions of PbTe, patterned into narrow,12 nm wide quantum wells deposited between Pb$_{0.92}$Eu$_{0.08}$Te barriers. Because the quantum confinement imposed by the barriers is much stronger than the lateral one, the one-dimensional electron energy level structure is very similar to that usually met in

M. Beck, E. Goldobin, M. Neuhaus, M. Siegel

We investigate experimentally a Josephson vortex ratchet -- a fluxon in an asymmetric periodic potential driven by a deterministic force with zero time average. The highly asymmetric periodic potential is created in an underdamped annular long Josephson junction by means of a current injector providing efficiency of the device up to 91%. We measured the ratc

Yoshihiko Ihara, Kenji Ishida, Kazuyoshi Yoshimura, Kazunori Takada

An $^{17}$O NMR measurement was performed on nonoriented polycrystalline Na$_{0.35}$CoO$_2 \cdot y$H$_2$O with superconducting (SC) transition temperature $T_\text{c} = 4.6$ K. A weak temperature dependence was observed in the Knight shift at the O site ($^{17}K$). The spin part of $^{17}K$ ($^{17}K_{\rm spin}$) is estimated from the plot of $^{17}K$ against

I. Pallecchi, C. Tarantini, H. U. Aebersold, V. Braccini

We study the effect of neutron irradiation on the critical current density Jc of isotopically pure polycrystalline Mg11B2 samples. For fluences in the range 1017-1018 cm-2, Jc is enhanced and its dependence on magnetic field is significantly improved: we demonstrate that, in this regime, point-like pinning centers are effectively introduced in the system pro

J. H. Wei, L. X. Wang, K. S. Chan, YiJing Yan

With the Su-Schrieffer-Heeger model involving the effects of solvent polarization and external electric field, we show that bipolaron maybe more stable than two polarons when a dication induced into a DNA stack. Under the high electric field, the dication can move quite a long distance through the DNA by a series of hopping process, partially losing its conf

Matthew Stapleton, Kim Christensen

A general n-state directed `sandpile&#39; model is introduced. The stationary properties of the n-state model are derived for n < infty, and analytical arguments based on a central limit theorem show that the model belongs to the universality class of the totally asymmetric Oslo model, with a crossover to uncorrelated branching process behavior for small sys

W. A. Adeagbo, P. Entel

The Born effective charges of component atoms and phonon spectra of a tetrahedrally coordinated crystalline ice are calculated from the first principles method based on density functional theory within the generalized gradient approximation with the projected augmented wave method. Phonon dispersion relations in a 3x1x1 supercell were evaluated from Hellmann

Yariv Kafri, David R. Nelson, Anatoli Polkovnikov

With magnetic force microscopy in mind, we study the unbinding transition of individual flux lines from extended defects like columnar pins and twin planes in type II superconductors. In the presence of point disorder, the transition is universal with an exponent which depends only on the dimensionality of the extended defect. We also consider the unbinding

W. Vincent Liu

I analyze an atomic Fermi gas with a planar p-wave interaction, motivated by the experimentally observed anisotropy in p-wave Feshbach resonances. An axial superfluid state is verified. A domain wall object is discovered to be a new topological defect of this superfluid and an explicit solution has been found. Gapless quasiparticles appear as bound states on

Andreas Brzank, Gunter Schuetz

We investigate the conditions for reactivity enhancement of catalytic processes in porous solids by use of molecular traffic control (MTC) as a function of reaction rate and grain size. With dynamic Monte-Carlo simulations and continuous-time random walk theory applied to the low concentration regime we obtain a quantitative description of the MTC effect for

W. F. Wreszinski, M. A. da Silva

We revisit an inequality due to Onsager, which states that the (quantum) liquid structure factor has an upper bound of the form (const.) x |k|, for not too large modulus of the wave vector k. This inequality implies the validity of the Landau criterion in the theory of superfluidity with a definite, nonzero critical velocity. We prove an auxiliary propositio

I. Ramirez, C. Allende Prieto, D. L. Lambert

Oxygen abundances for a large sample of dwarf and giant stars kinematically selected to be part of the Galactic thin and thick disks have been determined from a non-LTE analysis of the O I triplet lines at 777 nm. The abundance analysis was performed using the infrared flux method temperature scale, trigonometric surface gravities, and accurate atomic data.

J. R. Stauffer, L. Rebull, J. Carpenter, L. Hillenbrand

Fluxes and upper limits in the wavelength range from 3.6 to 70 microns from the Spitzer Space Telescope are provided for twenty solar-mass Pleiades members. One of these stars shows a probable mid-IR excess and two others have possible excesses, presumably due to circumstellar debris disks. For the star with the largest, most secure excess flux at MIPS wavel

L. Vlahos, C. G. Tsagas, D. Papadopoulos

We study the linear magneto-hydrodynamical behaviour of a Newtonian cosmology with a viscous magnetized fluid of finite conductivity and generalise the Jeans instability criterion. The presence of the field favors the anisotropic collapse of the fluid, which in turn leads to further magnetic amplification and to an enhanced current-sheet formation in the pla

The Fuorescence in Air from Showers, Collaboration

In a test experiment at the Final Focus Test Beam of the Stanford Linear Accelerator Center, the fluorescence yield of 28.5 GeV electrons in air and nitrogen was measured. The measured photon yields between 300 and 400 nm at 1 atm and 29 deg C are Y(760 Torr, air) = 4.42 +/- 0.73 and Y(760 Torr, nitrogen) = 29.2 +/- 4.8 photons per electron per meter. Assumi

J. L. Marshall, Christopher J. Burke, D. L. DePoy, Andrew Gould

We present metallicity estimates for seven open clusters based on spectrophotometric indices from moderate-resolution spectroscopy. Observations of field giants of known metallicity provide a correlation between the spectroscopic indices and the metallicity of open cluster giants. We use χ^2 analysis to fit the relation of spectrophotometric indices to metal

A. Mahdavi, N. Trentham, R. B. Tully

We conduct a photometric and spectroscopic survey of a 10 sq. deg. region surrounding the nearby NGC 5846 group of galaxies, using the Canada-France-Hawaii and Keck I telescopes to study the population of dwarf galaxies as faint as M_R=-10. Candidates are identified on the basis of quantitative surface brightness and qualitative morphological criteria. Spect

S. D. Doty, R. A. Metzler, M. L. Palotti

We present a study of radiative transfer in dusty, clumpy star-forming regions. A series of self-consistent, 3-D, continuum radiative transfer models are constructed for a grid of models parameterized by central luminosity, filling factor, clump radius, and face-averaged optical depth. The temperature distribution within the clouds is studied as a function o

Gustavo E. Romero, Hugo R. Christiansen, Mariana Orellana

We present a hadronic model for gamma-ray production in the microquasar LS I $+61 303$. The system is formed by a neutron star that accretes matter from the dense and slow equatorial wind of the Be primary star. We calculate the gamma-ray emission originated in $pp$ interactions between relativistic protons in the jet and cold protons from the wind. After ta

John P. Subasavage, Todd J. Henry, Nigel C. Hambly, Misty A. Brown

We report the discovery of 152 new high proper motion systems (mu >= 0.4&#34;/yr) in the southern sky (Declination = -47 degrees to 00 degrees) brighter than UKST plate R_{59F} =16.5 via our SuperCOSMOS-RECONS (SCR) search. This paper complements Paper XII in The Solar Neighborhood series, which covered the region from Declination = -90 degrees to -47 degree

Alexandre Arbey

In the standard model of cosmology, the present evolution of the Universe is determined by the presence of two components of unknown nature. One of them is referenced as ``dark matter&#39;&#39; to justify the fact that it behaves cosmologically like usual baryonic matter, whereas the other one is called ``dark energy&#39;&#39;, which is a component with a ne

Maria Massi

The Astrophysics of microquasars - galactic miniatures of the far distant quasars - has become one of the most active fields of modern Astronomy in recent years. Here I review the astronomical methods used for the investigation of these objects, from Gamma-rays over X-rays and optical to radio wavelengths. The description of each astronomical method is alway

Scott F. Anderson, Daryl Haggard, Lee Homer, Nikhil R. Joshi

AM CVn systems are a rare (about a dozen previously known) class of cataclysmic variables, arguably encompassing the shortest orbital periods (down to about 10 minutes) of any known binaries. Both binary components are thought to be degenerate (or partially so), likely with mass-transfer from a helium-rich donor onto a white dwarf, driven by gravitational ra

P. C. Schmidtke, A. P. Cowley

Analysis of the longterm photometric variability of 7 Be/X-ray-pulsar systems in the Small Magellanic Cloud has been carried out. We find a variety of types of variability are present, including: longterm irregular changes, periodic orbital outbursts due to interaction between the stars (weeks to months), low-amplitude quasi-periodic variations of the equato

Janet E. Drew, R. Greimel, M. J. Irwin, IPHAS collaboration

The INT Photometric Halpha Survey of the Northern Galactic Plane (IPHAS) is a 1800 square degrees CCD survey of the northern Milky Way spanning the latitude range -5 < b < +5 (degrees) and reaching down to r&#39; ~ 20 (10-sigma). It may increase the number of known northern emission line sources by an order of magnitude. Representative observations and an as

K. A. Pounds, B. J. Wilkes, K. L. Page

We report on the analysis of a short XMM-Newton observation of the reddened Type 1 QSO 2MASS 234449+1221 first identified in the Two Micron All-Sky Survey. The underlying X-ray continuum is found to be typical of a broad-line active galaxy, with photon index Gamma ~ 1.9. Low energy absorption can be modelled by a column N_H ~ 10^22 cm^{-2} of moderately ioni

S. J. O&#39;Toole, U. Heber, C. S. Jeffery, S. Dreizler

We present results and analysis for the 2m spectroscopic part of the MultiSite Spectroscopic Telescope (MSST) campaign undertaken in May/June 2002. The goal of the project was to observe the pulsating subdwarf B star PG1605+072 simultaneously in velocity and photometry and to resolve as many of the >50 known modes as possible, which will allow a detailed ast

Olivier Mousis, Ulysse Marboeuf, Jean-Marc C. Petit, Jurgen Klinger

Using the cometary nucleus model developed by Espinasse et al. (1991), we calculate the thermodynamical evolution of Comet 9P/Tempel 1 over a period of 360 years. Starting from an initially amorphous cometary nucleus which incorporates an icy mixture of H2O and CO, we show that, at the time of Deep Impact collision, the crater is expected to form at depths w

Frank M. Rieger

We consider the periodic modulation of emission from jets in blazar-type sources. A differential Doppler boosting origin, associated with the helical motion of a radiating component, is analyzed for different periodic driving sources including orbital motion and jet precession in a binary black hole system (BBHS). We emphasize that for non-ballistic helical

Frank M. Rieger, Peter Duffy

We review the acceleration of energetic particles in relativistic astrophysical jets characterized by a significant velocity shear. The possible formation of power-law momentum spectra is discussed and typical acceleration timescales are determined for a variety of different conditions such as parallel and azimuthal shear flows. Special attendance is given t

S. Mateos, X. Barcons, F. J. Carrera, M. T. Ceballos

This paper presents the results of a detailed X-ray spectral analysis of a sample of 123 X-ray sources (46 being type-1 AGN and 28 type-2 AGN) detected with XMM-Newton in the Lockman Hole field. Using a single power law model our sources&#39; average spectral slope hardens at faint 0.5-2 keV fluxes but not at faint 2-10 keV fluxes. We explain the effect in t

Pedro F. Gonzalez-Diaz, Jose A. Jimenez Madrid

This paper deals with a study of the cylindrically symmetric accretion of dark energy with equation of state $p=wρ$ onto wiggly straight cosmic strings. We have obtained that when $w>-1$ the linear energy density in the string core gradually increases tending to a finite maximum value as time increases for all considered dark energy models. On the regime whe

E. Sturm, M. Schweitzer, D. Lutz, A. Contursi

We report the first detection of ~10 and ~18 micron silicate dust emissions in a low-luminosity active galactic nucleus (AGN), obtained in Spitzer-IRS 7-37 micron spectroscopy of the Type 1 LINER galaxy NGC3998. Silicate emissions in AGN have only recently been detected in several quasars. Our detection counters suggestions that silicate emissions are presen

Masayuki Tanaka, Tadayuki Kodama, Nobuo Arimoto, Sadanori Okamura

We discuss the environmental dependence of galaxy evolution based on deep panoramic imaging of two distant clusters taken with Suprime-Cam as part of the PISCES project. By combining with the SDSS data as a local counterpart for comparison, we construct a large sample of galaxies that spans wide ranges in environment, time, and stellar mass (or luminosity).

Hai Fu, Alan Stockton, Michael Liu

We have identified a clustering of red galaxies from deep optical/IR images obtained as part of the Institute for Astronomy Deep Survey. Photometric spectral-energy distributions indicate that most of these galaxies comprise nearly pure old stellar populations at a redshift near 1.4, and Keck spectroscopy of the three brightest red galaxies confirm this inte

Gunn Kim, Yeonju Kim, Jisoon Ihm

We study the energetics of acetylene (${\rm C_2H_2}$) molecules inside a carbon nanotube (CNT) using the {\it ab initio} pseudopotential method. The encapsulation energy of a single ${\rm C_2H_2}$ molecule into the nanotube and the formation energy of ${\rm (C_2H_2)}_n$@CNT are calculated. We investigate whether a polyacetylene chain can be produced by fusio

Puze Gao, Bo-Qiang Ma

We propose a means to detect the nucleon strange quark-antiquark asymmetry, which is predicted as a non-perturbative effect, but still unchecked directly by available experiments. The difference for the $D(c\bar{q})$ and $\bar{D}(\bar{c}q)$ meson production cross sections in neutrino and antineutrino induced charged current deep inelastic scattering is illus

Peter J. Love, Bruce M. Boghosian

We review and analyze the hybrid quantum-classical NMR computing methodology referred to as Type-II quantum computing. We show that all such algorithms considered so far within this paradigm are equivalent to some classical lattice-Boltzmann scheme. We derive a sufficient and necessary constraint on the unitary operator representing the quantum mechanical pa

Michael M. Shara, Sasha Hinkley, David R. Zurek, Christian Knigge

NGC 6397 is the closest globular cluster, and hence the ideal place to search for faint stellar populations such as cataclysmic variables (CVs). HST and Chandra observers have identified nine certain and likely CVs in this nearby cluster, including several magnetic CV candidates. We have combined our recent UV imagery with archival HST images of NGC 6397 to

Rituparno Goswami, Pankaj S. Joshi, Parampreet Singh

We investigate here quantum effects in gravitational collapse of a scalar field model which classically leads to a naked singularity. We show that non-perturbative semi-classical modifications near the singularity, based on loop quantum gravity, give rise to a strong outward flux of energy. This leads to the dissolution of the collapsing cloud before the sin

Carolyn Sealfon, Licia Verde, Raul Jimenez

We reconstruct the shape of the primordial power spectrum (PPS) using a smoothing spline. Our adapted smoothing spline technique provides a complementary method to existing efforts to search for smooth features in the PPS, such as a running spectral index. With this technique we find no significant indication with WMAP first-year data that the PPS deviates f

Ashkan Nikeghbali

This text is a survey of the general theory of stochastic processes, with a view towards random times and enlargements of filtrations. The first five chapters present standard materials, which were developed by the French probability school and which are usually written in French. The material presented in the last three chapters is less standard and takes i

G. I. Rigopoulos, E. P. S. Shellard, B. J. W. van Tent

We investigate non-Gaussianity in general multiple-field inflation using the formalism we developed in earlier papers. We use a perturbative expansion of the non-linear equations to calculate the three-point correlator of the curvature perturbation analytically. We derive a general expression that involves only a time integral over background and linear pert

Kentaro Hori, Kazuo Hosomichi, David C. Page, Raul Rabadan

After orientifold projection, the conifold singularity in hypermultiplet moduli space of Calabi-Yau compactifications cannot be avoided by geometric deformations. We study the non-perturbative fate of this singularity in a local model involving O6-planes and D6-branes wrapping the deformed conifold in Type IIA string theory. We classify possible A-type orien

Dmitri I. Panyushev

The goal of this paper is to extend the standard invariant-theoretic design, well-developed in the reductive case, to the setting of representation of certain non-reductive groups. This concerns the following notions and results: the existence of generic stabilisers and generic isotropy groups for finite-dimensional representations; structure of the fields a

C. Aubin, C. Bernard, C. DeTar, M. Di Pierro

We present the first lattice QCD calculation with realistic sea quark content of the D^+ meson decay constant f_{D^+}. We use the MILC Collaboration&#39;s publicly available ensembles of lattice gauge fields, which have a quark sea with two flavors (up and down) much lighter than a third (strange). We obtain f_{D^+} = 201 +/- 3 +/- 17 MeV, where the errors a

Francesco Costantino, Dylan P. Thurston

It is known since 1954 that every 3-manifold bounds a 4-manifold. Thus, for instance, every 3-manifold has a surgery diagram. There are several proofs of this fact, including constructive proofs, but there has been little attention to the complexity of the 4-manifold produced. Given a 3-manifold M of complexity n, we show how to construct a 4-manifold bounde

S. F. King

We show how the neutrino mixing angles and oscillation phase can be predicted from tri-bimaximal neutrino mixing, corrected by charged lepton mixing angles which are related to quark mixing angles via quark-lepton unification. The tri-bimaximal neutrino mixing can naturally originate from the see-saw mechanism via constrained sequential dominance (CSD), wher

P. Castelo Ferreira

We study electric stationary radial symmetric classical solutions of the U(1) Einstein Maxwell Chern-Simons theory coupled to a gravitational massless scalar field with a cosmological constant in 2+1 dimensions. Generic aspects of the theory are discussed at an introductory level. We study solutions for both negative sign (standard) and positive sign (ghost)

N. Beisert, L. Freyhult

We study fluctuations and finite size corrections for the ferromagnetic thermodynamic limit in the Bethe ansatz for the Heisenberg XXX1/2 spin chain, which is the AdS/CFT dual of semiclassical spinning strings. For this system we derive the standard quantum mechanical formula which expresses the energy shift as a sum over fluctuation energies. As an example

David W. Lyons, Scott N. Walck

The group of local unitary transformations acts on the space of n-qubit pure states, decomposing it into orbits. In a previous paper we proved that a product of singlet states (together with an unentangled qubit for a system with an odd number of qubits) achieves the smallest possible orbit dimension, equal to 3n/2 for n even and (3n + 1)/2 for n odd, where

S. Basak, R. G. Edwards, G. T. Fleming, U. M. Heller

The design and implementation of large sets of spatially-extended, gauge-invariant operators for use in determining the spectrum of baryons in lattice QCD computations are described. Group-theoretical projections onto the irreducible representations of the symmetry group of a cubic spatial lattice are used in all isospin channels. The operators are construct

Cintia M. Lapilli, Carlos Wexler

A variety of recent experiments probing the low-temperature transport properties of quantum Hall systems have suggested an interpretation in terms of liquid crystalline mesophases dubbed {\em quantum Hall liquid crystals}. The single mode approximation (SMA) has been a useful tool for the determination of the excitation spectra of various systems such as pho

S. Grecu, M. Roggenbuck, A. Opitz, W. Bruetting

The influence of substrate treatment with self-assembled monolayers and thermal annealing was analysed by electrical and structural measurements on field-effect transistors (FETs) and metal-insulator-semiconductor (MIS) diodes using poly(3-hexylthiophene) (P3HT) as a semiconducting polymer and Si/SiO2 wafers as a substrate. It is found that surface treatment

Soumik Mukhopadhyay, I. Das

This paper is withdrawn.

Joerg B. Goette, Roberta Zambrini, Sonja Franke-Arnold, Stephen M. Barnett

The equality in the uncertainty principle for linear momentum and position is obtained for states which also minimize the uncertainty product. However, in the uncertainty relation for angular momentum and angular position both sides of the inequality are state dependent and therefore the intelligent states, which satisfy the equality, do not necessarily give

M. Malinsky, J. C. Romao, J. W. F. Valle

We propose a new seesaw mechanism for neutrino masses within a class of supersymmetric SO(10) models with broken D-parity. It is shown that in such scenarios the B-L scale can be as low as TeV without generating inconsistencies with gauge coupling unification nor with the required magnitude of the light neutrino masses. This leads to a possibly light new neu

Janusz Grabowski

It is proven that a local Lie algebra in the sense of A. A. Kirillov determines the base manifold up to a diffeomorphism provided the anchor map is nowhere-vanishing. In particular, the Lie algebras of nowhere-vanishing Poisson or Jacobi brackets determine manifolds. This result has been proven for different types of differentiability: smooth, real-analytic,

A. V. Luchinsky

In this paper the leading twist contribution to $χ_{c0,2}\toωω$ decays in the color singlet approximation is considered. It is shown, that the predictions for $\Br(χ_0\toωω)$ is in a good agreement with the experimental data, while $\Br(χ_{c2}\toωω)$ differs from the experiment significantly.

M. Caselle, U. Magnea

Using an innovative technique arising from the theory of symmetric spaces, we obtain an approximate analytic solution of the Dorokhov-Mello-Pereyra-Kumar (DMPK) equation in the insulating regime of a metallic carbon nanotube with symplectic symmetry and an odd number of conducting channels. This symmetry class is characterized by the presence of a perfectly

Daniel Bulacu, Florin Panaite, Freddy Van Oystaeyen

In this paper we introduce generalizations of diagonal crossed products, two-sided crossed products and two-sided smash products, for a quasi-Hopf algebra H. The results we obtain may be applied to H^*-Hopf bimodules and generalized Yetter-Drinfeld modules. The generality of our situation entails that the &#34;generating matrix&#34; formalism cannot be used,

Doron Gepner

We introduce a Monte--Carlo simulation approach to thermodynamic Bethe ansatz (TBA). We exemplify the method on one particle integrable models, which include a free boson and a free fermions systems along with the scaling Lee--Yang model (SLYM). It is confirmed that the central charges and energies are correct to a very good precision, typically 0.1% or so.

Isao Kishimoto, Tomohiko Takahashi

We construct a class of classical solutions in the Berkovits&#39; open superstring field theory. The resulting solutions correspond to marginal boundary deformations in conformal field theory. The vacuum energy vanishes exactly for the solutions. Investigating the theory expanded around one of the solutions, we find that it reflects the effect of background

Sabine Wurmehl, Gerhard H. Fecher, Hem C. Kandpal, Vadim Ksenofontov

In this work a simple concept was used for a systematic search for new materials with high spin polarization. It is based on two semi-empirical models. Firstly, the Slater-Pauling rule was used for estimation of the magnetic moment. This model is well supported by electronic structure calculations. The second model was found particularly for Co$_2$ based Heu

Monika Ludwig, Matthias Reitzner

It is proved that a triangulation of a polyhedron can always be transformed into any other triangulation of the polyhedron by using only elementary moves. One consequence is that an additive function (valuation) defined only on simplices may always be extended to an additive function on all polyhedra.

Bing Wang, Huanwen Tang, Chonghui Guo, Zhilong Xiu

Many networks are characterized by highly heterogeneous distributions of links, which are called scale-free networks and the degree distributions follow $p(k)\sim ck^{-α}$. We study the robustness of scale-free networks to random failures from the character of their heterogeneity. Entropy of the degree distribution can be an average measure of a network&#39;

A. G. Mal&#39;shukov, L. Y. Wang, C. S. Chu, K. A. Chao

The intrinsic spin-Hall effect on spin accumulation and electric conductance in a diffusive regime of a 2D electron gas has been studied for a 2D strip of a finite width. It is shown that the spin polarization near the flanks of the strip, as well as the electric current in the longitudinal direction exhibit damped oscillations as a function of the width and

S. Moch, J. A. M. Vermaseren, A. Vogt

We extend the threshold resummation exponents G^N in Mellin-N space to the fourth logarithmic (N^3LL) order collecting the terms alpha_s^2 (alpha_s ln N)^n to all orders in the strong coupling constant as. Comparing the results to our previous three-loop calculations for deep-inelastic scattering (DIS), we derive the universal coefficients B_q and B_g govern

Sean A. Hayward

Regular (non-singular) space-times are given which describe the formation of a (locally defined) black hole from an initial vacuum region, its quiescence as a static region, and its subsequent evaporation to a vacuum region. The static region is Bardeen-like, supported by finite density and pressures, vanishing rapidly at large radius and behaving as a cosmo

Li Xiao, Jonathan A. Jones

We describe Nuclear Magnetic Resonance (NMR) demonstrations of the quantum Zeno effect, and discuss briefly how these are related to similar phenomena in more conventional NMR experiments.

Axel Kleinschmidt, Hermann Nicolai

We study the indefinite Kac-Moody algebras AE(n), arising in the reduction of Einstein&#39;s theory from (n+1) space-time dimensions to one (time) dimension, and their distinguished maximal regular subalgebras sl(n) and affine A_{n-2}^{(1)}. The interplay between these two subalgebras is used, for n=3, to determine the commutation relations of the `gradient

Manfred Lindner, Michael Ratz, Michael Andreas Schmidt

There are good reasons why neutrinos could be Majorana particles, but there exist also a number of very good reasons why neutrinos could have Dirac masses. The latter option deserves more attention and we derive therefore analytic expressions describing the renormalization group evolution of mixing angles and of the CP phase for Dirac neutrinos. Radiative co

J. I. Read, M. I. Wilkinson, N. W. Evans, G. Gilmore

We present an improved analytic calculation for the tidal radius of satellites and test our results against N-body simulations. The tidal radius in general depends upon four factors: the potential of the host galaxy, the potential of the satellite, the orbit of the satellite and {\it the orbit of the star within the satellite}. We demonstrate that this last

A. Erbas, A. Tuncer, B. Yucesoy, A. N. Berker

Hierarchical lattices that constitute spatially anisotropic systems are introduced. These lattices provide exact solutions for hierarchical models and, simultaneously, approximate solutions for uniaxially or fully anisotropic d=3 physical models. The global phase diagrams, with d=2 and d=1 to d=3 crossovers, are obtained for Ising, XY magnetic models and per

A. L. Alexander, J. J. Longdell, M. J. Sellars, N. B. Manson

We demonstrate photon echoes in Eu$^{3+}$:Y$_{2}$SiO$_{5}$ by controlling the inhomogeneous broadening of the Eu$^{3+}$ $^{7}$F$_{0}\leftrightarrow^{5}$D$_{0}$ optical transition. This transition has a linear Stark shift and we induce inhomogeneous broadening by applying an external electric field gradient. After optical excitation, reversing the polarity of

Jing-Ling Chen, Chunfeng Wu, L. C. Kwek, C. H. Oh

We present tight Bell inequalities expressed by probabilities for three four- and five-dimensional systems. The tight structure of Bell inequalities for three $d$-dimensional systems (qudits) is proposed. Some interesting Bell inequalities of three qubits reduced from those of three qudits are also studied.

W. Struyve

In this thesis we study the de Broglie-Bohm pilot-wave interpretation of quantum theory. We consider the domain of non-relativistic quantum theory, relativistic quantum theory and quantum field theory, and in each domain we consider the possibility of formulating a pilot-wave interpretation. For non-relativistic quantum theory a pilot-wave interpretation in