April 2008 arXiv papers — page 24

Akira Masuoka

By using cocycle deformation, we construct a certain class of Hopf algebras, containing the quantized enveloping algebras and their analogues, from what we call pre-Nichols algebras. Our construction generalizes in some sense the known construction by (generalized) quantum doubles, but unlike in the known situation, it saves us from difficulties in checking

Gang Liu, Jairo Valesco, Wenzhong Bao, Chun Ning Lau

We developed a multi-level lithography process to fabricate graphene p-n-p junctions with the novel geometry of contactless, suspended top gates. This fabrication procedure minimizes damage or doping to the single atomic layer, which is only exposed to conventional resists and developers. The process does not require special equipment for depositing gate die

Nicola Garofalo, Arshak Petrosyan

We construct two new one-parameter families of monotonicity formulas to study the free boundary points in the lower dimensional obstacle problem. The first one is a family of Weiss type formulas geared for points of any given homogeneity and the second one is a family of Monneau type formulas suited for the study of singular points. We show the uniqueness an

Gregory M. Crosswhite, Andrew C. Doherty, Guifre Vidal

An algorithm is presented which computes a translationally invariant matrix product state approximation of the ground state of an infinite 1D system; it does this by embedding sites into an approximation of the infinite ``environment'' of the chain, allowing the sites to relax, and then merging them with the environment in order to refine the approxi

Michael J. W. Hall

A recent proposal for mixed dynamics of classical and quantum ensembles is shown, in contrast to other proposals, to satisfy the minimal algebraic requirements proposed by Salcedo for any consistent formulation of such dynamics. Generalised Ehrenfest relations for the expectation values of classical and quantum observables are also obtained. It is further sh

Mario Berberan-Santos

A simple relaxation function I(t/tauzero; alpha, beta) unifying the stretched exponential with the compressed hyperbola is obtained, and its properties studied. The scaling parameter tauzero has dimensions of time, whereas the shape-determining parameters alpha and beta are dimensionless, both taking values between 0 and 1. For short times, the relaxation fu

Alan Rufty

A reproducing kernel Hilbert space (RKHS) has four well-known easily derived properties. Since these properties are usually not emphasized as a simple means of gaining insight into RKHS structure, they are singled out and proved in this brief article.

Ian Christopher, Dennis Huo, Bryan Jacobs

This paper refutes the validity of the polynomial-time algorithm for solving satisfiability proposed by Sergey Gubin. Gubin introduces the algorithm using 3-SAT and eventually expands it to accept a broad range of forms of the Boolean satisfiability problem. Because 3-SAT is NP-complete, the algorithm would have implied P = NP, had it been correct. Additiona

Richard Atkins

We consider the more general question as to when a connection is a metric connection. There are two aspects to this investigation: first, the determination of the integrability conditions that ensure the existence of a local parallel metric in the neighbourhood of a given point and second, the characterization of the topological obstruction to a globally def

R. Gueven

We show that the conformal Penrose limit is an ordinary plane wave limit in a higher dimensional framework which resolves the spacetime singularity. The higher dimensional framework is provided by Ricci-flat manifolds which are of the form M_D = M_d x B, where M_d is an Einstein spacetime that has a negative cosmological constant and admits a spacelike confo

A. Asensio Ramos, J. Trujillo Bueno, E. Landi Degl'Innocenti

A big challenge in solar and stellar physics in the coming years will be to decipher the magnetism of the solar outer atmosphere (chromosphere and corona) along with its dynamic coupling with the magnetic fields of the underlying photosphere. To this end, it is important to develop rigorous diagnostic tools for the physical interpretation of spectropolarimet

Goren Gordon, Gershon Kurizki, Daniel A. Lidar

A theory of dynamical control by modulation for optimal decoherence reduction is developed. It is based on the non-Markovian Euler-Lagrange equation for the energy-constrained field that minimizes the average dephasing rate of a qubit for any given dephasing spectrum.

Louiza Fouli, Claudia Polini, Bernd Ulrich

We prove formulas for the core of ideals that apply in arbitrary characteristic.

Francisco M. Fernandez

We obtain tight upper and lower bounds to the eigenvalues of an anharmonic oscillator with a rational potential. We compare our bounds with results given by other approaches.

Tom Banks, Linda M. Carpenter, Jean-François Fortin

We discuss SUSY models in which renormalizable lepton number violating couplings hide the decay of the Higgs through h -> χ_1^0 + χ_1^0 followed by χ_1^0 -> τ+ 2 jets or χ_1^0 -> ν_τ+ 2 jets and also explain neutrino masses. This mechanism can be made compatible with gauge mediated SUSY breaking.

Gisana C. A. Bueno, W. B. Cardoso, A. T. Avelar, B. Baseia

We propose a scheme to generate arbitrary Fock states |N> in a cavity QED using N resonant Rydberg atoms. The atom-field interaction times are controlled via Stark-shifts adjusted in a way that each atom transfers a photon to the cavity, turning atomic detections useless. Fluctuations affecting the control of the atom-field interactions are also considered.

P. R. Silva

In this paper we examine the connection among the themes: the cosmological constant, the weak interaction and the neutrino mass. Our main propose is to review and modify the ideas first proposed by Hayakawa [ Prog. Theor. Phys.Suppl.,532(1965).], in the light of the new-fashioned features of contemporary physics. Assuming the pressure of a Fermi gas of neutr

Shari Moskow, John C. Schotland

We analyze the inverse scattering series for diffuse waves in random media. In previous work the inverse series was used to develop fast, direct image reconstruction algorithms in optical tomography. Here we characterize the convergence, stability and approximation error of the series

M. E. Dieckmann, A. Meli, P. K. Shukla, L. O. C. Drury

Supernova remnant (SNR) blast shells can reach the flow speed $v_s = 0.1 c$ and shocks form at its front. Instabilities driven by shock-reflected ion beams heat the plasma in the foreshock, which may inject particles into diffusive acceleration. The ion beams can have the speed $v_b \approx v_s$. For $v_b \ll v_s$ the Buneman or upper-hybrid instabilities do

Heron Caldas, Jean-Loic Kneur, Marcus B. Pinto, Rudnei O. Ramos

The Optimized Perturbation Theory (OPT) method, at finite temperature and finite chemical potential, is applied to the field theory model for polyacetylene. The critical dopant concentration in trans-polyacetylene is evaluated and compared with the available experimental data and with previous calculations. The results obtained within the OPT go beyond the s

G. T. van Belle

Planet transit events present as attractive targets for the ultra-high-resolution capabilities afforded by optical interferometers. Herein is presented an evaluation of the possibility of detection of such events through measurement of high-precision closure phases with the MIRC instrument on the CHARA Array. Recovery of the transit position angle upon the s

S. Komossa, H. Zhou, T. Wang, M. Ajello

We report the discovery of superstrong, fading, high-ionization iron line emission in the galaxy SDSSJ095209.56+214313.3 (SDSSJ0952+2143 hereafter), which must have been caused by an X-ray outburst of large amplitude. SDSSJ0952+2143 is unique in its strong multiwavelength variability; such a broadband emission-line and continuum response has not been observe

G. E. Murgida, D. A. Wisniacki, P. I. Tamborenea

We study the transitions between neighboring energy levels in a quasi-one-dimensional semiconductor quantum dot with two interacting electrons in it, when it is subject to a linearly time-dependent electric field. We analyze the applicability of simple two-level Landau-Zener model to describe the evolution of the probability amplitudes in this realistic syst

Jeffrey C. Y. Teo, Liang Fu, C. L. Kane

We study the electronic surface states of the semiconducting alloy BiSb. Using a phenomenological tight binding model we show that the Fermi surface of the 111 surface states encloses an odd number of time reversal invariant momenta (TRIM) in the surface Brillouin zone confirming that the alloy is a strong topological insulator. We then develop general argum

Peter D. Horn

We consider the Grope filtration of the classical knot concordance group that was introduced in a paper of Cochran, Orr and Teichner. Our main result is that successive quotients at each stage in this filtration have infinite rank. We also establish the analogous result for the Grope filtration of the concordance group of string links consisting of more than

Juergen Horbach

The structural and dynamic properties of silica melts under high pressure are studied using molecular dynamics (MD) computer simulation. The interactions between the ions are modeled by a pairwise-additive potential, the so-called CHIK potential, that has been recently proposed by Carre et al. The experimental equation of state is well-reproduced by the CHIK

W. Muschik, H. -H. v. Borzeszkowski

On the basis of the balance equations for energy-momentum, spin, particle and entropy density, an approach is considered which represents a comparatively general framework for special- and general-relativistic continuum thermodynamics. In the first part of the paper, a general entropy density 4-vector, containing particle, energy-momentum, and spin density c

Kurt Binder, Juergen Horbach, Richard Vink, Andres De Virgiliis

When systems that can undergo phase separation between two coexisting phases in the bulk are confined in thin film geometry between parallel walls, the phase behavior can be profoundly modified. These phenomena shall be described and exemplified by computer simulations of the Asakura-Oosawa model for colloid-polymer mixtures, but applications to other soft m

Jan Reimann

We show that if a real $x$ is strongly Hausdorff $h$-random, where $h$ is a dimension function corresponding to a convex order, then it is also random for a continuous probability measure $μ$ such that the $μ$-measure of the basic open cylinders shrinks according to $h$. The proof uses a new method to construct measures, based on effective (partial) continuo

Natalia Babych

We consider an elastic system containing a small region where the density is very much higher then elsewhere. Such system possesses two types of eigenvibrations, which are local and global vibrations. Complete asymptotic expansions of global eigenvibrations for ordinary differential operator of the fourth order are constructed using WKB--technique.

Michael Hawlitzky, Juergen Horbach, Simona Ispas, Matthias Krack

A Molecular Dynamics (MD) study of static and dynamic properties of molten and glassy germanium dioxide is presented. The interactions between the atoms are modelled by the classical pair potential proposed by Oeffner and Elliott (OE) [Oeffner R D and Elliott S R 1998, Phys. Rev. B, 58, 14791]. We compare our results to experiments and previous simulations.

Baris I. Erkmen, Jeffrey H. Shapiro

Biphoton states of signal and idler fields--obtained from spontaneous parametric downconversion (SPDC) in the low-brightness, low-flux regime--have been utilized in several quantum imaging configurations to exceed the resolution performance of conventional imagers that employ coherent-state or thermal light. Recent work--using the full Gaussian-state descrip

J. I. Aranda, F. Ramírez--Zavaleta, J. J. Toscano, E. S. Tututi

The size of the branching ratios for the $τ\to μγ$ and $τ\to μγγ$ decays induced by a lepton flavor violating Higgs interaction $Hτμ$ is studied in the frame of effective field theories. The best constraint on the $Hτμ$ vertex, derived from the know measurement on the muon anomalous magnetic moment, is used to impose the upper bounds $Br(τ\to μγ)<2.5\times 1

Paolo Gibilisco, Tommaso Isola

Recently Kosaki proved an inequality for matrices that can be seen as a kind of new uncertainty principle. Independently, the same result was proved by Yanagi, Furuichi and Kuriyama. The new bound is given in terms of Wigner-Yanase-Dyson informations. Kosaki himself asked if this inequality can be proved in the setting of von Neumann algebras. In this paper

Paolo Gibilisco, Tommaso Isola

Recently Kosaki proved an uncertainty principle for matrices, related to Wigner-Yanase-Dyson information, and asked if a similar inequality could be proved in the von Neumann algebra setting. In this paper we prove such an uncertainty principle in the semifinite case.

A. Widom, Y. N. Srivastava, L. Larsen

Collective Ampere law interactions producing magnetic flux tubes piercing through sunspots into and then out of the solar corona allow for low energy nuclear reactions in a steady state and high energy particle reactions if a magnetic flux tube explodes in a violent event such as a solar flare. Filamentous flux tubes themselves are vortices of Ampere current

I. K. Kominis

The intricate biochemical processes underlying avian magnetoreception, the sensory ability of migratory birds to navigate using earths magnetic field, have been narrowed down to spin-dependent recombination of radical-ion pairs to be found in avian species retinal proteins. The avian magnetic field detection is governed by the interplay between magnetic inte

Christian Daveau, Abdessatar Khelifi, Anton Sushchenko

In this paper we determine a formula for calculating the refractive index ${\bf n}$ for the acoustic equation from the partial Dirichlet to Neumann map(DN) associated to ${\bf n}$. We apply these results to identify locations and values of small volume perturbations of this refractive index at fixed frequency $ω$.

R. Garcia-Martin, R. Kaminski, J. R. Pelaez

We review how the use of recent precise data on kaon decays together with forward dispersion relations (FDR) and Roy&#39;s equations allow us to determine the sigma resonance pole position very precisely, by using only experimental input. In addition, we present preliminary results for a modified set of Roy-like equations with only one subtraction, that show

Pedro Miranda, Michel Grabisch, Pedro Gil

In this paper we propose a generalization of the concept of symmetric fuzzy measure based in a decomposition of the universal set in what we have called subsets of indifference. Some properties of these measures are studied, as well as their Choquet integral. Finally, a degree of interaction between the subsets of indifference is defined.

Marta Lewicka, Maria Giovanna Mora, Mohammad Reza Pakzad

We study the $Γ$-limit of 3d nonlinear elasticity for shells of small, variable thickness, around an arbitrary smooth 2d surface.

Giorgio Giardina, Giovanni Fazio, Giuseppe Mandaglio, Marina Manganaro

We obtained the spectrum of probability of the bremsstrahlung emission accompanying the $α$-decay of $^{226}{\rm Ra}$ (E$_α$=4.8 MeV) by measuring the $α$-$γ$ coincidences and using the model presented in our previous study on the $α-$decay of $^{214}{\rm Po}$ (E$_α$=7.7 MeV). We compare the experimental data with the quantum mechanical calculation and find

R. Combescot, S. Giraud

We consider a single \down atom within a Fermi sea of \up atoms. We elucidate by a full many-body analysis the quite mysterious agreement between Monte-Carlo results and approximate calculations taking only into account single particle-hole excitations. It results from a nearly perfect destructive interference of the contributions of states with more than on

C Sivaram, Kenath Arun, Venkata Manohara Reddy A

Matter collapsing to a singularity in a gravitational field is still an intriguing question. Similar situation arises when discussing the very early universe or a universe recollapsing to a singularity. It is suggested that inclusion of mutual gravitational interactions among the collapsing particles can avert a singularity and give finite value for various

Chao Jiang

The site preference of 3d (Ti-Cu), 4d (Zr-Ag) and 5d (Hf-Au) transition-metal elements in L10 TiAl is studied using a combination of first-principles supercell calculations and the statistical mechanical Wagner-Schottky model. Our key finding is that both temperature and alloy stoichiometry can strongly affect the site occupancy behavior of ternary alloying

S. Lafèbre, H. Falcke, J. Hörandel, J. Kuijpers

The Solar radiation field may break apart ultra high energy cosmic nuclei, after which both remnants will be deflected in the interplanetary magnetic field in different ways. This process is known as the Gerasimova-Zatsepin effect after its discoverers. We investigate the possibility of using the detection of the separated air showers produced by a pair of r

J. R. Pelaez, R. Garcia-Martin, R. Kaminski, F. J. Yndurain

We review our recent analysis of pion-pion scattering data in terms of Roy equations and Forward Dispersion Relations, and present some preliminary results in terms of a new set of once-subtracted coupled equations for partial waves. The first analysis consists of independent fits to the different pion-pion channels that satisfies rather well the dispersive

Michael J. Mortonson, Wayne Hu

We study the constraints on reionization from five years of WMAP data, parametrizing the evolution of the average fraction of ionized hydrogen with principal components that provide a complete basis for describing the effects of reionization on large-scale E-mode polarization. Using Markov Chain Monte Carlo methods, we find that the resulting model-independe

Francois Gelis, Tuomas Lappi, Raju Venugopalan

We derive a high energy factorization theorem for inclusive gluon production in A+A collisions. Our factorized formula resums i) all order leading logarithms (g^2 \ln(1/x_{1,2}))^n of the incoming partons momentum fractions, and ii) all contributions (g ρ_{1,2})^n that are enhanced when the color charge densities in the two nuclei are of order of the inverse

Rolf Walder, Doris Folini, Steven N. Shore

RS Ophiuchi is a recurrent nova with a period of about 22 years, consisting of a wind accreting binary system with a white dwarf (WD) very close to the Chandrasekhar limit and a red giant star (RG). The system is considered a prime candidate to evolve into an SNIa. We present a 3D hydrodynamic simulation of the quiescent accretion and the subsequent explosiv

Johan Engquist, Olaf Hohm

We review the construction of consistent higher-spin theories based on Chern-Simons actions. To this end we first introduce the required higher-spin algebras and discuss curvature and torsion tensors in an unconstrained way. Finally we perform a perturbative analysis of the Chern-Simons theory in D=5 for a non-maximally symmetric AdS(4) background and obtain

L. Hozoi, U. Birkenheuer, H. Stoll, P. Fulde

A fully ab initio scheme based on quantum chemical wavefunction methods is used to investigate the correlated multiorbital electronic structure of a 3d-metal compound, LaCoO3. The strong short-range electron correlations, involving both Co and O orbitals, are treated by multireference techniques. The use of effective parameters like the Hubbard U and interor

Amy Cassidy, Ilya Grigorenko, Stephan Haas

We investigate theoretically the formation of collective excitations in atomic scale quasi-one dimensional metallic nanostructures. The response of the system is calculated within the linear response theory and random phase approximation. For uniform nanostructures a transition from quantum single particle excitations to classical plasmon scaling is observed

Abhay N. Pasupathy, Aakash Pushp, Kenjiro K. Gomes, Colin V. Parker

Identifying the mechanism of superconductivity in the high-temperature cuprate superconductors is one of the major outstanding problems in physics. We report local measurements of the onset of superconducting pairing in the high-transition temperature (Tc) superconductor Bi2Sr2CaCu2O8+d using a lattice-tracking spectroscopy technique with a scanning tunnelin

Christoph Schommer

This Master of Science in Computer and Information Sciences (MICS) is an international accredited master program that has been initiated in 2004 and started in September 2005. MICS is a research-oriented academic study of 4 semesters and a continuation of the Bachelor towards the PhD. It is completely taught in English, supported by lecturers coming from mor

Mauricio Martinez, Michael Strickland

We discuss dilepton production from a quark-gluon plasma which has a time-dependent anisotropy in momentum space. A phenomenological model for the hard momentum scale, p_hard(tau) and the plasma anisotropy parameter, xi(tau), is presented. The model interpolates between early-time 1+1 free streaming behavior (tau << tau_iso) and late-time ideal 1+1 hydrodyna

B. Nikolic, B. Sazdovic

We choose such boundary conditions for open IIB superstring theory which preserve N=1 SUSY. The explicite solution of the boundary conditions yields effective theory which is symmetric under world-sheet parity transformation $Ω:σ\to-σ$. We recognize effective theory as closed type I superstring theory. Its background fields,beside known $Ω$ even fields of th

Mohsen Shadmehri, Turlough P. Downes

We investigate the linear theory of Kelvin-Helmholtz instability at the interface between a partially ionized dusty outflow and the ambient material analytically. We model the interaction as a multifluid system in a planar geometry. The unstable modes are independent from the charge polarity of the dust particles. Although our results show a stabilizing effe

Laura Anna Ripamonti, Ines Di Loreto, Dario Maggiorini

The necessity of supporting more and more social interaction (and not only the mere information sharing) in online environments is the disruptive force upon which phenomena ascribed to the Web2.0 paradigm continuously bud. People interacting in online socio-technical environments mould technology on their needs, seamlessly integrating it into their everyday

G. Roati, C. D&#39;Errico, L. Fallani, M. Fattori

One of the most intriguing phenomena in physics is the localization of waves in disordered media. This phenomenon was originally predicted by Anderson, fifty years ago, in the context of transport of electrons in crystals. Anderson localization is actually a much more general phenomenon, and it has been observed in a large variety of systems, including light

Christian I. Johnson, Catherine A. Pilachowski, Jennifer Simmerer, Dustin Schwenk

We present radial velocities, Fe, and Al abundances for 180 red giant branch (RGB) stars in the Galactic globular cluster Omega Centauri ($ω$ Cen). The majority of our data lie in the range 11.0$<$V$<$13.5, which covers the RGB from about 1 mag. above the horizontal branch to the RGB tip. The selection procedures are biased towards preferentially observing t

Veerle Ledoux, Marnix Van Daele, Guido Vanden Berghe

Finding the eigenvalues of a Sturm-Liouville problem can be a computationally challenging task, especially when a large set of eigenvalues is computed, or just when particularly large eigenvalues are sought. This is a consequence of the highly oscillatory behaviour of the solutions corresponding to high eigenvalues, which forces a naive integrator to take in

Florentin Millour, Damien Ségransan, G. Duvert, Fabien Malbet

The following exercises aim to learn the link between the object intensity distribution and the corresponding visibility curves of a long-baseline ptical interferometer. They are also intended to show the additional constraints on observability that an interferometer has. This practical session is meant to be carried out with the ASPRO software, from the Jea

Antonio Dobado, Felipe J. Llanes-Estrada, Juan Miguel Torres Rincon

In this work we briefly review the Kovtun-Son-Starinet (KSS) computation of the ratio eta/s for quantum field theories with gravitational dual and the related conjecture that it is bound from below by 1/(4 pi). We discuss the validity of the bound and the nature of its possible violations, its relevance for RHIC, its connection with phase transitions and oth

Dmitry Yu. Ivanov, Alessandro Papa

The forward electroproduction of two light vector mesons is the first example of a collision process between strongly interacting colorless particles for which the amplitude can be written completely within perturbative QCD in the Regge limit with next-to-leading accuracy. This amplitude can be written as a convolution of two impact factors for the virtual p

Ruth Gregory

In these lectures, I give an introduction to and overview of braneworlds and black holes in the context of warped compactifications. I first describe the general paradigm of braneworlds, and introduce the Randall-Sundrum model. I discuss braneworld gravity, both using perturbation theory, and also non perturbative results. I then discuss black holes on the b

K. Kolwas, A. Derkachova, S. Demianiuk

We study the oscillation frequencies and radiative decay rates of surface plasmon modes of a simple-metal sphere as a function of sphere radius without any assumptions concerning the sphere size. We re-examine within the framework of classical electrodynamics the usual expectations for multipolar plasmon frequency in the so called &#34;low radius limit&#34;

Y. O. Hamidoune, O. Serra

Let $A,B$ be nonempty subsets of a an abelian group $G$. Let $N_i(A,B)$ denote the set of elements of $G$ having $i$ distinct decompositions as a product of an element of $A$ and an element of $B$. We prove that $$ \sum _{1\le i \le t} |N_i (A,B)|\ge t(|A|+|B|- t-α+1+w)-w, $$ where $α$ is the largest size of a coset contained in $AB$ and $w=\min (α-1,1)$, wi

Tom Coates

In this paper we analyze six examples of birational transformations between toric orbifolds: three crepant resolutions, two crepant partial resolutions, and a flop. We study the effect of these transformations on genus-zero Gromov-Witten invariants, proving the Coates-Corti-Iritani-Tseng/Ruan form of the Crepant Resolution Conjecture in each case. Our result

Cécile Appert-Rolland, Bernard Derrida, Vivien Lecomte, Frédéric Van Wijland

We calculate exactly the first cumulants of the integrated current and of the activity (which is the total number of changes of configurations) of the symmetric simple exclusion process (SSEP) on a ring with periodic boundary conditions. Our results indicate that for large system sizes the large deviation functions of the current and of the activity take a u

Allan Sly, Chris Heyde

We consider functionals of long-range dependent Gaussian sequences with infinite variance and obtain nonstandard limit theorems. When the long-range dependence is strong enough, the limit is a Hermite process, while for weaker long-range dependence, the limit is $α$-stable Lévy motion. For the critical value of the long-range dependence parameter, the limit

L. Zschiedrich, F. Schmidt

Rigorous electromagnetic field simulations are an essential part for scatterometry and mask pattern design. Today mainly periodic structures are considered in simulations. Non-periodic structures are typically modeled by large, artificially periodified computational domains. For systems with a large radius of influence this leads to very large computational

Josep Lluís Solé, Frederic Utzet

Let $X=\{X_t, t\ge0\}$ be a càdlàg Lévy process, centered, with moments of all orders. There are two families of orthogonal polynomials associated with $X$. On one hand, the Kailath--Segall formula gives the relationship between the iterated integrals and the variations of order $n$ of $X$, and defines a family of polynomials $P_1(x_1), P_2(x_1,x_2),...$ tha

Tao-Ming Wang, Jun-Lin Kuo

In 1994 S. McGuinness showed that any greedy clique decompo- sition of an n-vertex graph has at most $\lfloor n^2/4 \rfloor$ cliques (The greedy clique decomposition of a graph, J. Graph Theory 18 (1994) 427-430), where a clique decomposition means a clique partition of the edge set and a greedy clique decomposition of a graph is obtained by removing maximal

Luigi Genovese, Alexey Neelov, Stefan Goedecker, Thierry Deutsch

Daubechies wavelets are a powerful systematic basis set for electronic structure calculations because they are orthogonal and localized both in real and Fourier space. We describe in detail how this basis set can be used to obtain a highly efficient and accurate method for density functional electronic structure calculations. An implementation of this method

Hasan Yıldırım, Ceyhun Bulutay

Third-order bound-charge electronic nonlinearities of Si nanocrystals (NCs) embedded in a wide band-gap matrix representing silica are theoretically studied using an atomistic pseudopotential approach. Nonlinear refractive index, two-photon absorption and optical switching parameter are examined from small clusters to NCs up to a size of 3 nm. Compared to bu

Daniel Appel, Evija Ribnere

For an epimorphism pi of the free group F_n onto a finite group G write Gamma(G,pi) for the group of all automorphisms f of F_n for which pi*f = pi. This is called the standard congruence subgroup of Aut(F_n) associated to G and pi. In the case n = 2 we present formulas for the index of Gamma(G,pi) where G is abelian or dihedral. Moreover, we show that congr

Kosmas Kosmidis, Shlomo Havlin, Armin Bunde

We study the effects of spatial constraints on the structural properties of networks embedded in one or two dimensional space. When nodes are embedded in space, they have a well defined Euclidean distance $r$ between any pair. We assume that nodes at distance $r$ have a link with probability $p(r) \sim r^{- δ}$. We study the mean topological distance $l$ and

Eef van Beveren, George Rupp

We argue that the low-lying scalar-meson nonet makes part of a subset of a family of infinitely many scalar-meson nonets, which in turn makes part of a family of infinitely many quark-antiquark bound states and resonances. We outline the properties of this subset.

M. Kildemo, I. S. Nerbo, E. Sondergard, L. Holt

Optical measurements of nanostructured GaSb prepared by sputtering is presented. The optical response is studied by Mueller Matrix Ellipsometry (MME) in the visible range (430--850nm), and by spectroscopic ellipsometry in the range 0.6--6.5eV. The nano-structured surfaces reported in this work, consist of densely packed GaSb cones approximately 50nm high, on

Indranil Chakrabarty, B. S. Choudhury

In this work we investigate the problem of secretly broadcasting five qubit entangled state between three different partners We implement the protocol described in ref [16] on three particle W-state shared by three distant partners Alice,Bob and Charlie. The problem is interesting in the sense it is the first attempt to broadcast five qubit entangled state b

Francisco Vega Reyes, Vicente Garzo, Andres Santos

We discuss in this work the validity of the theoretical solution of the nonlinear Couette flow for a granular impurity obtained in a recent work [preprint arXiv:0802.0526], in the range of large inelasticity and shear rate. We show there is a good agreement between the theoretical solution and Monte Carlo simulation data, even under these extreme conditions.

M. S. Mizielinski, D. M. Bird, M. Persson, S. Holloway

The excitation of the electronic system induced by the adsorption of a hydrogen atom on the (111) surfaces of copper and silver is investigated using the time-dependent, mean-field Newns-Anderson model. Parameters for the model are obtained by fitting to density functional theory calculations, allowing the charge and energy transfer between adsorbate and sur

Andres Santos

This paper deals with the convergence/divergence issue of the Chapman-Enskog series expansion of the shear and normal stresses for a granular gas of inelastic hard spheres. From the exact solution of a simple kinetic model in the uniform shear and longitudinal flows, it is shown that (except in the elastic limit) both series converge and their respective rad

Nicole El Karoui, Asma Meziou

We are concerned with a new type of supermartingale decomposition in the Max-Plus algebra, which essentially consists in expressing any supermartingale of class $(\mathcal{D})$ as a conditional expectation of some running supremum process. As an application, we show how the Max-Plus supermartingale decomposition allows, in particular, to solve the American o

H. Rickman, M. Fouchard, Ch. Froeschlé, G. B. Valsecchi

We present Monte Carlo simulations of the dynamical evolution of the Oort cloud over the age of the Solar System, using an initial sample of one million test comets without any cloning. Our model includes perturbations due to the Galactic tide (radial and vertical) and passing stars. We present the first detailed analysis of the injection mechanism into obse

Hartmuth Arenhoevel

After a brief introduction into the general importance of polarization observables for the analysis of a reaction, the basic density matrix formalism for the description of polarization phenomena is outlined and illustrated by explicit examples for spin one-half and one. Then various electromagnetic processes like photoreactions and electron scattering are d

Michael Hellus, Peter Schenzel

An ideal $I$ of a local Gorenstein ring $(R, \mathfrak m)$ is called cohomologically complete intersection whenever $H^i_I(R) = 0$ for all $i \not= \height I.$ Here $H^i_I(R), i \in \mathbb Z,$ denotes the local cohomology of $R$ with respect to $I.$ For instance, a set-theoretic complete intersection is a cohomologically complete intersection. Here we study

F. K. Roepke

The major role type Ia supernovae play in many fields of astrophysics and in particular in cosmological distance determinations calls for self-consistent models of these events. Since their mechanism is believed to crucially depend on phenomena that are inherently three-dimensional, self-consistent numerical models of type Ia supernovae must be multi-dimensi

Amit Pathak, Shantanu Rastogi

The observed variations in profiles of the interstellar aromatic infrared bands correlate with the object type and are indicative of PAH populations existing i n different sources. Spectroscopic studies on PAHs can provide tools for the int erpretation of variations accompanying the AIBs. As the observed spectra results from a mix of possible species in the

Simen A. Ellingsen

The frequency spectrum of the Casimir force between two plates separated by vacuum as it appears in the Lifshitz formalism is reexamined and generalised as compared to previous works to allow for imperfectly reflecting plates. As previously reported by Ford [Phys. Rev. A \textbf{48} (1993) 2962], the highly oscillatory nature of the frequency dependence of t

J. Maíz Apellániz, E. J. Alfaro, A. Sota

We use the new reduction of the Hipparcos data (van Leeuwen 2007) and a self-consistent distance determination technique for Lutz-Kelker limited samples to obtain distances to the massive stars in the solar vicinity. The distance uncertainties for the nearest massive stars have been substantially reduced with respect to those derived from the old Hipparcos r

J. -R. Chazottes, Z. Coelho, P. Collet

Let $Δ\subsetneq\V$ be a proper subset of the vertices $\V$ of the defining graph of an aperiodic shift of finite type $(Σ_{A}^{+},§)$. Let $Δ_{n}$ be the union of cylinders in $Σ_{A}^{+}$ corresponding to the points $x$ for which the first $n$-symbols of $x$ belong to $Δ$ and let $μ$ be an equilibrium state of a Hölder potential $ϕ$ on $Σ_{A}^{+}$. We know

Sasa Prelovsek

I review the lattice simulations of light scalar mesons with quark-antiquark and tetraquark interpolating fields. Several difficulties which complicate the extraction of scalar meson masses from the scalar correlators are pointed out. One of the major difficulties is the presence of the two-pseudoscalar scattering states, which often dominate the correlator

Toshihiko Yoshikawa, Masao Ogata

Using variational cluster approach, we study influence of frustration and dimensionality on magnetic properties in the ground state of Hubbard model on a stacked square lattice in the large $U$ region (U/t=10), by changing the next-nearest-neighbor hopping, $t^{\prime}$, and the interlayer hopping, $t_{\perp}$. For small $t_{\perp}<t^{\ast}_{\perp}$ with $t^

Ryuichiro Mizuhara

We discuss the microlocal Gevrey smoothing effect for the Schrödinger equation with variable coefficients via the propagation property of the wave front set of homogenous type. We apply the microlocal exponential estimates in a Gevrey case to prove our result.

Rayda Gammag, Cristine Villagonzalo

This work investigates the influence of low temperature and broadened Landau levels on the thermodynamic properties of two-dimensional electron systems. The interplay between these two physical parameters on the magnetic field dependence of the chemical potential, the specific heat and the magnetization is calculated. In the absence of a complete theory that

D. Klimm, S. Ganschow, A. Pajaczkowska, L. Lipinska

Neodymium doped yttrium aluminum garnet powders (Nd:YAG or (Y{1-x}Nd{x})3Al5O12, x=0.15, 0.25, or 0.30, respectively) were prepared by a sol-gel technique. By DTA measurements up to 2000 deg C eutectic and liquidus temperatures could be determined. Exothermal peaks in the second and subsequent DTA heating runs indicate that the crystallized DTA samples are n

Jacob Linder, Takehito Yokoyama, Daniel Huertas-Hernando, Asle Sudbø

We study the supercurrent in a superconductor/ferromagnet/superconductor graphene junction. In contrast to its metallic counterpart, the oscillating critical current in our setup decays only weakly upon increasing exchange field and junction width. We find an unusually large residual value of the supercurrent at the oscillatory cusps due to a strong deviatio

Christopher J. Fewster, Hanno Sahlmann

We give a definition for the Wigner function for quantum mechanics on the Bohr compactification of the real line and prove a number of simple consequences of this definition. We then discuss how this formalism can be applied to loop quantum cosmology. As an example, we use the Wigner function to give a new quantization of an important building block of the H