April 2009 arXiv papers — page 49

Enrico Rossi, Dirk K. Morr

We study the renormalization of a non-magnetic impurity's scattering potential due to the presence of a massless collective spin mode at a ferromagnetic quantum critical point. To this end, we compute the lowest order vertex corrections in two- and three-dimensional systems, for arbitrary scattering angle and frequency of the scattered fermions, as well as b

J. D. Younger, C. C. Hayward, D. Narayanan, T. J. Cox

We present a merger-driven evolutionary model for the production of luminous (LIRGs) and ultraluminous infrared galaxies (ULIRGs) with warm IR colours. Our results show that simulations of gas--rich major mergers including star formation, black hole growth, and feedback can produce warm (U)LIRGs. We also find that while the warm evolutionary phase is associa

John P. Blakeslee

Surface Brightness Fluctuations (SBF) can provide useful information about the unresolved stellar content of early-type galaxies and spiral bulges. The absolute SBF magnitude Mbar in a given passband depends on the properties of the stellar population and can be predicted by population synthesis models. SBF measurements in different bandpasses are sensitive

The ArDM Collaboration, V. Boccone, P. K. Lightfoot, K. Mavrokoridis

To optimise the design of the light readout in the ArDM 1-ton liquid argon dark matter detector, a range of reflector and WLS coating combinations were investigated in several small setups, where argon scintillation light was generated by radioactive sources in gas at normal temperature and pressure and shifted into the blue region by tetraphenyl butadiene (

Cameron McA Gordon

These are problems on Heegaard splittings, that were raised at the Workshop, listed according to their contributors: David Bachman, Mario Eudave-Munoz, John Hempel, Tao Li, Yair Minsky, Yoav Moriah and Richard Weidmann. On pages 285-298 of this monograph (arxiv:0904.0017) Hyam Rubinstein gives a personal collection of problems on 3-manifolds.

Juan Souto

In this survey we discuss how geometric methods can be used to study topological properties of 3-manifolds such as their Heegaard genus or the rank of their fundamental group. On the other hand, we also discuss briefly some results relating combinatorial descriptions and geometric properties of hyperbolic 3-manifolds.

G. Bimonte, G. L. Klimchitskaya, V. M. Mostepanenko

The Lifshitz-type formulas for the free energy and Casimir-Polder force acting between an atom possessing a permanent magnetic moment and a wall made of different materials are derived. Simple model allowing analytic results is considered where the atomic magnetic susceptibility is frequency-independent and wall is made of ideal metal. Numerical computations

Kwang-Yong Choi, Dirk Wulferding, Helmuth Berger, Peter Lemmens

The quasi-one-dimensional metallic system BaVS3 with a metal-insulator transition at T_MI=70 K shows large changes of the optical phonon spectrum, a central peak, and an electronic Raman scattering continuum that evolve in a three-step process. Motivated by the observation of a strongly fluctuating precursor state at high temperatures and orbital ordering an

Michael Watson, Ken-Ichi Nishikawa

An algorithm is presented that incorporates the tensor form of Maxwell's equations in a general relativistic electromagnetic particle-in-cell code. The code simplifies to Schwartzschild space-time for a non-spinning central mass. The particle advance routine uses a fourth-order Runge-Kutta algorithm to integrate the four-velocity form of Lorentz force. T

J. Krticka, Z. Mikulasek, G. W. Henry, J. Zverko

Although photometric variations of chemically peculiar (CP) stars are frequently used to determine their rotational periods, the detailed mechanism of their light variability remains poorly understood. We simulate the light variability of the star HR 7224 using the observed surface distribution of silicon and iron. We used the TLUSTY model atmospheres calcul

Genady Grabarnik, Aaron Kershenbaum

As ontologies proliferate and automatic reasoners become more powerful, the problem of protecting sensitive information becomes more serious. In particular, as facts can be inferred from other facts, it becomes increasingly likely that information included in an ontology, while not itself deemed sensitive, may be able to be used to infer other sensitive info

Raphael Gavazzi, Christophe Adami, Florence Durret, Jean-Charles Cuillandre

Due to observational constraints, dark matter determinations in nearby clusters based on weak lensing are still extremely rare, in spite of their importance for the determination of cluster properties independent of other methods. We present a weak lensing study of the Coma cluster (redshift 0.024) based on deep images obtained at the CFHT. After obtaining p

Thomas Holst, Boris Shapiro

Given a differential operator T=\sum_{i=1}^k Q_i(z)d^i/dz^i where each Q_i(z) is a polynomial define r=max_i deg(Q_i(z)-i). Assuming that r is nonnegative we consider the following multiparameter spectral problem: for each positive integer n find all polynomials V(z) of degree at most r such that the equation T(S(z))+V(z)S(z)=0 has a polynomial solution S(z)

Pascal Mérindol, Jean-Jacques Pansiot, Stéphane Cateloin

Link state routing protocols such as OSPF or IS-IS currently use only best paths to forward IP packets throughout a domain. The optimality of sub-paths ensures consistency of hop by hop forwarding although paths, calculated using Dijkstra algorithm, are recursively composed. According to the link metric, the diversity of existing paths can be underestimated

Dawood Kothawala, T. Padmanabhan

It is well known that, for a wide class of spacetimes with horizons, Einstein equations near the horizon can be written as a thermodynamic identity. It is also known that the Einstein tensor acquires a highly symmetric form near static, as well as stationary, horizons. We show that, for generic static spacetimes, this highly symmetric form of the Einstein te

Ming-Liang Zhang, D. A. Drabold

We discuss the foundations and extend the range of applicability of the widely used Kubo-Greenwood formula (KGF) for the electronic conductivity. The conductivity is derived from the current density, and only the probability amplitude rather than the transition probability is used. It is shown that the contribution to the conductivity from degenerate states

A. J. Blustin, A. C. Fabian

The calculation of mass outflow rates of AGN winds is of great importance in understanding the role that such winds play in AGN-galaxy feedback processes. The mass outflow rates are, however, difficult to estimate since the volume filling factors of the winds are unknown. In this paper, we use constraints imposed by the observed radio emission to obtain uppe

Dmitri Bykov

By direct calculation in classical theory we derive the central extension of the off-shell symmetry algebra for the string propagating in AdS_4 x CP^3. It turns out to be the same as in the case of the AdS_5 x S^5 string. We also elaborate on the kappa-symmetry gauge and explain, how it can be chosen in a way which does not break bosonic symmetries.

F. Bagarello

We discuss a procedure to construct multi-resolution analyses (MRA) of $\Lc^2(\R)$ starting from a given {\em seed} function $h(s)$ which should satisfy some conditions. Our method, originally related to the quantum mechanical hamiltonian of the fractional quantum Hall effect (FQHE), is shown to be model independent. The role of a canonical map between certa

D. A. Head

We conduct athermal simulations of freely-cooling, viscous soft spheres around the jamming transition density ϕ_{J}, and find evidence for a growing length ξ(t) that governs relaxation to mechanical equilibrium. ξ(t) is manifest in both the velocity correlation function, and the spatial correlations in a scalar measure of local force balance which we define.

F. Bagarello, G. L. Sewell

In a recent article, Alli and Sewell formulated a new version of the Dicke-Hepp-Lieb laser model in terms of quantum dynamical semigroups, and thereby extended the macroscopic picture of the model. In the present article, we complement that picture with a corresponding microscopic one, which carries the following new results. (a) The local microscopic dynami

F. Bagarello

In this paper we generalize a strategy recently proposed by the author concerning intertwining operators. In particular we discuss the possibility of extending our previous results in such a way to construct (almost) isospectral self-adjoint operators living in different Hilbert spaces. Many examples are discussed in details. Many of them arise from the theo

Yu. I. Yermolaev, I. G. Lodkina, N. S. Nikolaeva, M. Yu. Yermolaev

To measure the floor in interplanetary magnetic field and estimate the time- invariant open magnetic flux of Sun, it is necessary to know a part of magnetic field of Sun carried away by CMEs. In contrast with previous papers, we did not use global solar parameters: we identified different large-scale types of solar wind for 1976-2000 interval, obtained a fra

F. Bagarello

In this paper we discuss a general strategy to construct vector coherent states of the Gazeau-Klauder type and we use them to built up examples of isospectral hamiltonians. For that we use a general strategy recently proposed by the author and which extends well known facts on intertwining operators. We also discuss the possibility of constructing non-isospe

F. Bagarello

We propose an extension of {\em supersymmetric quantum mechanics} which produces a family of isospectral hamiltonians. Our procedure slightly extends the idea of intertwining operators. Several examples of the construction are given. Further, we show how to build up vector coherent states of the Gazeau-Klauder type associated to our hamiltonians.

F. Bagarello

We review some applications of the perturbative technique known as the {\em stochastic limit approach} to the analysis of the following many-body problems: the fractional quantum Hall effect, the relations between the Hepp-Lieb and the Alli-Sewell models (as possible models of interaction between matter and radiation), and the open BCS model of low temperatu

F. Bagarello

In this paper we show that the dissipative version of the laser model proposed by Alli and Sewell can be obtained by considering the stochastic limit of the (open system) hamiltonian introduced by Hepp and Lieb in their seminal work. We also prove that the Dicke-Haken-Lax hamiltonian produces, after the stochastic limit is considered, the generator of a semi

J. Lopez-Santiago, G. Micela, D. Montes

The associations and moving groups of young stars are excellent laboratories for investigating stellar formation in the solar neighborhood. Previous results have confirmed that a non-negligible fraction of old main-sequence stars is present in the lists of possible members of young stellar kinematic groups. A detailed study of the properties of these samples

F. Bagarello

In this paper we show how the perturbative procedure known as {\em stochastic limit} may be useful in the analysis of the Open BCS model discussed by Buffet and Martin as a spin system interacting with a fermionic reservoir. In particular we show how the same values of the critical temperature and of the order parameters can be found with a significantly sim

F. Bagarello

In two previous papers the author introduced a multiplication of distributions in one dimension and he proved that two one-dimensional Dirac delta functions and their derivatives can be multiplied, at least under certain conditions. Here, mainly motivated by some engineering applications in the analysis of the structures, we propose a different definition of

F. Bagarello

In a previous paper we have introduced a class of multiplications of distributions in one dimension. Here we furnish different generalizations of the original definition and we discuss some applications of these procedures to the multiplication of delta functions and to quantum field theory.

F. Bagarello

We introduce a new class of multiplications of distributions in one dimension merging together two different regularizations of distributions. Some of the features of these multiplications are discussed in a certain detail. We use our theory to study a certain number of examples, involving products between Dirac delta functions and its successive derivatives

Peter B Shalen

Some conjectures about Heegaard genera and ranks of fundamental groups of 3-manifolds are formulated, and it is shown that they imply new statements about hyperbolic volume.

Pietro M. Reviglio, David J. Helfand

In this third of a series of papers concerning active galaxies in the FIRST and Sloan Digital Sky Surveys, we analyze the spectroscopic and radio properties of a sample of narrow-line Active Galactic Nuclei (AGN), broad-line Seyfert I galaxies, and Quasars in the local universe in order to investigate the dependence of their activity on the mass, spin and ac

Christophe Cuny

We obtain pointwise ergodic theorems with rate under conditions expressed in terms of the convergence of series involving $\|\sum_{k=1} ^nf\circ θ^k\|_2$, improving previous results. Then, using known results on martingale approximation, we obtain some LIL for stationary ergodic processes and quenched central limit theorems for functional of Markov chains. T

Abhay Ashtekar

There is a precise sense in which the requirement of background independence suffices to uniquely select the kinematics of loop quantum gravity (LQG). Specifically, the fundamental kinematic algebra of LQG admits a unique diffeomorphism invariant state. Although this result has been established rigorously, it comes as a surprise to researchers working with o

Saul Schleimer

This note is an exposition of Waldhausen's proof of Waldhausen's Theorem: the three-sphere has a single Heegaard splitting, up to isotopy, in every genus. As a necessary step we also give a sketch of the Reidemeister-Singer Theorem.

M. M. Maslov, A. I. Podlivaev, L. A. Openov

Parameters of the nonorthogonal tight-binding model for hydrocarbons are derived based on a criterion of the best agreement between the calculated and experimental values of bond lengths and binding energies for different molecules CnHm. The results obtained can be used, e. g., to study the kinetics of hydrogen absorption by carbon nanostructures, to simulat

Andrew Hubery

These are notes from my mini-course at ICRA13, Sao Paulo, 2008

Brian Clarke

We give a description of the completion of the manifold of all smooth Riemannian metrics on a fixed smooth, closed, finite-dimensional, orientable manifold with respect to a natural metric called the $L^2$ metric. The primary motivation for studying this problem comes from Teichmueller theory, where similar considerations lead to a completion of the well-kno

Fabio D. A. Aarao Reis

A cell dynamics method for domain separation of diblock copolymers (DBCPs) interacting with nanoparticles (NPs) whose diffusion coefficients depend on chain configuration is proposed for self-assembly of DBCP/NP composites. Increasing NP concentration slows down domain separation, but matching NP diffusion lengths and lamellar size of DBCPs reduces this effe

Martha Gutiérrez, Arseni Goussev

The Loschmidt echo (LE) (or fidelity) quantifies the sensitivity of the time evolution of a quantum system with respect to a perturbation of the Hamiltonian. In a typical chaotic system the LE has been previously argued to exhibit a long-time saturation at a value inversely proportional to the effective size of the Hilbert space of the system. However, until

Grigori Rozenblum

We discuss resent developments in the problem of description of finite rank Toeplitz operators in different Bergman spaces and give some applications in analysis and mathematical physics

Juan A. Calzada, Javier Negro, Mariano A. del Olmo

We present an algebraic study of a kind of quantum systems belonging to a family of superintegrable Hamiltonian systems in terms of shape-invariant intertwinig operators, that span pairs of Lie algebras like $(su(n),so(2n))$ or $(su(p,q),so(2p,2q))$. The eigenstates of the associated Hamiltonian hierarchies belong to unitary representations of these algebras

A. N. Sazonov

We report four-color WBVR photoelectric photometry of the close binary system (CBS) HZ HER/HER X-1 made in 1986-1994. Our photometry usually covered at least two 35d precession periods during each of the 1986-1990, 1992, and 1994 observing seasons. The accuracy and duration of our 10-year long photoelectric observations of the star with an x-ray source made

Andrea Donarini, Georg Begemann, Milena Grifoni

Single particle interference lies at the heart of quantum mechanics. The archetypal double-slit experiment has been repeated with electrons in vacuum up to the more massive $C_{60}$ molecules. Mesoscopic rings threaded by a magnetic flux provide the solid-state analogous. Intra-molecular interference has been recently discussed in molecular junctions. Here w

Alejandro Lorca, Jose Luis Vazquez-Poletti, Eduardo Huedo, Ignacio M. Llorente

A program calculating Bhabha scattering at high energy colliders is considered for porting to the EGEE Grid infrastructure. The program code, which is a result of the aITALC project, is ported by using a master-worker operating scheme. The job submission, execution and monitoring are implemented using the GridWay metascheduler. The unattended execution of jo

F. Suzuki-Vidal, S. V. Lebedev, A. Ciardi, S. N. Bland

We report on experiments in which magnetically driven radiatively cooled plasma jets were produced by a 1 MA, 250 ns current pulse on the MAGPIE pulsed power facility. The jets were driven by the pressure of a toroidal magnetic field in a ''magnetic tower'' jet configuration. This scenario is characterized by the formation of a magnetically c

J. M. Pittard

The dynamics of the wind-wind collision in massive stellar binaries is investigated using three-dimensional hydrodynamical models which incorporate gravity, the driving of the winds, the orbital motion of the stars, and radiative cooling of the shocked plasma. In this first paper we restrict our study to main-sequence O+O binaries. The nature of the wind-win

Jonathan P. Dowling

Quantum states of light, such as squeezed states or entangled states, can be used to make measurements (metrology), produce images, and sense objects with a precision that far exceeds what is possible classically, and also exceeds what was once thought to be possible quantum mechanically. The primary idea is to exploit quantum effects to beat the shot-noise

Juergen Geiser

In this paper we describe an iterative operator-splitting method for unbounded operators. We derive error bounds for iterative splitting methods in the presence of unbounded operators and semigroup operators. Here mixed applications of hyperbolic and parabolic type are allowed and discussed in the applications. Mixed experiments are applied to ordinary diffe

Brian Clarke

This is the author's Ph.D. thesis, submitted to the University of Leipzig. It deals with the $L^2$ Riemannian metric on the manifold of all smooth Riemannian metrics on a fixed closed, finite-dimensional manifold. The main body of the thesis is a description of the completion manifold of metrics with respect to the $L^2$ metric. The primary motivation fo

James O. Berger, José M. Bernardo, Dongchu Sun

Reference analysis produces objective Bayesian inference, in the sense that inferential statements depend only on the assumed model and the available data, and the prior distribution used to make an inference is least informative in a certain information-theoretic sense. Reference priors have been rigorously defined in specific contexts and heuristically def

N. Cherroret, S. E. Skipetrov

We theoretically study the influence of weak interactions on the diffusive expansion of a Bose-Einstein condensate in a three-dimensional random potential. For this purpose we develop a perturbative approach and calculate analytically the first-order nonlinear correction to the ensemble-averaged atomic density as a function of position and time. We find that

Andrey E. Miroshnichenko

We study light scattering by spheres made of negative refractive index materials. We demonstrate that scattering efficiency of the light does not always obey the well-known Rayleigh's law $Q_{\rm sca}\sim1/λ^4$ for small values of size parameter, but could be wavelength independent $Q_{\rm sca}\sim const$, or even increase with the wavelength as $Q_{\rm

Fabian Walter

Although dust emission at cosmological distances has only been detected a little more than a decade ago, remarkable progress has been achieved since then in characterizing the far-infrared emission of high-redshift systems. The mere fact that dust can be detected in galaxies at high redshift is remarkable for two reasons: (a) even at very early cosmic epochs

M. Lestinsky, N. R. Badnell, D. Bernhardt, M. Grieser

We have measured electron-ion recombination for Fe$^{9+}$ forming Fe$^{8+}$ and for Fe$^{10+}$ forming Fe$^{9+}$ using merged beams at the TSR heavy-ion storage-ring in Heidelberg. The measured merged beams recombination rate coefficients (MBRRC) for relative energies from 0 to 75 eV are presented, covering all dielectronic recombination (DR) resonances asso

M. Cadoni, R. De Leo, S. Demelio, G. Gaeta

We report on numerical investigations concerning the propagation of solitons in a real DNA chain (the Human Adenovirus 2) using a realistic model of DNA torsional dynamics; this takes fully into account the inhomogeneities in the real chain. We find that twist solitons propagate for considerable distances (2-10 times their diameters) before stopping due to p

C. P. Padilla-Torres, C. M. Gutierrez, R. Rebolo, R. Genova-Santos

We study the spatial distribution and colours of galaxies within the region covered by the cold spot in the cosmic microwave background (CMB) recently detected by the Very Small Array (VSA; Genova-Santos et al. 2005, 2008) towards the Corona Borealis supercluster (CrB-SC). The spot is in the northern part of a region with a radius ~1 degree (~5 Mpc at the re

E. Cancellieri, F. Troiani, G. Goldoni

We show theoretically that nearly indistinguishable photons can be generated with non-identical semiconductor-based sources. The use of virtual Raman transitions and the optimization of the external driving fields increases the tolerance to spectral inhomogeneity to the meV energy range. A trade-off emerges between photon indistinguishability and efficiency

Raza Ur-Rehman, Stéphane Caro, Damien Chablat, Philippe Wenger

This paper deals with the kinematics and dynamics of a two degree of freedom spherical manipulator, the wrist of Orthoglide 5-axis. The latter is a parallel kinematics machine composed of two manipulators: i) the Orthoglide 3-axis; a three-dof translational parallel manipulator that belongs to the family of Delta robots, and ii) the Agile eye; a two-dof para

Henrik N. Latter, Gordon I. Ogilvie

This paper addresses the fine-scale axisymmetric structure exhibited in Saturn's A and B-rings. We aim to explain both the periodic microstructure on 150-220m, revealed by the Cassini UVIS and RSS instruments, and the irregular variations in brightness on 1-10km, reported by the Cassini ISS. We propose that the former structures correspond to the peaks a

B. Garcia-Lorenzo, A. Eff-Darwich, J. J. Fuensalida, J. Castro-Almazan

Current projects for large telescopes demand a proper knowledge of atmospheric turbulence to design efficient adaptive optics systems in order to reach large Strehl ratios. However, the proper characterization of the turbulence above a particular site requires long-term monitoring. Due to the lack of long-term information on turbulence, high-altitude winds (

A. Eff-Darwich, B. Garcia-Lorenzo, J. A. Rodriguez-Losada, J. de la Nuez

An analysis of the impact of seismic and volcanic activity was carried out at selected astronomical sites, namely the observatories of El Teide (Tenerife, Canary Islands), Roque de los Muchachos (La Palma, Canary Islands), Mauna Kea (Hawaii) and Paranal (Chile) and the candidate site of Cerro Ventarrones (Chile). Hazard associated to volcanic activity is low

Fabrice Sthal, Serge Galliou, Joël Imbaud, Xavier Vacheret

The first step, before investigating physical origins of noise in resonators, is to investigate correlations between external measurement parameters and the resonator noise. Tests and measurements are mainly performed on an advanced phase noise measurement system, recently set up. The resonator noise is examined as a function of the sensitivity to the drive

Aiguo Xu, Guangcai Zhang, X. F. Pan, Jianshi Zhu

Direct modeling of porous materials under shock is a complex issue. We investigate such a system via the newly developed material-point method. The effects of shock strength and porosity size are the main concerns. For the same porosity, the effects of mean-void-size are checked. It is found that, local turbulence mixing and volume dissipation are two import

Karl-Hermann Neeb

Locally affine Lie algebras are generalizations of affine Kac--Moody algebras with Cartan subalgebras of infinite rank whose root system is locally affine. In this note we study a class of representations of locally affine algebras generalizing integrable highest weight modules. In particular, we construct such an integrable representation for each integral

Antonio J. Di Scala, Oscar Macia

A polynomial whose coeffcients are equal to its roots is called a Ulam polynomial. In this paper we show that for a given degree n there exists a finite number of Ulam polynomials of degree n.

G. Ruediger, M. Gellert, M. Schultz

The potential of the nonaxisymmetric magnetic instability to transport angular momentum and to mix chemicals is probed considering the stability of a nearly uniform toroidal field between conducting cylinders with different rotation rates. The fluid between the cylinders is assumed as incompressible and to be of uniform density. With a linear theory the neut

Alwyn Wootten, Bryan Butler, Antonio Hales, Stuartt Corder

Stars and planets are the fundamental objects of the Universe. Their formation processes, though related, may differ in important ways. Stars almost certainly form from gravitational collapse and probably have formed this way since the first stars lit the skies. Although it is possible that planets form in this way also, processes involving accretion in a ci

Aiguo Xu, Guangcai Zhang, X. F. Pan, Ping Zhang

Morphological measures are introduced to probe the complex procedure of shock wave reaction on porous material. They characterize the geometry and topology of the pixelized map of a state variable like the temperature. Relevance of them to thermodynamical properties of material is revealed and various experimental conditions are simulated. Numerical results

J. B. Roos, M. Larsson, AA. Larson, A. E Orel

The cross section for dissociative recombination of BeH^+ is calculated by solution of the time-dependent Schrodinger equation in the local complex potential approximation. The effects of couplings between resonant states and the Rydberg states converging to the ground state of the ion are studied. The relevant potentials, couplings and autoionization widths

Jonathan Asher Cohen

General coherence theorems are constructed that yield explicit presentations of categorical and algebraic objects. The categorical structures involved are finitary discrete Lawvere 2-theories, though they are approached within the language of term rewriting theory. Two general coherence theorems are obtained. The first applies to terminating and confluent re

G. V. Dedkov, A. A. Kyasov

For the first time, we calculate the heating rate, attractive conservative and tangential dissipative fluctuation electromagnetic forces felt by a thick plate moving parallel to a closely spaced another plate in rest using a nonrelativistic approximation of fluctuation electrodynamics. These results can be considered as the high lights when solving general r

T. Chanier, F. Virot, R. Hayn

We have calculated the chemical trend of magnetic exchange parameters ($J_{dd}$, $N α$, and $N β$) of Zn-based II-VI semiconductors ZnA (A=O, S, Se, and Te) doped with Co or Mn. We show that a proper treatment of electron correlations by the LSDA+$U$ method leads to good agreement between experimental and theoretical values of the nearest-neighbor exchange c

Kyle W. Martin, Siming Liu, Chris Fragile, Cong Yu

Sagittarius A* is a compact radio source at the Galactic center, powered by accretion of fully ionized plasmas into a supermassive black hole. However, the radio emission cannot be produced through the thermal synchrotron process by a gravitationally bounded flow. General relativistic magneto-hydrodynamical(GRMHD) simulations of black hole accretion show tha

I. R. Shein, A. L. Ivanovskii

First principle FLAPW-GGA calculations have been performed with the purpose to understand the electronic properties for the newly synthesized tetragonal (space group P4/nmm) layered iron arsenide-oxide: Sr4Sc2Fe2As2O6 doped with titanium. The total and partial densities of states, low-temperature electron specific heat and molar Pauli paramagnetic susceptibi

Balázs Dóra, Ferenc Simon

Theory of nuclear magnetic resonance (NMR) in graphene is presented. The canonical form of the electron-nucleus hyperfine interaction is strongly modified by the linear electronic dispersion. The NMR shift and spin-lattice relaxation time are calculated as function of temperature, chemical potential, and magnetic field and three distinct regimes are identifi

Gido Scharfenberger-Fabian

A Souslin algebra is a complete Boolean algebra whose main features are ruled by a tight combination of an antichain condition with an infinite distributive law. The present article divides into two parts. In the first part a representation theory for the complete and atomless subalgebras of Souslin algebras is established (building on ideas of Jech and Jens

O. T. Kosmas, D. S. Vlachos

In this work, the benefits of the phase fitting technique are embedded in high order discrete Lagrangian integrators. The proposed methodology creates integrators with zero phase lag in a test Lagrangian in a similar way used in phase fitted numerical methods for ordinary differential equations. Moreover, an efficient method for frequency evaluation is propo

J. Sadeghi, F. Milani, A. R. Amani

In this paper we consider a non-minimally coupled scaler field, and show its equation of state parameter can crossing over -1, $ω\to -1$, and bouncing condition. Also we obtain the stability conditions and consider reconstructing for our model.

Michael Huber

We give new combinatorial constructions for codes providing authentication and secrecy for equiprobable source probability distributions. In particular, we construct an infinite class of optimal authentication codes which are multiple-fold secure against spoofing and simultaneously achieve perfect secrecy. Several further new optimal codes satisfying these p

T. Stoecklin

We study the variation of the positions of two magnetically tuned Zero energy Feshbach resonances when a parallel superimposed electric field is applied. We show that their variation as a function of the electric field follows a simple analytical law and is then predictable. We find that depending on the initial state of the diatomic molecule the resonance i

J. Novotny, G. Alber, I. Jex

We investigate the asymptotic dynamics of quantum networks under repeated applications of random unitary operations. It is shown that in the asymptotic limit of large numbers of iterations this dynamics is generally governed by a typically low dimensional attractor space. This space is determined completely by the unitary operations involved and it is indepe

Nora Muler, Daniel Peña, Víctor J. Yohai

This paper introduces a new class of robust estimates for ARMA models. They are M-estimates, but the residuals are computed so the effect of one outlier is limited to the period where it occurs. These estimates are closely related to those based on a robust filter, but they have two important advantages: they are consistent and the asymptotic theory is tract

S. Hekker, Y. Fremat, P. Lampens, P. De Cat

A variety of physical processes leading to different types of pulsations and chemical compositions is observed among A- and F-type stars. To investigate the underlying mechanisms responsible for these processes in stars with similar locations in the H-R diagram, an accurate abundance determination is needed, among others. Here, we describe a semi-automatic p

Erling Stormer

It is shown that a trace invariant projection map, i.e. a positive unital idempotent map, of a finite dimensional C*-algebra into itself is non-decomposable if and only if it is atomic, or equivalently not the sum of a 2-positive and a 2-copositive map. In particular projections onto spin factors of dimension greater than 6 are atomic.

S. M. Vinko, G. Gregori, B. Nagler, T. J. Whitcher

We present calculations of the free-free XUV opacity of warm, solid-density aluminum at photon energies between the plasma frequency at 15 eV and the L-edge at 73 eV, using both density functional theory combined with molecular dynamics and a semi-analytical model in the RPA framework with the inclusion of local field corrections. As the temperature is incre

Elie Bretin, Morgan Brassel

This paper is concerned with the motion of a time dependent hypersurface that evolves by mean curvature flow with a a volume constraint. Phase field approximation of this motion leads to the well known nonlocal Allen--Cahn equation. Here we propose a modified version of this equation, and we show that it has better volume preserving properties than the class

Junfeng Liu, Zhongshui Ma

Characterized by zigzag and armchair boundaries, the narrow ribbons display the very different characteristics in Hall conductivities. It is shown that the multi-band-crossings occur in the energy spectrum for armchair ribbons, and the number of them depends on the width of ribbons. Theoretically, it is predicated that the conductivities exhibit drastic sign

K. -I. Nishikawa, J. Niemiec, P. E. Hardee, M. Medvedev

Plasma instabilities (e.g., Buneman, Weibel and other two-stream instabilities) excited in collisionless shocks are responsible for particle (electron, positron, and ion) acceleration. Using a new 3-D relativistic particle-in-cell code, we have investigated the particle acceleration and shock structure associated with an unmagnetized relativistic electron-po

Marcos Dajczer, Pedro Morais

The goal of this paper is to classify parametrically parabolic submanifolds in any codimension. First, we describe the ones that are ruled and show that they are the only parabolic submanifolds that admit an isometric immersion as a hypersurface. Then, we classify the nonruled ones by two different means. In fact, we provide the polar and bipolar parametriza

Geurt Jongbloed, Frank H. van der Meulen

We consider two nonparametric procedures for estimating a concave distribution function based on data corrupted with additive noise generated by a bounded decreasing density on $(0,\infty)$. For the maximum likelihood (ML) estimator and least squares (LS) estimator, we state qualitative properties, prove consistency and propose a computational algorithm. For

Michal Matuszewski, Tristram J. Alexander, Yuri S. Kivshar

We analyze the structure of spin-1 Bose-Einstein condensates in the presence of a homogenous magnetic field. We classify the homogenous stationary states and study their existence, bifurcations, and energy spectra. We reveal that the phase separation can occur in the ground state of polar condensates, while the spin components of the ferromagnetic condensate

John J. Oh, Wontae Kim

The absorption cross section for the the warped AdS$_3$ black hole background shows that it is larger than the area even if the s-wave limit is considered. It raises some question whether the deviation from the areal cross section is due to the warped configuration of the geometry or the rotating coordinate system, where these two effects are mixed up in the

Alexander Knebe, Christian Wagner, Steffen Knollmann, Tobias Diekershoff

We systematically study the effects of varying the starting redshift z_i for cosmological simulations in the highly non-linear regime. Our primary focus lies with the (individual) properties of dark matter halos -- namely the mass, spin, triaxiality, and concentration -- where we find that even substantial variations in z_i leave only a small imprint, at lea

M. Rybak, A. Dydejczyk, K. Kulakowski

The norm game (NG) introduced by Robert Axelrod is a convenient frame to disccuss the time evolution of the level of preserving norms in social systems. Recently NG was formulated in terms of a social contagion on a model social network with two stable states: defectors or punishers. Here we calculate the critical line between these states on the plane of pa

Huixia Judy Wang, Mendel Fygenson

We develop inference procedures for longitudinal data where some of the measurements are censored by fixed constants. We consider a semi-parametric quantile regression model that makes no distributional assumptions. Our research is motivated by the lack of proper inference procedures for data from biomedical studies where measurements are censored due to a f

M. Barnabei, F. Bonetti, M. Silimbani

We exploit Krattenthaler's bijection between the set $S_n(3\textrm{-}1\textrm{-}2)$ of permutations in $S_n$ avoiding the classical pattern $3\textrm{-}1\textrm{-}2$ and Dyck $n$-paths to study the distribution of every consecutive pattern of length 3 on the set $S_n(3\textrm{-}1\textrm{-}2)$. We show that these consecutive patterns split into 3 equidist

Madad Khan, Muhammad Nouman Aslam Khan

In the present paper we have studied the concept of fuzzification in AG-groupoids. The equivalent statement for an AG-groupoid to be a commutative semigroup is proved. Fuzzy points have been defined in an AG-groupoid and has been shown the representation of smallest fuzzy left ideal generated by a fuzzy point. The set of all fuzzy left ideals, which are idem