November 2008 arXiv papers — page 21

Kenneth G. Libbrecht, Helen C. Morrison, Benjamin Faber

We present a series of experiments investigating the growth of ice crystals from water vapor in the presence of a background gas. We measured growth dynamics at temperatures ranging from -2 C to -25 C, at supersaturations between 0.5 and 30 percent, and with background gases of nitrogen, argon, and air at a pressure of one bar. We compared our data with nume

A. Baule, E. G. D. Cohen

We study the work fluctuations of a particle, confined to a moving harmonic potential, under the influence of friction and external Poissonian shot noise. The asymmetry of the noise induces an effective nonlinearity in the potential, which in turn leads to singular features in the work distribution. On the basis of an analytic solution we find that the conve

V. Straizys, V. Laugalys

Star formation in the Local spiral arm in the direction of the Galactic longitudes 132--158 deg is reviewed. Recent star-forming activity in this Milky Way direction is evidenced by the presence here of the Cam OB1 association and dense dust and molecular clouds containing H$α$ emission stars, young irregular variables and infrared stellar objects. The cloud

Olivier Lablée

In this article we describe the semi-classical spectrum of a Schrodinger operator on $\mathbb{R}$ with a double well potential. We study the shape of spectrum around the local maximum of the potential. In the classification of singularities of integrable systems, the double wells is the model of non-degenerate hyperbolic singularity.

Zbigniew J. Jurek

It is shown that operator-selfdecomposable measures, or more precisely their Urbanik decomposability semigroups, induce generalized Mehler semigroups of bounded linear operators. Moreover, those semigroups can be represented as random integrals of operator valued functions with respect to stochastic Lévy processes. Our Banach space setting is in the contrast

Jean Bertoin, Vladas Sidoravicius

The initial purpose of this work is to provide a probabilistic explanation of a recent result on a version of Smoluchowski's coagulation equations in which the number of aggregations is limited. The latter models the deterministic evolution of concentrations of particles in a medium where particles coalesce pairwise as time passes and each particle can o

Juergen Reingruber, david Holcman

The early steps of light response occur in the outer segment of rod and cone photoreceptor. They involve the hydrolysis of cGMP, a soluble cyclic nucleotide, that gates ionic channels located in the outer segment membrane. We shall study here the rate by which cGMP is hydrolyzed by activated phosphodiesterase (PDE). This process has been characterized experi

Amaury Mouchet

It is shown how the model which was introduced by Mouchet (2008 Eur. J. Phys. 29 1033) allows one to mimic the quantum tunnelling between two symmetric one-dimensional wells.

Dominique Cancellieri, Eric Leoni, Jean Louis Rossi

The scope of this work was the determination of kinetic parameters of the thermal oxidative degradation of a Mediterranean scrub using a hybrid method developed at the laboratory. DSC and TGA were used in this study under air sweeping to record oxidative reactions. Two dominating and overlapped exothermic peaks were recorded in DSC and individualized using a

Alexandre Goldsztejn

Proving the existence of a solution to a system of real equations is a central issue in numerical analysis. In many situations, the system of equations depend on parameters which are not exactly known. It is then natural to aim proving the existence of a solution for all values of these parameters in some given domains. This is the aim of the parametrization

Alejandro Corichi, Parampreet Singh

A recent Comment [arXiv:0811.2790] on the Letter 'Quantum Bounce and Cosmic Recall' by the authors is shown to arise from an incorrect understanding of the issues at hand and of our analysis. The conclusions of Bojowald's Comment are shown to add little to our work, to be irrelevant at best, and are further shown to be in contradiction with his o

Gh. Nenciu, I. Nenciu

Let $Ω$ be a bounded domain in $R^n$ with $C^2$-smooth boundary of co-dimension 1, and let $H=-Δ+V(x)$ be a Schrödinger operator on $Ω$ with potential V locally bounded. We seek the weakest conditions we can find on the rate of growth of the potential V close to the boundary which guarantee essential self-adjointness of H on $C_0^\infty(Ω)$. As a special cas

Fred J. Rispoli

The (k,d)-hypersimplex is a (d-1)-dimensional polytope whose vertices are the (0,1)-vectors that sum to k. When k=1, we get a simplex whose graph is the complete graph with d vertices. Here we show how many of the well known graph parameters and attributes of the complete graph extend to a more general case. In particular we obtain explicit formulas in terms

Manuel Peimbert

I present a brief review on the determination of the primordial helium abundance by unit mass, Yp. I discuss the importance of the primordial helium abundance in: (a) cosmology, (b) testing the standard big bang nucleosynthesis, (c) studying the physical conditions in H II regions, (d) providing the initial conditions for stellar evolution models, and (e) te

Berndt Müller

The QCD matter produced in nuclear collisions at the Relativistic Heavy Ion Collider (RHIC) has been found to have a very low shear viscosity, which is close to the lower bound allowed by unitarity. The matter has also been found to strongly suppress the emission of energetic hadrons. This phenomenon, called "jet quenching" is interpreted to be the r

Samir Mandal, Sandip K. Chakrabarti

We calculate the spectra of two-component accretion flows around black holes of various masses, from quasars to nano-quasars. Specifically, we fit the observational data of M87 very satisfactorily using our model and find that the spectrum may be well fitted by a sub-Keplerian component alone, and there is little need of any Keplerian component. The non-ther

Alison Sills, Amanda Karakas, John Lattanzio

We study the post-main sequence evolution of products of collisions between main sequence stars (blue stragglers), with particular interest paid to the horizontal branch and asymptotic giant branch phases. We found that the blue straggler progeny populate the colour-magnitude diagram slightly blueward of the red giant branch and between 0.2 and 1 magnitudes

D. J. Garcia, F. A. Garcia, J. G. S. Duque, P. G. Pagliuso

Despite extensive research on the skutterudites for the last decade, their electric crystalline field ground state is still a matter of controversy. We show that Electron Spin Resonance (ESR) measurements can determine the full set of crystal field parameters (CFPs) for the Th cubic symmetry (Im3) of the Ce$_{1-x}$R$_{x}$Fe$_{4}$P$_{12}$ (R = Dy, Er, Yb, $x\

N. Eddy, J. L. Crisp, M. Hu

The primary purpose of the Fermilab Recycler Ring Transverse Digital Damper System is to prevent instabilities due to high phase space densities of the cooled antiproton beam. The system was designed to facilitate Beam Transfer Function measurements using a signal analyzer connected to auxiliary system ports for timing and diagnostic purposes. The Digital Da

M. A. Vincenti, A. D Orazio, M. G. Cappeddu, Neset Akozbek

We theoretically demonstrate negative refraction and sub-wavelength resolution below the diffraction limit in the UV and extreme UV ranges using semiconductors. The metal-like re-sponse of typical semiconductors such as GaAs or GaP makes it possible to achieve negative refraction and super-guiding in resonant semiconductor/dielectric multilayer stacks, simil

Chen-Yu Chi, Shing-Tung Yau

A classical set of birational invariants of a variety are its spaces of pluricanonical forms and some of their canonically defined subspaces. Each of these vector spaces admits a typical metric structure which is also birationally invariant. These vector spaces so metrized will be referred to as the pseudonormed spaces of the original varieties. A fundamenta

L. Ostorero, R. Moderski, L. Stawarz, M. C. Begelman

The study of the broad-band emission of GHz-Peaked-Spectrum (GPS) radio galaxies is a powerful tool to investigate the physical processes taking place in the central, kpc-sized region of their active hosts, where the jets propagate and the lobes expand, interacting with the surrounding interstellar medium (ISM). We recently developed a new dynamical-radiativ

F. Rahoui, S. Chaty, J. Rodriguez, Y. Fuchs

We report preliminary results of mid-infrared (MIR) and X-ray observations of GRS 1915+105 that we carried out between 2004 October 2 and 2006 June 5. Our main goals were to study its variability, to detect the presence of dust, and to investigate the possible links between MIR and X-ray emissions. We performed photometric and spectroscopic observations of G

R. Campoamor-Stursberg, M. Rausch de Traubenberg

We study supersymmetric extensions of classical kinematical algebras from the point of view of contraction theory. It is shown that contracting the supersymmetric extension of the anti-de Sitter algebra leads to a hierarchy similar in structure to the classical Bacry-Lévy-Leblond classification

C. Józsa, M. Popinciuc, N. Tombros, H. T. Jonkman

Electrical spin injection from ferromagnetic metals into graphene is hindered by the impedance mismatch between the two materials. This problem can be reduced by the introduction of a thin tunnel barrier at the interface. We present room temperature non-local spin valve measurements in cobalt/aluminum-oxide/graphene structures with an injection efficiency as

Paul Sorensen

Recent data from heavy ion collisions at RHIC show strong near-side correlations extending over several units of rapidity. This ridge-like correlation exhibits an abrupt onset with collision centrality. In this talk, I argue that the centrality and beam-energy dependence of these near-angle correlations could provide access to information about the Quark Glu

J. C. Owen, S. C. Power

Some aspects of a mathematical theory of rigidity and flexibility are developed for general infinite frameworks and two main results are obtained. In the first sufficient conditions, of a uniform local nature, are obtained for the existence of a proper flex of an infinite framework. In the second it is shown how continuous paths in the plane may be simulated

Alakabha Datta, Maxime Imbeault, David London

We consider the new-physics (NP) solution to the polarization puzzle in B -> phi K* decays. We note that any such solution must reproduce the data in B -> phi Ks, where there are disagreements with the standard model in CP-asymmetry measurements. We examine 10 NP operators, of S/P, V/A and T variety. We find that, as long as B -> phi Ks exhibits large CP-vio

Claudia Hagedorn, Michael A. Schmidt, Alexei Yu. Smirnov

In SO(10) grand unified theories (GUTs) the hierarchy which is present in the Dirac mass term of the neutrinos is generically as strong as the one in the up-type quark mass term. We propose a mechanism to partially or completely cancel this hierarchy in the light neutrino mass matrix in the seesaw context. The two main ingredients of the cancellation mechani

Nga T. T. Nguyen, F. M. Peeters

The energy spectrum of a one-electron quantum dot doped with a single magnetic ion is studied in the presence of an external magnetic field. The allowed cyclotron resonance (CR) transitions are obtained together with their oscillator strength (OS) as function of the magnetic field, the position of the magnetic ion, and the quantum dot confinement strength. W

Nicolas Sangouard, Christoph Simon, Thomas Coudreau, Nicolas Gisin

We show that single-photon entangled states of the form |0>|1>+|1>|0> can be purified with a simple linear-optics based protocol, which is eminently feasible with current technology. Besides its conceptual interest, this result is relevant for attractive quantum repeater protocols.

P. M. Tomchuk

General expressions are obtained for the coefficient of light absorption by free carriers as well as the intensity of the spontaneous light emission by hot electrons in multivalley semiconductors. These expressions depend on the electron concentration and electron temperature in the individual valleys. An anisotropy of the dispersion law and electron scatter

M. Catelan

Horizontal branch (HB) stars play a particularly important role in the "age debate," since they are at the very center of the long-standing "second parameter" problem. In this review, I discuss some recent progress in our understanding of the nature and origin of HB stars.

E. I. Vorobyov, Christian Theis

We expand our pervious numerical study of the properties of the stellar velocity distribution within the disk of a two-armed spiral galaxy by considering spiral stellar density waves with different global Fourier amplitudes, C_2. We confirm our previous conclusion that the ratio σ_1:σ_2 of smallest versus largest principal axes of the stellar velocity ellips

Nga T. T. Nguyen, F. M. Peeters

The electron-electron correlations in a many-electron (Ne = 1, 2,..., 5) quantum dot confined by a parabolic potential is investigated in the presence of a single magnetic ion and a perpendicular magnetic field. We obtained the energy spectrum and calculated the addition energy which exhibits cusps as function of the magnetic field. The vortex properties of

Howard E. Bond, William B. Sparks

The luminous Galactic Cepheid RS Puppis is unique in being surrounded by a dust nebula illuminated by the variable light of the Cepheid. In a recent paper in this journal, Kervella et al. (2008) report a very precise geometric distance to RS Pup, based on measured phase lags of the light variations of individual knots in the reflection nebula. In this commen

J. A. Zurita Heras, S. Chaty

SAX J1818.6-1703 is a flaring transient X-ray source serendipitously discovered by BeppoSAX in 1998 during an observation of the Galactic centre. The source was identified as a High-Mass X-ray Binary with an OB SuperGiant companion. Displaying short and bright flares and an unusually very-low quiescent level implying intensity dynamical range as large as 1e3

Fernando Galve, Eric Lutz

We consider the thermodynamic properties of the squeezed vacuum state of a frequency--modulated quantum harmonic oscillator. We analytically relate the squeezing parameter to the irreversible work and the degree of nonadiabaticity of the frequency transformation. We furthermore determine the optimal modulation that leads to maximal squeezing, and discuss its

P. B. Stetson, E. Pancino

DAOSPEC is a Fortran code for measuring equivalent widths of absorption lines in stellar spectra with minimal human involvement. It works with standard FITS format files and it is designed for use with high resolution (R>15000) and high signal-to-noise-ratio (S/N>30) spectra that have been binned on a linear wavelength scale. First, we review the analysis pr

Fernando Buitrago, Ignacio Trujillo, Christopher J. Conselice

We measure and analyse the sizes of 82 massive (M >= 10^11 M_Sun) galaxies at 1.7<z<3 utilizing deep HST NICMOS data taken in the GOODS North and South fields. Our sample provides the first statistical study of massive galaxy sizes at z>2. We split our sample into disk-like (Sersic index n<=2) and spheroid-like (Sersic index n>2) galaxies, and find that at a

Loic Dubois

In this article, we consider linearly convex complex cones in complex Banach spaces and we define a new projective metric on these cones. Compared to the hyperbolic gauge of Rugh, it has the advantage of being explicit, and easier to estimate. We prove that this metric also satisfies a contraction principle like Birkhoff&#39;s theorem for the Hilbert metric.

Paul Manneville

Contrasting with free shear flows presenting velocity profiles with inflection points which cascade to turbulence in a relatively mild way, wall bounded flows are deprived of (inertial) instability modes at low Reynolds numbers and become turbulent in a much wilder way, most often marked by the coexistence of laminar and turbulent domains at intermediate Rey

J. Yang, L. I. Gurvits, S. Frey, A. P. Lobanov

The upper envelope of the amplitude of the VLBI visibility function usually represents the most compact structural pattern of extragalactic radio sources, in particular, the &#34;core-jet&#34; morphologies. By fitting the envelope to a circular Gaussian model in ~3000 parsec-scale core-jet structures, we find that the apparent angular size shows significant

Steven R. Warren, Andrew A. Cole

Near infrared spectra of 133 red giant stars from ten Galactic open clusters and two Galactic globular clusters spanning 2.2 dex in metallicity and 11 Gyr in age are presented. We combine this sample with ten clusters from Cole and collaborators to investigate the Ca II triplet line strengths and their relation to cluster metallicity and position along the r

Tyler E Keating, Adam T. C. Steege, Arjendu K. Pattanayak

The negativity of a given state&#39;s Wigner function has been proposed as a measure of quantumness of that state in a unipartite system. This otherwise physically intuitive and useful phase-space measure however does not yield the right correspondence principle limit, and also turns out to yield infinite values for the infinite square well. We show that bot

J. A. Mueller, C. S. Fischer

We investigate the chiral phase transition at finite temperatures and zero chemical potential with Dyson-Schwinger equations. Our truncation for the quark-gluon interaction includes mesonic degrees of freedom, which allows us to study the impact of the pions on the nature of the phase transition. Within the present scheme we find a five percent change of the

G. Sciolla, J. Battat, T. Caldwell, B. Cornell

Directional detection of Dark Matter allows for unambiguous direct detection of WIMPs as well as discrimination between various Dark Matter models in our galaxy. The DMTPC detector is a low-pressure TPC with optical readout designed for directional direct detection of WIMPs. By using CF4 gas as the active material, the detector also has excellent sensitivity

S. N. Karpov, Z. M. Karpova, V. A. Bednyakov

The ATLAS detector is intended to verify the standard model and to search for new physics at the Large Hadron Collider (LHC, CERN). In addition to this primary goal, it also allows detection of muons of cosmic rays. On the other hand, unusual bursts of the muon intensity, which correlate with powerful solar flares were recorded and investigated earlier at th

X. F. Wang, T. Wu, G. Wu, R. H. Liu

We study systematically transport, susceptibility and heat capacity for BaFe$_{2-x}$Co$_x$As$_2$ single crystals. In the underdoped region, spin density wave (SDW) transition is observed in both resistivity and susceptibility. The magnetic susceptibility shows unusual T-linear dependence above SDW transition up to 700 K. With Co doping, SDW ordering is gradu

David M. Russell, Dipankar Maitra, Rob P. Fender, Fraser Lewis

Synchrotron emission from jets produced by X-ray binaries can be detected at optical and infrared (IR) frequencies. I show that optical/IR colour-magnitude diagrams of the outbursts of nine X-ray binaries successfully separate thermal disc emission from non-thermal jet emission, in both black hole and neutron star sources. A heated single-temperature blackbo

Ph. Beltrame, P. Hänggi, U. Thiele

Substrate defects crucially influence the onset of sliding drop motion under lateral driving. A finite force is necessary to overcome the pinning influence even of microscale heterogeneities. The depinning dynamics of three-dimensional drops is studied for hydrophilic and hydrophobic wettability defects using a long-wave evolution equation for the film thick

Vladimir Krouglov

In the paper we prove that every closed orientable three-manifold admits a parabolic foliation.

F. A. Zwanenburg, C. E. W. M. van Rijmenam, Y. Fang, C. M. Lieber

We report measurements on a silicon nanowire quantum dot with a clarity that allows for a complete understanding of the spin states of the first four holes. First, we show control of the hole number down to one. Detailed measurements at perpendicular magnetic fields reveal the Zeeman splitting of a single hole in silicon. We are able to determine the ground-

J. Lefebvre, M. Hilke, Z. Altounian, K. W. West

We report on magnetization measurements performed on a series of Fe$_{x}$Ni$_{1-x}$Zr$_{2}$ superconducting metallic glasses with $0\leq x\leq0.5$ using the Hall effect of a nearby 2-dimensional electron gas (2DEG) in a GaAs/Al$_{0.33}$Ga$_{0.67}$As heterostructure as a local probe. The great sensitivity of the Hall effect of the 2DEG in such heterostructure

Nils Lavesson, Leif Lonnblad

We extend earlier schemes for merging tree-level matrix elements with parton showers to include also merging with one-loop matrix elements. In this paper we make a first study on how to include one-loop corrections, not only for events with a given jet multiplicity, but simultaneously for several different jet multiplicities. Results are presented for the si

A. V. Gladyshev, D. I. Kazakov, M. G. Paucar

We analyse the possibility to get light long-lived charginos within the framework of the MSSM with gravity mediated SUSY breaking. We find out that this possibility can be realized in the so-called focus-point region of parameter space. The mass degeneracy of higgsino-like chargino and two higgsino-like neutralinos is the necessary condition for a long lifet

Yveline Lebreton, Josefina Montalban

Asteroseismology provides powerful means to probe stellar interiors. The oscillations frequencies are closely related to stellar interior properties via the density and sound speed profiles. Since these are tightly linked with the mass and evolutionary state, we can expect to determine the age and mass of a star from the comparison of its oscillation spectru

Xinhua Peng, Jingfu Zhang, Jiangfeng Du, Dieter Suter

Local or nonlocal character of quantum states can be quantified and is subject to various bounds that can be formulated as complementarity relations. Here, we investigate the local vs. nonlocal character of pure three-qubit states by a four-way interferometer. The complete entanglement in the system can be measured as the entanglement of a specific qubit wit

M. Castro, S. Vauclair, O. Richard, N. C. Santos

Aims. Exoplanet-host stars (EHS) are known to present superficial chemical abundances different from those of stars without any detected planet (NEHS). EHS are, on the average, overmetallic compared to the Sun. The observations also show that, for cool stars, lithium is more depleted in EHS than in NEHS. The aim of this paper is to obtain constraints on poss

W. L. Yang, H. Wei, F. Zhou, W. L. Chang

The main idea in the original Grover search (Phys. Rev. Lett. 79, 325 (1997)) is to single out a target state containing the solution to a search problem by amplifying the amplitude of the state, following the Oracle&#39;s job, i.e., a black box giving us information about the target state. We design quantum circuits to accomplish a complete Grover search in

Rasmus Pagh, S. Srinivasa Rao

Let S be a finite, ordered alphabet, and let x = x_1 x_2 ... x_n be a string over S. A &#34;secondary index&#34; for x answers alphabet range queries of the form: Given a range [a_l,a_r] over S, return the set I_{[a_l;a_r]} = {i |x_i \in [a_l; a_r]}. Secondary indexes are heavily used in relational databases and scientific data analysis. It is well-known tha

S. A. Corder, K. Sheth, N. Z. Scoville, J. Koda

Spiral arm spurs are prominent features that have been observed in extinction and 8$μ$m emission in nearby galaxies. In order to understand their molecular gas properties, we used the Owens Valley Radio Observatory to map the CO(J=1--0) emission in three spurs emanating from the inner northwestern spiral arm of M51. We report CO detections from all three spu

M. Schultheis, K. Sellgren, S. Ramirez, S. Stolovy

We use the Spitzer IRAC catalogue of the Galactic Center (GC) point sources (Ramirez et al. 2008) and combine it with new isochrones (Marigo et al. 2008) to derive extinctions based on photometry of red giants and asymptotic giant branch (AGB) stars. This new extinction map extends to much higher values of Av than previoulsy available. Our new extinction map

M. Goryca, T. Kazimierczuk, M. Nawrocki, A. Golnik

A system of two coupled CdTe quantum dots, one of them containing a single Mn ion, was studied in continuous wave and modulated photoluminescence, photoluminescence excitation, and photon correlation experiments. Optical writing of information in the spin state of the Mn ion has been demonstrated, using orientation of the Mn spin by spin-polarized carriers t

B. J. Mochejska, K. Z. Stanek, D. D. Sasselov, A. H. Szentgyorgyi

We have undertaken a long-term project, Planets in Stellar Clusters Extensive Search (PISCES), to search for transiting planets in open clusters. In this paper we present the results for NGC 188, an old, rather populous cluster. We have monitored the cluster for more than 87 hours, spread over 45 nights. We have not detected any good transiting planet candid

Arno Fehm

Pop proved that a smooth curve C over an ample field K that has a K-rational point has |K| many K-rational points. We strengthen this result by showing that there are |K| many K-rational points that do not lie in a given proper subfield, even after applying a rational map. As a consequence we gain insight into the structure of existentially definable subsets

R. Fiore, V. R. Zoller

In the neutrino DIS diffraction the charged current non-conservation gives rise to sizable corrections to the longitudinal structure function, $F_L$. These corrections is a higher twist effect enhanced at small-$x$ by the rapidly growing gluon density. The phenomenon manifests itself in abundant production of charm and strangeness by longitudinally polarized

Eric Shellef

We show the critical density for activated random walks on Euclidean lattices is at most one.

Carlos Escudero

We introduce a new equation describing epitaxial growth processes. This equation is derived from a simple variational geometric principle and it has a straightforward interpretation in terms of continuum and microscopic physics. It is also able to reproduce the critical behavior already observed, mound formation and mass conservation, but however does not fi

Basile Graf

We give a simple and self contained introduction to quaternions and their practical usage in dynamics. The rigid body dynamics are presented in full details. In the appendix, some more exotic relations are given that allow to write more complex models, for instance, the one of a satellite with inertial wheels and expressed in a non-inertial reference frame.

Wim de Boer, Jochen Ebert

Silicon trackers at the SLHC will suffer high radiation damage from particles produced during the collisions, which leads to high leakage currents. Reducing these currents in the sensors requires efficient cooling to -30 C. The large heat of evaporation of CO2 and the low viscosity allows for a two-phase cooling system with thin and long cooling pipes, becau

V. Togo, I. Traore&#39;

We developed a new method for determining the bulk etch rate velocity based on both cone height and base diameter measurements of the etched tracks. This method is applied here for the calibration of CR39 and Makrofol nuclear track detectors exposed to 158 A GeV In^{49+} and Pb^{82+} ions, respectively. For CR39 the peaks corresponding to indium ions and the

Gregory P. Lousberg, Marcel Ausloos, Christophe Geuzaine, Patrick Dular

We make progress towards a 3D finite-element model for the magnetization of a high temperature superconductor (HTS): We suggest a method that takes into account demagnetisation effects and flux creep, while it neglects the effects associated with currents that are not perpendicular to the local magnetic induction. We consider samples that are subjected to a

M. Di Toro, V. Baran, M. Colonna, G. Ferini

Heavy Ion Collisions (HIC) represent a unique tool to probe the in-medium nuclear interaction in regions away from saturation. In this report we present a selection of new reaction observables in dissipative collisions particularly sensitive to the symmetry term of the nuclear Equation of State (Iso-EoS). We will first discuss the Isospin Equilibration Dynam

Pietro Giudice, Ferdinando Gliozzi, Stefano Lottini

The random percolation model can be viewed as the dual of a well defined confining gauge theory; since this theory, having no Monte Carlo dynamics at all, is simple to simulate, it is possible to study the properties of the flux tube with very high precision; we show it can be described by the effective string picture. Our results are lattice regularisation

Carlo Nipoti, Pasquale Londrillo, Luca Ciotti

We describe some results obtained with N-MODY, a code for N-body simulations of collisionless stellar systems in modified Newtonian dynamics (MOND). We found that a few fundamental dynamical processes are profoundly different in MOND and in Newtonian gravity with dark matter. In particular, violent relaxation, phase mixing and galaxy merging take significant

G. W. Gibbons, C. A. R. Herdeiro, C. M. Warnick, M. C. Werner

We consider a triality between the Zermelo navigation problem, the geodesic flow on a Finslerian geometry of Randers type, and spacetimes in one dimension higher admitting a timelike conformal Killing vector field. From the latter viewpoint, the data of the Zermelo problem are encoded in a (conformally) Painleve-Gullstrand form of the spacetime metric, where

Orfeu Bertolami, Tiberiu Harko, Francisco S. N. Lobo, Jorge Páramos

Recently, in the context of f(R) modified theories of gravity, it was shown that a curvature-matter coupling induces a non-vanishing covariant derivative of the energy-momentum, implying non-geodesic motion and, under appropriate conditions, leading to the appearance of an extra force. We study the implications of this proposal and discuss some directions fo

Nicolas Crouseilles, Thomas Respaud, Eric Sonnendrücker

This work deals with the numerical solution of the Vlasov equation. This equation gives a kinetic description of the evolution of a plasma, and is coupled with Poisson&#39;s equation for the computation of the self-consistent electric field. The coupled model is non linear. A new semi-Lagrangian method, based on forward integration of the characteristics, is

Mariusz Puchalski, Krzysztof Pachucki

Accurate results for nonrelativistic energy, relativistic, QED, and finite nuclear mass corrections are obtained for $2^1S_{1/2}$, $3^1S_{1/2}$ and $2^1P_{1/2}$ states of the Li atom and Be$^+$ ion. Our computational approach uses the Hylleraas basis set with the analytic integration and recursion relations. From comparison of experimental results for the is

Pekka Alitalo, Frederic Bongard, Jean-Francois Zurcher, Juan Mosig

Cloaking using a volumetric structure composed of stacked two-dimensional transmission-line networks is verified with measurements. The measurements are done in a waveguide, in which an array of metallic cylinders is inserted causing a short-circuit in the waveguide. The metal cylinders are cloaked using a previously designed and simulated cloak that hides t

Shin-ichi Kimura, Takuya Iizuka, Yong-seung Kwon

We have demonstrated that the middle-infrared (mid-IR) peaks in the optical conductivity spectra of Ce$X_3$ ($X$ = Pd, Sn, In) can be explained by first-principle band structure calculation with the spin-orbit interaction. The mid-IR peak shapes in these materials are not identical to one another: CePd$_3$, CeSn$_3$, and CeIn$_3$ have a triple-peak structure

Hamed Firouzi, Masoud Farivar, Massoud Babaie-Zadeh, Christian Jutten

In this paper, we propose a method to address the problem of source estimation for Sparse Component Analysis (SCA) in the presence of additive noise. Our method is a generalization of a recently proposed method (SL0), which has the advantage of directly minimizing the L0-norm instead of L1-norm, while being very fast. SL0 is based on minimization of the smoo

Mitsunobu Kawada, Hidenori Takahashi, Noriko Murakami, Hiroshi Matsuo

We have developed an imaging Fourier transform spectrometer (FTS) for space-based far-infrared astronomical observations. The FTS employs a newly developed photoconductive detector arrays with a capacitive trans-impedance amplifier, which makes the FTS a completely unique instrument. The FTS was installed as a function of the far-infrared instrument (FIS: Fa

Luca Callegaro, Marco Pisani, Alessio Pollarolo

A field-effect transistor (FET) amplifier for small voltage signals is presented. Its design is elementary and the construction can be afforded by anyone. Despite its simplicity, with a voltage noise less than 1 nV/sqrt(Hz), it outperforms commercially available integrated FET amplifiers. The amplifier has a gain flatness better than 1 dB over 1 MHz bandwidt

V. Mironov, J. P. M. Beijers

The ion production in an ECRIS is modelled using a particle-in-cell Monte-Carlo collision code in a three-dimensional geometry. Only the heavy particles (ions and atoms) are tracked, with the electron density determined from the requirement of quasi-neutrality, and the electron temperature is a free parameter. The electric fields in the plasma are assumed to

Janus Collaboration, F. Belletti, A. Cruz, L. A. Fernandez

Using the dedicated computer Janus, we follow the nonequilibrium dynamics of the Ising spin glass in three dimensions for eleven orders of magnitude. The use of integral estimators for the coherence and correlation lengths allows us to study dynamic heterogeneities and the presence of a replicon mode and to obtain safe bounds on the Edwards-Anderson order pa

Constantinos Kalapotharakos, Ioannis Contopoulos

We investigate the three-dimensional structure of the pulsar magnetosphere through time-dependent numerical simulations of a magnetic dipole that is set in rotation. We developed our own Eulerian finite difference time domain numerical solver of force-free electrodynamics and implemented the technique of non-reflecting and absorbing outer boundaries. This al

Federico Laudisa

According to a widespread view, the Bell theorem establishes the untenability of so-called &#39;local realism&#39;. On the basis of this view, recent proposals by Leggett, Zeilinger and others have been developed according to which it can be proved that even some non-local realistic theories have to be ruled out. As a consequence, within this view the Bell t

R. Hänninen, W. Schoepe

The critical velocity vc for the onset of turbulent drag of small spheres oscillating in superfluid 4He is frequency dependent (omega/2pi from 100 Hz to 700 Hz) and is described by vc = 2.6sqrt(kappa*omega), where kappa is the circulation quantum. A qualitative analysis based on a recent theory of the onset of superfluid turbulence gives vc = sqrt(8*kappa*om

M. B. N. Kouwenhoven, A. G. A. Brown, S. P. Goodwin, S. F. Portegies Zwart

Knowledge of the binary population in stellar groupings provides important information about the outcome of the star forming process in different environments (see, e.g., Blaauw 1991, and references therein). Binarity is also a key ingredient in stellar population studies, and is a prerequisite to calibrate the binary evolution channels. In this paper we pre

Sergio-Andres Galindo-Torres, Fernando Alonso-Marroquin

The Minkowski operators (addition and substraction of sets in vectorial spaces) has been extensively used for Computer Graphics and Image Processing to represent complex shapes. Here we propose to apply those mathematical concepts to extend the Molecular Dynamics (MD) Methods for simulations with complex-shaped particles. A new concept of Voronoi-Minkowski d

S. Anderloni, F. Benatti, R. Floreanini, G. G. Guerreschi

We study the dynamics of ultracold atoms trapped in optical double-well potentials in presence of noise generated by an external environment. When prepared in a Fock number state, the system shows phase coherence in the averaged density profile obtained using standard absorption image techniques, that disappears in absence of noise. This effect indicates tha

J. Messud, P. M. Dinh, P. -G. Reinhard, E. Suraud

We present a new formulation of the time-dependent self-interaction correction (TDSIC). It is derived variationally obeying explicitly the constraints on orthonormality of the occupied single-particle orbitals. The thus emerging rather involved symmetry condition amongst the orbitals is dealt with using two separate sets of (occupied) single-particle wavefun

Frederic Bernicot

In this work, some non smooth bilinear analogues of linear Littlewood-Paley square functions on the real line are studied. These bilinear operators are closely related to the bilinear Hilbert transforms and vector valued version of these ones. Mainly we prove boundedness-properties in Lebesgue spaces for them.

Bikash Kumar Dey, Sidharth Jaggi, Michael Langberg

In this work we consider the communication of information in the presence of an online adversarial jammer. In the setting under study, a sender wishes to communicate a message to a receiver by transmitting a codeword x=x_1,...,x_n symbol-by-symbol over a communication channel. The adversarial jammer can view the transmitted symbols x_i one at a time, and can

Francis Filbet, Clément Mouhot

The development of accurate and fast algorithms for the Boltzmann collision integral and their analysis represent a challenging problem in scientific computing and numerical analysis. Recently, several works were devoted to the derivation of spectrally accurate schemes for the Boltzmann equation, but very few of them were concerned with the stability analysi

Ashish V. Orpe, V. Kumaran, K. Anki Reddy, Arshad Kudrolli

We find in complementary experiments and event driven simulations of sheared inelastic hard spheres that the velocity autocorrelation function $ψ(t)$ decays much faster than $t^{-3/2}$ obtained for a fluid of elastic spheres at equilibrium. Particle displacements are measured in experiments inside a gravity driven flow sheared by a rough wall. The average pa

Hemant Ishwaran, Udaya B. Kogalur

We prove uniform consistency of Random Survival Forests (RSF), a newly introduced forest ensemble learner for analysis of right-censored survival data. Consistency is proven under general splitting rules, bootstrapping, and random selection of variables--that is, under true implementation of the methodology. A key assumption made is that all variables are fa

Steven P. Ellis

A descent algorithm, &#34;Quasi-Quadratic Minimization with Memory&#34; (QQMM), is proposed for unconstrained minimization of the sum, $F$, of a non-negative convex function, $V$, and a quadratic form. Such problems come up in regularized estimation in machine learning and statistics. In addition to values of $F$, QQMM requires the (sub)gradient of $V$. Two