April 2009 arXiv papers — page 10

Zhenning Kong, Salah A. Aly, Emina Soljanin

We consider large-scale wireless sensor networks with $n$ nodes, out of which k are in possession, (e.g., have sensed or collected in some other way) k information packets. In the scenarios in which network nodes are vulnerable because of, for example, limited energy or a hostile environment, it is desirable to disseminate the acquired information throughout

Philippe Pebay, J. Maurice Rojas, David C. Thompson

We give a high precision polynomial-time approximation scheme for the supremum of any honest n-variate (n+2)-nomial with a constant term, allowing real exponents as well as real coefficients. Our complexity bounds count field operations and inequality checks, and are polynomial in n and the logarithm of a certain condition number. For the special case of pol

G. Anetsberger, O. Arcizet, Q. P. Unterreithmeier, R. Rivière

Cavity-enhanced radiation pressure coupling between optical and mechanical degrees of freedom allows quantum-limited position measurements and gives rise to dynamical backaction enabling amplification and cooling of mechanical motion. Here we demonstrate purely dispersive coupling of high Q nanomechanical oscillators to an ultra-high finesse optical microres

Lucas Goehring

Starch-water slurries are commonly used to study fracture dynamics. Drying starch-cakes benefit from being simple, economical, and reproducible systems, and have been used to model desiccation fracture in soils, thin film fracture in paint, and columnar joints in lava. In this paper, the physical properties of starch-water mixtures are studied, and used to i

James Graber

This paper computes co-rotating and contra-rotating impact-parameter formulas in the plane of symmetry for any plane symmetric and axisymmetric rotating body in all metric theories of gravity, including general relativity. Impact-parameter formulas are useful to compute the appearance of accreting black holes, neutron stars, and other emitting or reflecting

Graeme Smith, John A. Smolin

Quantum information theory establishes the ultimate limits on communication and cryptography in terms of channel capacities for various types of information. The private capacity is particularly important because it quantifies achievable rates of quantum key distribution. We study the power of quantum channels with limited private capacity, focusing on chann

Deog Ki Hong, Doyoun Kim

We have performed a holographic calculation of the hadronic contributions to the anomalous magnetic moment of the muon, using the gauge/gravity duality. We study a model of holographic QCD in the five dimensional AdS background with a hard-wall cutoff. Both 5D SU(2) and U(3) flavor gauge symmetries are considered for the neutral pion, eta and eta' contri

Lucia Caporaso, Filippo Viviani

We study the Torelli morphism from the moduli space of stable curves to the moduli space of principally polarized stable semi-abelic pairs. We give two characterizations of its fibers, describe its injectivity locus, and give a sharp upper bound on the cardinality of the finite fibers. We also bound the dimension of the infinite fibers. In particular, we obt

Karthik H. Shankar, Kameshwar C. Wali

Here we consider a variant of the 5 dimensional Kaluza-Klein theory within the framework of Einstein-Cartan formalism that includes torsion. By imposing a set of constraints on torsion and Ricci rotation coefficients, we show that the torsion components are completely expressed in terms of the metric. Moreover, the Ricci tensor in 5D corresponds exactly to w

Attilio Cucchieri, Tereza Mendes

We study Landau-gauge gluon and ghost propagators in Yang-Mills theories at lattice parameter beta = 0, considering relatively large lattice volumes for the case of the SU(2) gauge group in three and four space-time dimensions. We compare the lattice data to the so-called massive and conformal-scaling solutions, examining the requirements for a good descript

Yufeng Mao, Jing Wang, Jianyan Wei

We introduce a new physical parameter, the optical variability amplitude, to the well-established Eigenvector 1 space of quasars and test a sample of long-term B-band light curves of 42 PG quasars monitored by Giveon et al. (1999). We find that the optical variability amplitude strongly correlates with the intensity ratio of Fe II to H$β$, H$β$ width and pea

S. Salimi, A. Sorouri

In this paper we present a model exhibiting a new type of continuous-time quantum walk (as a quantum mechanical transport process) on networks, which is described by a non-Hermitian Hamiltonian possessing a real spectrum. We call it pseudo-Hermitian continuous-time quantum walk. We introduce a method to obtain the probability distribution of walk on any vert

Alain Miranville, Sergey Zelik

Our aim in this paper is to study the Cahn-Hilliard equation with singular potentials and dynamic boundary conditions. In particular, we prove, owing to proper approximations of the singular potential and a suitable notion of variational solutions, the existence and uniqueness of solutions. We also discuss the separation of the solutions from the singulariti

Y. Zhang, F. Chen, C. He, B. Zhou

The unconventional superconductivity in the newly discovered iron-based superconductors is intimately related to its multi-band/multi-orbital nature. Here we report the comprehensive orbital characters of the low-energy three-dimensional electronic structure in BaFe$_{1.85}$Co$_{0.15}$As$_2$ by studying the polarization and photon energy dependence of angle-

Marine Guigou, Thierry Martin, Adeline Crépieux

The screening effect due to a scanning tunneling microscope tip which is placed in the vicinity of an interacting quantum wire is considered. With the help of a bosonization procedure, we are able to determine non perturbatively the Green's functions of the quantum wire in the presence of both electrostatic screening by the tip and Coulomb interactions i

R. de la Fuente Marcos, C. de la Fuente Marcos

Observations indicate that the fraction of potential binary star clusters in the Magellanic Clouds is about 10%. In contrast, it is widely accepted that the binary cluster frequency in the Galaxy disk is much lower. Here we investigate the multiplicity of clusters in the Milky Way disk to either confirm or disprove this dearth of binaries. We quantify the op

Juan José Hernández-Rey

The observation of high energy extraterrestrial neutrinos can be an invaluable source of information about the most energetic phenomena in the Universe. Neutrinos can shed light on the processes that accelerate charge particles in an incredibly wide range of energies both within and outside our Galaxy. They can also help to investigate the nature of the dark

Yongquan Hu

Let $p$ be a prime number and $F$ a local field with residual characteristic $p$. In this article, to an irreducible smooth representation of $GL_2(F)$ over $\bar{\mathbf{F}}_p$ with central character, we associate canonically a diagram which determines the original representation up to isomorphism. We also determine it in some cases.

Avraham Gal

Selected topics in Strangeness Nuclear Physics are reviewed: Lambda-hypernuclear spectroscopy and structure, Sigma-hyperon nuclear interaction, multistrangeness, and anti-kaons in nuclei.

Chan-Gyung Park, Jai-chan Hwang, Jae-heon Lee, Hyerim Noh

We show the importance of properly including the perturbations of the dark energy component in the dynamical dark energy models based on a scalar field and modified gravity theories in order to meet with present and future observational precisions. Based on a simple scaling scalar field dark energy model, we show that observationally distinguishable substant

Nathan Moore, Nicole Schoolmeesters

The paper describes two general problems encountered in computational assignments at the introductory level. First, novice students often treat computer code as almost magic incantations, and like novices in many fields, have trouble creating new algorithms or procedures to solve novel problems. Second, the nature of computational studies often means that th

Ingunn Kathrine Wehus, Lotty Ackerman, H. K. Eriksen, Nicolaas E. Groeneboom

We generate simulations of the CMB temperature field as observed by the WMAP satellite, taking into account the detailed shape of the asymmetric beams and scanning strategy of the experiment, and use these to re-estimate the WMAP beam transfer functions. This method avoids the need of artificially symmetrizing the beams, as done in the baseline WMAP approach

Naoto Nagaosa, Jairo Sinova, Shigeki Onoda, A. H. MacDonald

We present a review of experimental and theoretical studies of the anomalous Hall effect (AHE), focusing on recent developments that have provided a more complete framework for understanding this subtle phenomenon and have, in many instances, replaced controversy by clarity. Synergy between experimental and theoretical work, both playing a crucial role, has

Bai-Qing Li, Ce Meng, Kuang-Ta Chao

Using the same quenched limit as input, we compare the charmonium spectra predicted by the coupled-channel model and the screened potential model in the mass region below 4 GeV, in which the contributions from decay channels involving P-wave (as well as even higher excited) D mesons can be neglected. We find that the two models have similar global features i

H. Kusumaatmaja, J. M. Yeomans

We consider the equilibrium behaviour and dynamics of liquid drops on a superhydrophobic surface patterned with sawtooth ridges or posts. Due to the anisotropic geometry of the surface patterning, the contact line can preferentially depin from one side of the ratchets, leading to a novel, partially suspended, superhydrophobic state. In both this configuratio

The BABAR Collaboration, B. Aubert

We present a measurement of the Cabibbo-Kobayashi-Maskawa matrix element |V_cb| and the form-factor slope rho^2 in Bbar -> Dl- nubar decays based on 460 million BBar events recorded at the Upsilon(4S) resonance with the BaBar detector. BBar -> Dl- nubar decays are selected in events in which a hadronic decay of the second B meson is fully reconstructed. We m

Dennis Eriksson

This is the first article in an upcoming series of papers. They have arisen through an attempt to answer open questions of Deligne proposed in "Le determinant de la cohomologie", Contemp. Mathematics 67 (1987). It amounts to functorial and metrized versions of the Grothendieck-Riemann-Roch theorem, as well as a Lefschetz-Riemann-Roch formula in the s

Jeff Arnold, Tim Abbott, Waseem Daher, Gregory Price

In this paper, we question the common practice of assigning security impact ratings to OS updates. Specifically, we present evidence that ranking updates by their perceived security importance, in order to defer applying some updates, exposes systems to significant risk. We argue that OS vendors and security groups should not focus on security updates to the

Y. N. Zhao, J. Zhang, J. Stuhler, G. Schuricht

We report ultra-stable locking of a commercially available extended cavity diode laser to a vibration-insensitive high finesse Fabry-Perot cavity. A servo bandwidth of 2 MHz is demonstrated. The absolute stability of the diode laser after locking is measured with a three-cornered-hat method. The resulting Allan deviation reaches a level of $2.95\times10^{-15

Joseph D. Gelfand, Patrick O. Slane, Weiqun Zhang

A pulsar wind nebula inside a supernova remnant provides a unique insight into the properties of the central neutron star, the relativistic wind powered by its loss of rotational energy, its progenitor supernova, and the surrounding environment. In this paper, we present a new semi-analytic model for the evolution of such a pulsar wind nebula which couples t

Qiming Lu, Christof Teuscher

The study of the response of complex dynamical social, biological, or technological networks to external perturbations has numerous applications. Random Boolean Networks (RBNs) are commonly used a simple generic model for certain dynamics of complex systems. Traditionally, RBNs are interconnected randomly and without considering any spatial extension and arr

X. G. Luo, M. A. Tanatar, J. -Ph. Reid, H. Shakeripour

The thermal conductivity $κ$ of the iron-arsenide superconductor Ba$_{1-x}$K$_x$Fe$_2$As$_2$ ($T_c \simeq$ 30 K) was measured in single crystals at temperatures down to $T \simeq 50$ mK ($\simeq T_c$/600) and in magnetic fields up to $H = 15$ T ($\simeq H_{c2}$/4). A negligible residual linear term in $κ/T$ as $T \to 0$ shows that there are no zero-energy qu

Saloua Chettibi

Maximizing network lifetime is a very challenging issue in routing protocol design for Mobile Ad-hoc NETworks (MANETs), since mobile nodes are powered by limited-capacity batteries. Furthermore, replacing or recharging batteries is often impossible in critical environments (e.g. battlefields, disaster areas, etc.). Energy consumption was considered for a lon

V. M. Ghertzik

A multicomponent random process used as a model for the problem of space-time earthquake prediction; this allows us to develop consistent estimation for conditional probabilities of large earthquakes if the values of the predictor characterizing the seismicity prehistory are known. We introduce tools for assessing prediction efficiency, including a separate

Beverly J. Smith, Mark Hancock

Dwarf galaxies tend to have redder [3.6 micron] - [4.5 micron] Spitzer broadband colors than spirals. To investigate this effect, for a large sample of dwarf galaxies we combine Spitzer fluxes with data at other wavelengths and compare to population synthesis models. Lower metallicity systems are found to have redder [3.6] - [4.5] colors on average, but with

M. Alvioli C. Ciofi degli Atti, L. P. Kaptari

The cross section and the transverse-longitudinal asymmetry A_{TL} of the three-body-break-up (3BBU) process 3He(e,e'p)pn have been calculated by a non-factorized and parameter-free approach based upon realistic few-body wave functions corresponding to the $AV18$ interaction, treating the rescattering of the struck nucleon within a generalized eikonal approx

Francisco M. Fernández

We show that recent applications of the homotopy perturbation method the Adomian decomposition method and the variational iteration method are completely useless for the treatment of nonlinear problems.

T. Yang, C. Andreopoulos, H. Gallagher, K. Hoffmann

We present a detailed description of a new hadronic multiparticle production model for use in neutrino interaction simulations. Its validity spans a wide invariant mass range starting from pion production threshold. This model focuses on the low invariant mass region which is probed in few-GeV neutrino interactions and is of particular importance to neutrino

Jie Luo, Mario A. Nascimento

The typical content-based image retrieval problem is to find images within a database that are similar to a given query image. This paper presents a solution to a different problem, namely that of content based sub-image retrieval, i.e., finding images from a database that contains another image. Note that this is different from finding a region in a (segmen

Min Huang

We analyze the behavior of the wave function $ψ(x,t)$ for one dimensional time-dependent Hamiltonian $H=-\partial_x^2\pm2δ(x)(1+2r\cosωt)$ where $ψ(x,0)$ is compactly supported. We show that $ψ(x,t)$ has a Borel summable expansion containing finitely many terms of the form $\sum_{n=-\infty}^{\infty} e^{i^{3/2}\sqrt{-λ_{k}+n\omegai}|x|} A_{k,n} e^{-λ_{k}t+nωi

Jayanth R. Banavar, Marek Cieplak, Trinh Xuan Hoang, Amos Maritan

Learning from nature's amazing molecular machines, globular proteins, we present a framework for the predictive design of nano-machines. We show that the crucial ingredients for a chain molecule to behave as a machine are its inherent anisotropy and the coupling between the local Frenet coordinate reference frames of nearby monomers. We demonstrate that,

J. Kowalski-Glikman, A. Walkus

In this note we extend the methods developed by Freidel et al. [arXiv:hep-th/0612170] to derive the form of $ϕ^4$ interaction term in the case of scalar field theory on $κ$-Minkowski space, defined in terms of star product. We present explicit expressions for the $κ$-Minkowski star product. Having obtained the the interaction term we use the resulting deform

Elena V. Kazantseva, Andrei I. Maimistov, Sergei S. Ozhenko

We consider the electromagnetic waves propagating in the system of coupled waveguides. One of the system components is a standard waveguide fabricated from nonlinear medium having positive refraction and another component is a waveguide produced from an artificial material having negative refraction. The metamaterial constituting the second waveguide has lin

Miodrag L. Kulic, Armen Sedrakian, Dirk H. Rischke

A rotating ultracold S-wave superfluid Fermi gas is considered, when the population imbalance (or equivalently the mismatch in chemical potentials) corresponds to the Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) state in the vicinity of the Lifshitz critical point. It is shown that under these conditions the critical angular velocity in two-dimensional systems is

X. Fu, P. Zhang, H. Hu, C. J. Huang

The present study presents a simple but effective method for 3D visualization of the two-phase flow in the micro-tube. An isosceles right-angle prism combined with a mirror located 45^o bevel to the prism is employed to obtain synchronously the front and side views of the flow patterns with a single camera, where the locations of the prism and the micro-tube

Kourosh Nozari, S. Davood Sadatian

We study dynamics of a dark energy component nonminimally coupled to gravity on a moving domain wall. We use this setup to explain late-time accelerated expansion and crossing of the phantom divide line by the equation of state parameter of this non-minimally coupled dark energy component. By analyzing parameter space of the model, we show that this model ac

Andrei Galiautdinov

We propose a scheme for generating SU(2) adiabatic geometric phases in a circuit consisting of three capacitively coupled flux-biased Josephson phase qubits.

Senlin Guo, Feng Qi

In this article, a necessary and sufficient condition and a necessary condition are established for a function involving the gamma function to be logarithmically completely monotonic on $(0,\infty)$. As applications of the necessary and sufficient condition, some inequalities for bounding the psi and polygamma functions and the ratio of two gamma functions a

Ying Fan, Yan-Qing Ma, Kuang-Ta Chao

Relativistic corrections to the color-singlet J/ψhadroproduction at the Tevatron and LHC are calculated up to O(v^2) in nonrelativistic QCD (NRQCD). The short distance coefficients are obtained by matching full QCD with NRQCD results for the subprocess g+g\to J/ψ+g. The long distance matrix elements are extracted from observed J/ψhadronic and leptonic decay

Sanjiv Kumar Tiwari, Jayant Joshi, Sanjay Gosain, P. Venkatakrishnan

We have studied the evolution of magnetic helicity and chirality in an active region over three consecutive solar rotations. The region when it first appeared was named NOAA10923 and in subsequent rotations it was numbered NOAA 10930, 10935 and 10941. We compare the chirality of these regions at photospheric, chromospheric and coronal heights. The observatio

Wenzhuo Zhang

The wave-particle duality of the vacuum states of quantum fields is considered and the particle-like property of the vacuum state of a quantum field is proposed as a vacuum-particle which carries the vacuum-energy and the vacuum-momentum of this field. The vacuum-particles can be introduced into the quantum field theory (QFT) naturally without disturbing its

M. Feng, Y. Y. Xu, F. Zhou, D. Suter

Physical systems must fulfill a number of conditions to qualify as useful quantum bits (qubits) for quantum information processing, including ease of manipulation, long decoherence times, and high fidelity readout operations. Since these conditions are hard to satisfy with a single system, it may be necessary to combine different degrees of freedom. Here we

Yoko Miura, Masatoshi Sato, Youichi Yamakawa, Tatsuro Habaguchi

A pseudo honeycomb system Li2RuO3 exhibits a second-order-like transition at temperature T=Tc=540 K to a low-T nonmagnetic phase with a significant lattice distortion forming Ru-Ru pairs. For this system, we have calculated the band structure, using the generalized gradient approximation (GGA) in both the high- and low- T phases, and found that the results o

Yoshiaki Kobayashi, Kenji Sato, Yukio Yasui, Taketo Moyoshi

Neutron diffraction and 7Li-NMR have been applied to determine the multiferroic system LiCu2O2, which has four chains (ribbon chains) of edge-sharing CuO4 square planes in a unit cell. We have confirmed that there are successive magnetic transitions at TN1=24.5 K and TN2=22.8 K. In the T region between TN1 and TN2, the quasi one-dimensional spins (S=1/2) of

A. Paglietti

The standard theory of ideal gases ignores the interaction of the gas particles with the thermal radiation (photon gas) that fills the otherwise vacuum space between them. This is an unphysical feature of the theory since every material in this universe, and hence also the particles of a gas, absorbs and radiates thermal energy. The interaction with the ther

Yukio Yasui, Kenji Sato, Yoshiaki Kobayashi, Masatoshi Sato

Single-crystal samples of LiCu2O2 with spin 1/2 Cu2+ chains of edge-sharing CuO4 square planes (ribbon chains), have been characterized by X-ray diffraction, thermogravimetric analysis, and magnetic measurements. Neither the atomic deficiency nor the mixing of Cu and Li atoms has been found, indicating that lattice defects conceived as a possible origin of t

Najib Mahdou, Mohammed Tamekkante

This paper generalize the idea of the authors in \cite{Bennis and Mahdou1}. Namely, we define and study a particular case of modules with Gorenstein projective, injective, and flat dimension less or equal than $n\geq 0$, which we call, respectively, strongly n-Gorenstein projective, injective and flat modules. These three classes of modules give us a new cha

Ryuzo Torii

We extend Jendrol' and Skupień's results about the local structure of maps on the 2-sphere: In this paper we show that if a polyhedral map $G$ on a surface $\M$ of Euler characteristic $χ(\M) \le 0$ has more than $126|χ(\M)|$ vertices, then $G$ has a vertex with "nearly" non-negative combinatorial curvature. As a corollary of this, we can ded

B. Eslami-Mossallam, M. R. Ejtehadi

In this paper we consider the anharmonic corrections to the anisotropic elastic rod model for DNA. Our model accounts for the difference between the bending energies of positive and negative rolls, which comes from the asymmetric structure of the DNA molecule. We will show that the model can explain the high flexibility of DNA at small length scales, as well

R. Rajesh, Vinod Sharma, V. K. Varshenya

We consider the problem of transmission of several distributed correlated sources over a multiple access channel (MAC) with side information at the sources and the decoder. Source-channel separation does not hold for this channel. Sufficient conditions are provided for transmission of sources with a given distortion. The source and/or the channel could have

Bau-Sen Du

Let $n \ge 3$ be an integer. Let $P_n = \{1, 2, 3, ..., n-1, n \}$ and let $S_n$ be the symmetric group of permutations on $P_n$. Motivated by the theory of discrete dynamical systems on the interval, we associate each permutation $\si_n$ in $S_n$ a (zero-one) Petrie matrix $M_{\si_n,n-1}$ in $GL(n-1,{\mathbb{R}})$ (which is generally not the same as the usu

Boris Plotkin

The paper is essentially a continuation of B.Plotkin, G.Zhitomirski, "Some logical invariants of algebras and logical relations between algebras", St.Peterburg Math. J., {19:5}, (2008) 859 -- 879, whose main notion is that of logic-geometrical equivalence of algebras (LG-equivalence of algebras). This equivalence of algebras is more strict than eleme

Abhishek Saha

Let F be a genus two Siegel newform and g a classical newform, both of squarefree levels and of equal weight l. We prove a pullback formula for certain Eisenstein series -- thus generalizing a construction of Shimura -- and use this to derive an explicit integral representation for the degree eight L-function L(s, F X g). This integral representation involve

N. Andruskiewitsch, F. Fantino, M. Graña, L. Vendramin

This is a sequel to arXiv:0807.2406. It is shown that the Nichols algebras over the symmetric groups S_m, m > 4, are all infinite-dimensional, except (maybe) those related to the transpositions considered by Fomin and Kirillov, resp. Milinski and Schneider, and the class of type (2,3) in S_5.

Luchezar L. Avramov, Srikanth B. Iyengar, Joseph Lipman, Suresh Nayak

We study functors underlying derived Hochschild cohomology, also called Shukla cohomology, of a commutative algebra S essentially of finite type and of finite flat dimension over a commutative noetherian ring K. We construct a complex of S-modules D, and natural reduction isomorphisms Ext^*_{S\otimes^L_{K}S}(S|K;M\otimes^L_{K}N) ~ Ext^*_S(RHom_S(M,D),N) for

Yu Hin Au

We show that for every $n \geq 1$ and over any finite alphabet, there is a word whose circular factors of length $n$ have a one-to-one correspondence with the set of primitive words. In particular, we prove that such a word can be obtained by a greedy algorithm, or by concatenating all Lyndon words of length $n$ in increasing lexicographic order. We also loo

Albert Fannjiang, Pengchong Yan, Thomas Strohmer

The linear inverse source and scattering problems are studied from the perspective of compressed sensing, in particular the idea that sufficient incoherence and sparsity guarantee uniqueness of the solution. By introducing the sensor as well as target ensembles, the maximum number of recoverable targets is proved to be at least proportional to the number of

Robert Balawender, Andrzej Holas

The formalism developed in the first paper of the series [arXiv:0901.1060] is applied to two thermodynamic systems: (i) of three global observables (the energy, the total electron number and the spin number), (ii) of one global observable (the internal electron energy) and two local (position-dependent) observables (the total electron density and the spin de

Shoichi Fujimori, Wayne Rossman

We show existence of constant mean curvature 1 surfaces in both hyperbolic 3-space and de Sitter 3-space with two complete embedded ends and any positive genus up to genus twenty. We also find another such family of surfaces in de Sitter 3-space, but with a different non-embedded end behavior.

Andrey E. Miroshnichenko, Yuri S. Kivshar

We introduce a concept of the Mach-Zehnder-Fano interferometer by inserting a cavity exhibiting Fano resonance into a conventional interferometer. By employing the scattering-matrix approach, we demonstrate that the transmission is sensitive to a position of the cavity such that an asymmetric structure exhibits a series of narrow resonances with almost perfe

Keivan Borna, Sean Sather-Wagstaff, Siamak Yassemi

Let R be a local Cohen-Macaulay ring with canonical module ω_R. We investigate the following question of Huneke: If the sequence of Betti numbers \{β_i^R(ω_R)\} has polynomial growth, must R be Gorenstein? This question is well-understood when R has minimal multiplicity. We investigate this question for a more general class of rings which we say are homologi

Hossein Hajiabolhassan

In this note, we prove that for any integer $n\geq 3$ the b-chromatic number of the Kneser graph $KG(m,n)$ is greater than or equal to $2{\lfloor {m\over 2} \rfloor \choose n}$. This gives an affirmative answer to a conjecture of [6].

H. T. Intema, S. van der Tol, W. D. Cotton, A. S. Cohen

Calibration of radio interferometric observations becomes increasingly difficult towards lower frequencies. Below ~300 MHz, spatially variant refractions and propagation delays of radio waves traveling through the ionosphere cause phase rotations that can vary significantly with time, viewing direction and antenna location. In this article we present a descr

Olivier Debarre, Claire Voisin

We construct a new 20-dimensional family of algebraic hyper-Kaehler fourfolds and prove that they are deformation-equivalent to the second punctual Hilbert scheme of a K3 surface of degree 22.

Roland Zimmermann, Christoph Schindler

The coherent potential approximation (CPA) is extended to describe satisfactorily the motion of particles in a random potential which is spatially correlated and smoothly varying. In contrast to existing cluster-CPA methods, the present scheme preserves the simplicity of the conventional CPA in using a single self-energy function. Its accuracy is checked by

Dominik R. G. Schleicher, Daniele Galli, Simon C. O. Glover, Robi Banerjee

We explore the effects of magnetic energy dissipation on the formation of the first stars. For this purpose, we follow the evolution of primordial chemistry in the presence of magnetic fields in the post-recombination universe until the formation of the first virialized halos. From the point of virialization, we follow the protostellar collapse up to densiti

A. Barletta

A thermodynamic argument is proposed in order to discuss the most appropriate form of the local energy balance equation within the Oberbeck-Boussinesq approximation. The study is devoted to establish the correct thermodynamic property to be used in order to express the relationship between the change of internal energy and the temperature change. It is noted

Marek Biskup, Roberto H. Schonmann

We examine bootstrap percolation on a regular (b+1)-ary tree with initial law given by Bernoulli(p). The sites are updated according to the usual rule: a vacant site becomes occupied if it has at least theta occupied neighbors, occupied sites remain occupied forever. It is known that, when b>theta>1, the limiting density q=q(p) of occupied sites exhibits a j

Raymond Y. Chiao

"Millikan oil drops" are drops of superfluid helium coated with electrons, and levitated in a strong, inhomogeneous magnetic field. When the temperature of the system becomes very low compared to the cyclotron gap energy, the system remains in its quantum ground state. Two such levitated charged drops can have their charge-to-mass ratio critically ad

Sangjib Kim

We study the nullcone in the multi-vector representation of the symplectic group with respect to a joint action of the general linear group and the symplectic group. By extracting an algebra over a distributive lattice structure from the coordinate ring of the nullcone, we describe a toric degeneration and standard monomial theory of the nullcone in terms of

Liu Weihua, Wu Junde

In this paper, we present a new necessary and sufficient condition for which the supremum exists with respect to the logic order. Moreover, we give out a new and much simpler representation of the supremum with respect to the order, our results have nice physical meanings.

V. W. Marek, J. B. Remmel

We describe a variant of resolution rule of proof and show that it is complete for stable semantics of logic programs. We show applications of this result.

Sergio Cordero, Gaston Garcia-Calderon

We show that an appropriate choice of the potential parameters in one-dimensional quantum systems allows for unity transmission of the tunneling particle at all incident tunneling energies, except at controllable exceedingly small incident energies. The corresponding dwell time and the transmission amplitude are indistinguishable from those of a free particl

I H Hutchinson

It is argued that the form commonly adopted for heuristic representation of tokamak momentum diffusion has major shortcomings, and that a non-diffusive momentum-flux term independent of velocity is more appropriate.

Anna Manka-Krason, Krzysztof Kulakowski

In random networks decorated with Ising spins, an increase of the density of frustrations reduces the transition temperature of the spin-glass ordering. This result is in contradiction to the Bethe theory. Here we investigate if this effect depends on the small-world property of the network. The results on the specific heat and the spin susceptibility indica

Nicusor Costea, Cezar Lupu

Using the KKM technique, we establish some existence results for variational-hemivariational inequalities involving monotone set valued mappings on bounded, closed and convex subsets in reflexive Banach spaces. We also derive several sufficient conditions for the existence of solutions in the case of unbounded subsets.

Guy Louarn, Stéphane Cuenot

Nowadays, silicon micro-cantilevers with different geometrical shapes are widely used as micro-electro-mechanical systems and, more recently, as force sensor probes in atomic force microscopy (AFM). During the last ten years, several applications, which include these AFM micrometer-sized cantilevers as mass probes in microbalances or as chemical sensors in c

Razvan Tudor Radulescu

Previous studies have described the concept of peptide strings in qualitative terms and illustrated it by applying its corrolaries in order to elucidate basic questions in oncology and rheumatology. The present investigation is the first to quantify these potential sub- and transcellular phenomena. Accordingly, the propagation of peptide strings is proposed

Ben Moonen, Alexander Polishchuk

We prove that for any monoid scheme M over a field with proper multiplication maps from M x M to M, we have a natural PD-structure on the ideal CH_{>0}(M) of CH(M) with regard to the Pontryagin ring structure. Further we investigate to what extent it is possible to define a Fourier transform on the motive with integral coefficients of the Jacobian of a curve

Donald Salisbury

Leon Rosenfeld published in 1930 the first systematic Hamiltonian approach to Lagrangian models that possess a local gauge symmetry. The application of this formalism to theories with local internal symmetries, such as electromagnetism in interaction with charged matter fields, is valid and complete, and predates by two decades the work by Dirac and Bergmann

E. Fomalont, S. Kopeikin, G. Lanyi, J. Benson

We have used the Very Long Baseline Array (VLBA) at 43, 23 and 15 GHz to measure the solar gravitational deflection of radio waves among four radio sources during an 18-day period in October 2005. Using phase-referenced radio interferometry to fit the measured phase delay to the propagation equation of the parameterized post-Newtonian (PPN) formalism, we hav

T. Dereli, A. Tegmen, T. Hakioglu

Canonical transformation in a three-dimensional phase space endowed with Nambu bracket is discussed in a general framework. Definition of the canonical transformations is constructed as based on canonoid transformations. It is shown that generating functions, transformed Hamilton functions and the transformation itself for given generating functions can be d

Jan L. Cieslinski

We present algebraic construction of Darboux matrices for 1+1-dimensional integrable systems of nonlinear partial differential equations with a special stress on the nonisospectral case. We discuss different approaches to the Darboux-Backlund transformation, based on different lambda-dependencies of the Darboux matrix: polynomial, sum of partial fractions, o

Dimitris Bertsimas, Dan A. Iancu, Pablo A. Parrilo

In this paper, we show the optimality of a certain class of disturbance-affine control policies in the context of one-dimensional, constrained, multi-stage robust optimization. Our results cover the finite horizon case, with minimax (worst-case) objective, and convex state costs plus linear control costs. We develop a new proof methodology, which explores th

Lijun Zhang, D. J. Singh

The electronic structures of Ba(Fe,Ru)$_2$As$_2$ and Sr(Fe,Ir)$_2$As$_2$ are investigated using density functional calculations. We find that these systems behave as coherent alloys from the electronic structure point of view. In particular, the isoelectronic substitution of Fe by Ru does not provide doping, but rather suppresses the spin density wave charac

Luis F. Alday

Recently a concise expression for the subleading infrared singularity of dimensional-regularized gauge theories has been proposed. For conformal theories, such relation involves a universal eikonal contribution plus a non-eikonal contribution, related to the subleading term in the anomalous dimension of twist two operators with large spin. In this note we ma

Yong Jiang, Jie Sheng

Let $\mathfrak{g}$ be an affine Kac-Moody algebra with symmetric Cartan datum, $\mathfrak{n^{+}}$ be the maximal nilpotent subalgebra of $\mathfrak{g}$. By the Hall algebra approach, we construct integral bases of the $\mathbb{Z}$-form of the enveloping algebra $U(\mathfrak{n^{+}})$. In particular, the representation theory of tame quivers is essentially use

L. Fernández-Jambrina, L. M. González-Romero

In this talk we would like to review recent results on non-singular cosmological models. It has been recently shown that among stiff perfect fluid inhomogeneous spacetimes the absence of singularities is more common than it was expected in the literature. We would like to generalize these results and apply them to other matter sources.

Charles Francis

A class of coordinate systems is found for Friedmann Cosmologies with local gravity such that it is possible to formulate quantum theory over astronomical and cosmological distances. When light from distance objects is treated as a quantum motion, new predictions are found for cosmological redshift and lensing. Good agreement is found between predictions and

M. Bobrowski, A. Lenz, J. Riedl, J. Rohrwild

We reconsider the leading HQE contributions to the absorptive part of the mixing amplitude of neutral $D$ mesons by taking also $α_s$ corrections and subleading $1/m_c$ corrections into account. We show that these contributions to $Γ_{12}$ do not vanish in the exact SU(3)$_F$ limit and they also can have a large phase. Moreover, we give an example of a new p