October 2008 arXiv papers — page 44
Showing 4,301–4,400 of 5,765 papers
M. T. M. van Kessel
We will investigate two models which exhibit SSB in the canonical approach: the N=1 and N=2 linear sigma model. In both models the Green's functions and the effective potential will be computed in the path-integral approach. We will demonstrate how we get different results than in the canonical approach.
Yves Guiraud, Philippe Malbos
We study convergent (terminating and confluent) presentations of n-categories. Using the notion of polygraph (or computad), we introduce the homotopical property of finite derivation type for n-categories, generalizing the one introduced by Squier for word rewriting systems. We characterize this property by using the notion of critical branching. In particul
Sylvain Joubaud, Baptiste Percier, Artem Petrosyan, Sergio Ciliberto
The orientation fluctuations of the director of a liquid crystal(LC) are measured after a quench near the Fréedericksz transition, which is a second order transition driven by an electric field. We report experimental evidence that, because of the critical slowing down, the LC presents, after the quench, several properties of an aging system, such as power l
On the resolution of cosmic coincidence problem and phantom crossing with triple interacting fluids
gr-qcMubasher Jamil, Farook Rahaman
We here investigate a cosmological model in which three fluids interact with each other involving certain coupling parameters and energy exchange rates. The motivation of the problem stems from the puzzling `triple coincidence problem' which naively asks why the cosmic energy densities of matter, radiation and dark energy are almost of the same order of
Shuai Dong, Rong Yu, Seiji Yunoki, Gonzalo Alvarez
The modulation of charge density and spin order in (LaMnO$_3$)$_{2n}$/(SrMnO$_3$)$_n$ ($n$=1-4) superlattices is studied via Monte Carlo simulations of the double-exchange model. G-type antiferromagnetic barriers in the SrMnO$_{3}$ regions with low charge density are found to separate ferromagnetic LaMnO$_{3}$ layers with high charge density. The recently ex
Sinisa Vrecica, Rade Zivaljevic
The cyclohedron (Bott-Taubes polytope) arises both as the polyhedral realization of the poset of all cyclic bracketings of a circular word and as an essential part of the Fulton-MacPherson compactification of the configuration space of n distinct, labelled points on the circle S^1. The "polygonal pegs problem" asks whether every simple, closed curve
Mario G. Abadi, Julio F. Navarro, Matthias Steinmetz
Halo stars with unusually high radial velocity ("hypervelocity" stars, or HVS) are thought to be stars unbound to the Milky Way that originate from the gravitational interaction of stellar systems with the supermassive black hole at the Galactic center. We examine the latest HVS compilation and find peculiarities that are unexpected in this black hol
Hodge polynomials and birational types of moduli spaces of coherent systems on elliptic curves
math.AGH. Lange, P. E. Newstead
In this paper we consider moduli spaces of coherent systems on an elliptic curve. We compute their Hodge polynomials and determine their birational types in some cases. Moreover we prove that certain moduli spaces of coherent systems are isomorphic. This last result uses the Fourier-Mukai transform of coherent systems introduced by Hernández Ruiperez and Tej
Ricardo Mamede
The total number of noncrossing partitions of type $Ψ$ is the $n$th Catalan number $\frac{1}{n+1}\binom{2n}{n}$ when $Ψ=A_{n-1}$, and the binomial $\binom{2n}{n}$ when $Ψ=B_n$, and these numbers coincide with the correspondent number of nonnesting partitions. For type A, there are several bijective proofs of this equality, being the intuitive map that locall
Amita Raval
The H1 and ZEUS collaborations at HERA have searched for signatures of physics beyond the Standard Model using high Q^2 neutral current deep inelastic electron-proton and positron-proton scattering events. No significant deviations from Standard Model predictions were observed. Various eeqq contact interaction models have been considered. Limits on the compo
Marius Buliga
We propose a generalization of hamiltonian mechanics, as a hamiltonian inclusion with convex dissipation function. We obtain a dynamical version of the approach of Mielke to quasistatic rate-independent processes. Then we show that a class of models of dynamical brittle damage can be formulated in this setting.
Aristomenis Donos, Jerome P. Gauntlett, James Sparks
We analyse a recently constructed class of local solutions of type IIB supergravity that consist of a warped product of AdS_3 with a seven-dimensional internal space. In one duality frame the only other non-vanishing fields are the NS three-form and the dilaton. We analyse in detail how these local solutions can be extended to globally well-defined solutions
Rapidly detecting disorder in rhythmic biological signals: A spectral entropy measure to identify cardiac arrhythmias
q-bio.QMPhillip P. A. Staniczenko, Chiu Fan Lee, Nick S. Jones
We consider the use of a running measure of power spectrum disorder to distinguish between the normal sinus rhythm of the heart and two forms of cardiac arrhythmia: atrial fibrillation and atrial flutter. This spectral entropy measure is motivated by characteristic differences in the spectra of beat timings during the three rhythms. We plot patient data deri
J. Przerwa, P. Moskal, A. Budzanowski, E. Czerwinski
A comparison of the close-to-threshold total cross section for the eta prime production in pp --> pp eta prime and pn --> pn eta prime reactions constitutes a tool to investigate the eta prime meson structure and the reaction mechanism in the channels of isospin I=0 and I=1 and may provide insight into the flavour-singlet (perhaps also into gluonium) content
Zurab Berezhiani, Angela Lepidi
Mirror world, a parallel hidden sector with microphysics identical to ordinary particle physics, can have several interesting phenomenological and astrophysical implications and mirror matter can be a natural candidate for dark matter in the universe. If the ordinary and the mirror photons have a kinetic mixing due to the Lagrangian term $(ε/2) F_{μν} F'
NMR relaxation rate and dynamical structure factors in nematic and multipolar liquids of frustrated spin chains under magnetic fields
cond-mat.str-elMasahiro Sato, Tsutomu Momoi, Akira Furusaki
Recently, it has been shown that spin nematic (quadrupolar) or higher multipolar correlation functions exhibit a quasi long-range order in the wide region of the field-induced Tomonaga-Luttinger-liquid (TLL) phase in spin-1/2 zigzag chains. In this paper, we point out that the temperature dependence of the NMR relaxation rate 1/T_1 in these multipolar TLLs i
Henning Krause, Jan Stovicek
For the module category of a hereditary ring, the Ext-orthogonal pairs of subcategories are studied. For each Ext-orthogonal pair that is generated by a single module, a 5-term exact sequence is constructed. The pairs of finite type are characterized and two consequences for the class of hereditary rings are established: homological epimorphisms and universa
Rabia Tahira, Manzoor Ikram, Hyunchul Nha, M. Suhail Zubairy
We study an experimental scheme to generate Gaussian two-mode entangled states via beam splitter. Specifically, we consider a nonclassical Gaussian state (squeezed state) and a thermal state as two input modes, and evaluate the degree of entanglement at the output. Experimental conditions to generate entangled outputs are completely identified and the critic
Semi-empirical formulation of multiple scattering for Gaussian beam model of heavy charged particles stopping in tissue-like matter
physics.med-phNobuyuki Kanematsu
Dose calculation for radiotherapy with protons and heavier ions deals with a large volume of path integrals involving a scattering power of body tissue. This work provides a simple model for such demanding applications. There is an approximate linearity between RMS end-point displacement and range of incident particles in water, empirically found in measurem
Determination of the Strong Coupling \boldmath{\as} from hadronic Event Shapes and NNLO QCD predictions using JADE Data
hep-exS. Bethke, S. Kluth, C. Pahl, J. Schieck
Event Shape Data from $e^+e^-$ annihilation into hadrons collected by the JADE experiment at centre-of-mass energies between 14 GeV and 44 GeV are used to determine the strong coupling $α_S$. QCD predictions complete to next-to-next-to-leading order (NNLO), alternatively combined with resummed next-to-leading-log-approximation (NNLO+NLLA) calculations, are u
Krzysztof R. Apt, Arantza Estévez-Fernández
It is well-known that for several natural decision problems no budget balanced Groves mechanisms exist. This has motivated recent research on designing variants of feasible Groves mechanisms (termed as `redistribution of VCG (Vickrey-Clarke-Groves) payments') that generate reduced deficit. With this in mind, we study sequential mechanisms and consider op
Yoram Gat
Given an IID sample from a positive distribution, we provide a method for constructing rigorous finite sample lower confidence bounds for the expectation of the distribution. The method is based on constructing rigorous confidence regions for the cdf of the distribution. We provide some analysis of the asymptotical behavior of the rigorous LCBs. We apply the
Mixed spin-1/2 and spin-1 Ising model with uniaxial and biaxial single-ion anisotropy on Bethe lattice
cond-mat.stat-mechCesur Ekiz, Jozef Strecka, Michal Jascur
The mixed spin-1/2 and spin-1 Ising model on the Bethe lattice with both uniaxial as well as biaxial single-ion anisotropy terms is exactly solved by combining star-triangle and triangle-star mapping transformations with exact recursion relations. Magnetic properties (magnetization, phase diagrams and compensation phenomenon) are investigated in detail. The
Pseudomodes as an effective description of memory: Non-Markovian dynamics of two-state systems in structured reservoirs
quant-phL. Mazzola, S. Maniscalco, J. Piilo, K. -A. Suominen
We investigate the non-Markovian dynamics of two-state systems in structured reservoirs. We establish a connection between two theoretical quantum approaches, the pseudomodes [B. M. Garraway, Phys. Rev. A 55, 2290 (1997)] and the recently developed non-Markovian quantum jump method [J. Piilo et al., Phys. Rev. Lett. 100, 180402 (2008)]. This connection provi
Dielectric anomalies induced by different mechanisms in Pb(Fe1/2Nb1/2)1-xTixO3 single crystals
cond-mat.mtrl-sciKui Liu, Xinyi Zhang, Shiqiang Wei, H. Oyanagi
We investigated the dielectric properties of Pb(Fe1/2Nb1/2)1-xTixO3 single crystals below room temperature. Two dielectric anomalies were detected in sample A while only one was detected in sample B in the temperature range 90~300 K. A Debye-like relaxation with strong frequency dispersion was detected in both samples. The pre-edge XAFS suggests that this di
Yoshiharu Kawamura
We propose a new grand unification scenario for ensuring proton stability and triplet-doublet Higgs mass splitting with the help of topological symmetry and dynamics.
Giant and negative dielectric tunability induced by interfacial polarization in Pb(Fe1/2Nb1/2)1-xTixO3 single crystals
cond-mat.stat-mechKui Liu, Xinyi Zhang, Jingzhong Xiao
The giant and negative dielectric tunability of Pb(Fe1/2Nb1/2)1-xTixO3 single crystals is reported. A low field of 120 V/cm can induce a great reduction of the capacitance, and the tunability is larger than 80% in low frequency range (<1 MHz) at room temperature. This giant tunability is ascribed to the interfacial polarization at the interface of electrode/
Christopher Manon
We classify exactly when the toric algebras $\C[S_{\tree}(\br)]$ are Gorenstein. These algebras arise as toric deformations of algebras of invariants of the Cox-Nagata ring of the blow-up of $n-1$ points on $\mathbb{P}^{n-3}$, or equivalently algebras of the ring of global sections for the Plücker embedding of weight varieties of the Grassmanian $Gr_2(\C^n)$
Benjamin Howard, Christopher Manon, John Millson
Speyer and Sturmfels [SpSt] associated Gr\"obner toric degenerations $\mathrm{Gr}_2(\C^n)^{\tree}$ of $\mathrm{Gr}_2(\C^n)$ to each trivalent tree $\tree$ with $n$ leaves. These degenerations induce toric degenerations $M_{\br}^{\tree}$ of $M_{\br}$, the space of $n$ ordered, weighted (by $\br$) points on the projective line. Our goal in this paper is to giv
A Hartree-Fock approach to La2CuO4 properties: hints for matching the Mott and Slater pictures
cond-mat.str-elAlejandro Cabo-Bizet, Alejandro Cabo-Montes de Oca
This is extended version of a previously submitted paper, in which special solutions of the Hartree-Fock (HF) problem for Coulomb interacting electrons, being described by a simple model of the Cu-O planes in La2CuO4, are presented. One of the mean field states obtained, is able to predict some of the basic properties of this material, such as its insulator
F. Huang, K. Addas, A. Ward, N. T. Flynn
We report on the construction of colloidal stars: 1 micrometer polystyrene beads grafted with a dense brush of 1 micrometer long and 10 nm wide semi-flexible filamentous viruses. The pair interaction potentials of colloidal stars are measured using an experimental implementation of umbrella sampling, a technique originally developed in computer simulations i
Takeshi Ikeda, Leonardo C. Mihalcea, Hiroshi Naruse
For each infinite series of the classical Lie groups of type B,C or D, we introduce a family of polynomials parametrized by the elements of the corresponding Weyl group of infinite rank. These polynomials represent the Schubert classes in the equivariant cohomology of the appropriate flag variety. They satisfy a stability property, and are a natural extensio
Spontaneous symmetry breaking approach to La2CuO4 properties: hints for matching the Mott and Slater pictures
cond-mat.str-elAlejandro Cabo-Bizet, Alejandro Cabo-Montes-de-Oca
Special solutions of the Hartree-Fock (HF) problem for Coulomb interacting electrons, being described by a simple model of the Cu-O planes in La2CuO4, are presented. One of the mean field states obtained, is able to predict some of the basic properties of this material, such as its insulator character and the antiferromagnetic order. The natural appearance o
Dave Benson, Srikanth B. Iyengar, Henning Krause
We classify localising subcategories of the stable module category of a finite group that are closed under tensor product with simple (or, equivalently all) modules. One application is a proof of the telescope conjecture in this context. Others include new proofs of the tensor product theorem and of the classification of thick subcategories of the finitely g
Yaroslav Tserkovnyak, E. M. Hankiewicz, Giovanni Vignale
We discuss the dissipative diffusion-type term of the form $\mathbf{m}\times\nabla^2\partial_t\mathbf{m}$ in the phenomenological Landau-Lifshitz equation of ferromagnetic precession, which describes enhanced Gilbert damping of finite-momentum spin waves. This term arises physically from itinerant-electron spin flows through a perturbed ferromagnetic configu
Thomas Geisser, Lars Hesselholt
We prove that the relative K-groups associated with a nilpotent extension of Z/p^N Z-algebras and the bi-relative K-groups associated with a Milnor square of Z/p^N Z-algebras are p-primary torsion groups of bounded exponent. We also show that, in general, the cyclotomic trace map extends from Quillen K-theory to Bass completed non-connective algebraic K-theo
Maxime Boissonneault, J. M. Gambetta, Alexandre Blais
Superconducting electrical circuits can be used to study the physics of cavity quantum electrodynamics (QED) in new regimes, therefore realizing circuit QED. For quantum information processing and quantum optics, an interesting regime of circuit QED is the dispersive regime, where the detuning between the qubit transition frequency and the resonator frequenc
Approximation theorems for Banach-valued almost periodic and semi-almost periodic holomorphic functions
math.CVA. Brudnyi, D. Kinzebulatov
The paper studies semi-almost periodic holomorphic functions on a polydisk which have, in a sense, the weakest possible discontinuities on the boundary torus. The basic result used in the proofs is an extension of the classical Bohr approximation theorem for almost periodic holomorphic functions on a strip to the case of Banach-valued almost periodic holomor
Magdalena Constantin, Clare C. Yu, John M. Martinis
We study the charge noise $S_Q$ in Josephson qubits produced by fluctuating two level systems (TLS) with electric dipole moments in the substrate. The TLS are driven by an alternating electric field of angular frequency $Ω$ and electric field intensity $I$. It is not widely appreciated that TLS in small qubits can easily be strongly saturated if $I\gg I_c$,
O. Ivy Wong, Rachel Webster, Virginia Kilborn, Meryl Waugh
We present the Northern HIPASS Optical/InfraRed CATalogue (NOIRCAT), an optical/near-infrared counterpart to the Northern HIPASS catalogue (NHICAT). Of the 1002 sources in NHICAT, 655 (66%) have optical counterparts with matching optical velocities. A further 85 (8%) sources have optical counterparts with matching velocities from previous radio emission-line
Bernardo Spagnolo, Davide Valenti
We shortly review the statistical properties of the escape times, or hitting times, for stock price returns by using different models which describe the stock market evolution. We compare the probability function (PF) of these escape times with that obtained from real market data. Afterwards we analyze in detail the effect both of noise and different initial
L. Mathey, A. Vishwanath, E. Altman
We derive relations between standard order parameter correlations and the noise correlations in time of flight images, which are valid for systems with long range order as well as low dimensional systems with algebraic decay of correlations. Both Bosonic and Fermionic systems are considered. For one dimensional Fermi systems we show that the noise correlatio
Anoosheh Niavarani, Nikolai V. Priezjev
The flow of viscous incompressible fluid over a periodically corrugated surface is investigated numerically by solving the Navier-Stokes equation with the local slip and no-slip boundary conditions. We consider the effective slip length which is defined with respect to the level of the mean height of the surface roughness. With increasing corrugation amplitu
Enrique Soto, Oscar R. Enríquez, Roberto Zenit, Octavio Manero
The climbing effect of a viscoelastic fluid when stirred by a spinning rod is well documented and known as Weissenberg effect(Wei et al, 2006). This phenomenon is related to the elasticity of the fluid. We have observed that this effect can appear when the fluid is stirred without a rod. In this work, a comparison of the flow around a spinning disk for a New
Enrique Soto, Andrew Belmonte
We study the instabilities occurring during the burst of an air balloon in a liquid. These instabilities are typical for the deformation of an interface between two fluids of different densities, similar to fingering in Rayleigh-Taylor instability (see e.g. Sharp, 1984). In the Video a series of bursts are shown for air balloons in different liquids. When th
Enkelejd Hashorva
Let (S_1,S_2)=(R \cos(Θ), R \sin (Θ)) be a bivariate random vector with associated random radius R which has distribution function $F$ being further independent of the random angle Θ. In this paper we investigate the asymptotic behaviour of the conditional survivor probability Ψ_{ρ,u}(y):=\pk{ρS_1+ \sqrt{1- ρ^2} S_2> y \lvert S_1> u}, ρ\in (-1,1),\in R when
M. Jeng, S. -L. -Y. Xu, E. Hawkins, J. M. Schwarz
A number of papers over the past eight years have claimed to solve the fractional Schrödinger equation for systems ranging from the one-dimensional infinite square well to the Coulomb potential to one-dimensional scattering with a rectangular barrier. However, some of the claimed solutions ignore the fact that the fractional diffusion operator is inherently
J. C. Morales, I. Ribas, C. Jordi, G. Torres
Spectroscopic and eclipsing binary systems offer the best means for determining accurate physical properties of stars, including their masses and radii. The data available for low-mass stars have yielded firm evidence that stellar structure models predict smaller radii and higher effective temperatures than observed, but the number of systems with detailed a
Performance Analysis of 60nm gate length III-V InGaAs HEMTs: Simulations vs. experiments
cond-mat.mes-hallNeophytos Neophytou, Titash Rakshit, Mark S. Lundstrom
An analysis of recent experimental data for high-performance In0.7Ga0.3As high electron mobility transistors (HEMTs) is presented. Using a fully quantum mechanical, ballistic model, we simulate In0.7Ga0.3As HEMTs with gate lengths of LG = 60nm, 85, and 135 nm and compare the result to the measured I-V characteristics including draininduced barrier lowering,
Andrew Kunz, Eric C. Breitbach, Andrew J. Smith
In a thin magnetic nanostripe, an anti-vortex nucleates inside a moving domain wall when driven by an in-plane magnetic field greater than the so-called Walker field. The nucleated anti-vortex must cross the width of the nanostripe before the domain wall can propagate again, leading to low average domain wall speeds. A large out-of-plane magnetic field, appl
Finite size fluctuations and stochastic resonance in globally coupled bistable systems
cond-mat.stat-mechDavid Cubero
The dynamics of a system formed by a finite number $N$ of globally coupled bistable oscillators and driven by external forces is studied focusing on a global variable defined as the arithmetic mean of each oscillator variable. Several models based on truncation schemes of a hierarchy of stochastic equations for a set of fluctuating cumulant variables are pre
A. Marshakov
I discuss particular solutions of the integrable systems, starting from well-known dispersionless KdV and Toda hierarchies, which define in most straightforward way the generating functions for the Gromov-Witten classes in terms of the rational complex curve. On the ``mirror'' side these generating functions can be identified with the simplest prepot
Roberto P. Muñoz, Nelson D. Padilla, Luis F. Barrientos
We study the reliability of the statistical background subtraction method for computing the Ks-band luminosity function of cluster galaxies at z~1 using mock Red-sequence Cluster Survey cluster catalogues constructed from GALFORM semi-analytic galaxies. The underlying cluster luminosity function in the mocks are compatible with recent estimates at z~1 by sev
Richard Whisker
In this thesis we investigate black holes in the Randall-Sundrum braneworld scenario. We begin with an overview of extra-dimensional physics, from the original proposal of Kaluza and Klein up to the modern braneworld picture of extra dimensions. A detailed description of braneworld gravity is given, with particular emphasis on its compatibility with experime
Artur Avila
We show that smooth maps are $C^1$-dense among $C^1$ volume preserving maps.
Jacob Greenstein
Let $\mathfrak g$ be a complex simple Lie algebra and let $Ψ$ be an extremal set of positive roots. One associates with $Ψ$ an infinite dimensional Koszul algebra $\bold S_Ψ^{\lie g}$ which is a graded subalgebra of the locally finite part of $((\bold V)^{op}\tensor S(\lie g))^{\lie g}$, where $\bold V$ is the direct sum of all simple finite dimensional $\li
The method of the weakly conjugate operator: Extensions and applications to operators on graphs and groups
math-phM. Mantoiu, S. Richard, R. Tiedra de Aldecoa
In this review we present some recent extensions of the method of the weakly conjugate operator. We illustrate these developments through examples of operators on graphs and groups.
Roberto Frigerio, Alessandro Sisto
Let X be a geodesic metric space. Gromov proved that there exists k>0 such that if every sufficiently large triangle T satisfies the Rips condition with constant k times pr(T), where pr(T) is the perimeter T, then X is hyperbolic. We give an elementary proof of this fact, also giving an estimate for k. We also show that if all the triangles T in X satisfy th
Benjamin F. Collins, Re'em Sari
We examine the evolution of an almost circular Keplerian orbit interacting with unbound perturbers. We calculate the change in eccentricity and angular momentum that results from a single encounter, assuming the timescale for the interaction is shorter than the orbital period. The orbital perturbations are incorporated into a Boltzmann equation that allows f
G. Sala, J. Greiner, M. Ajello, N. Primak
On 28 February 2007 a new outburst of the previously known transient source XTE J1856+053 was detected with RXTE/ASM. We present here the results of an XMM-Newton (0.5-10.0 keV) Target of Opportunity observation performed on 14 March 2007, aimed at constraining the mass of the compact object in this X-ray binary and determining its main properties. The EPIC-
Long-Term Evolution of and X-ray Emission from a Recoiling Supermassive Black Hole in a Disk Galaxy
astro-phYutaka Fujita
Recent numerical relativity simulations have shown that the emission of gravitational waves at the merger of two black holes gives a recoil kick to the final black hole. We follow the orbits of a recoiling supermassive black hole (SMBH) in a fixed background potential of a disk galaxy including the effect of dynamical friction. If the recoil velocity of the
Michael A. Nowak
We present highlights from a series of four simultaneous Suzaku/RXTE observations of the black hole candidate Cyg X-1. We briefly summarize several key results from our decade long RXTE monitoring campaign. We then comment on challenges of analyzing the Suzaku data, i.e., improving the aspect correction beyond that of the existing tools, and quantitatively a
Stanislaw Mrowczynski
Chromodynamic fluctuations in the collisionless quark-gluon plasma are found as a solution of the initial value linearized problem. The stable and unstable plasmas are discussed.
B. X. Santiago
More than 50 years have elapsed since the first studies of star clusters in the Magellanic Clouds. The wealth of data accumulated since then has not only revealed a large cluster system, but also a diversified one, filling loci in the age, mass and chemical abundance parameter space which are complementary to Galactic clusters. Catalogs and photometric sampl
Ijaz Haider Naqvi, Tanguy Pérennou
Existing transport protocols, be it TCP, SCTP or DCCP, do not provide an efficient congestion control mechanism for heterogeneous wired-cum-wireless networks. Solutions involving implicit loss discrimination schemes have been proposed but were never implemented. Appropriate mechanisms can dramatically improve bandwidth usage over the Internet, especially for
E. F. Keane, M. Kramer
In light of the recently discovered neutron star populations we discuss the various estimates for the birthrates of these populations. We revisit the question as to whether the Galactic supernova rate can account for all of the known groups of isolated neutron stars. After reviewing the rates and population estimates we find that, if the estimates are in fac
Systemic Proper Motions of Milky Way Satellites from Stellar Redshifts: the Carina, Fornax, Sculptor and Sextans Dwarf Spheroidals
astro-phMatthew G. Walker, Mario Mateo, Edward W. Olszewski
The transverse motions of nearby dwarf spheroidal (dSph) galaxies contribute line-of-sight components that increase with angular distance from the dSph centers, inducing detectable gradients in stellar redshift. In the absence of an intrinsic velocity gradient (e.g., due to rotation or streaming), an observed gradient in the heliocentric rest frame (HRF) rel
O. Kochukhov
High time resolution spectroscopy of roAp stars at large telescopes has led to a major breakthrough in our understanding of magnetoacoustic pulsations in these interesting objects. New observations have allowed to uncover a number of intricate relations between stellar oscillations, magnetic field, and chemical inhomogeneities. It is now understood that unus
Ijaz Haider Naqvi, Ali Khaleghi, Ghaïs El Zein
UWB communication is a recent research area for indoor propagation channels. Time Reversal (TR) communication in UWB has shown promising results for improving the system performance. In multiuser environment, the system performance is significantly degraded due to the interference among different users. TR reduces the interference caused by multiusers due to
B. X. Santiago
Luminous elliptical galaxies generally display a rich star cluster system, whose properties provide strong constraints on the physics of galaxy formation and evolution. Star cluster system studies, however, concentrate on galaxies located in nearby or rich galaxy clusters. We acquired deep B and I images of NGC 1600, a luminous elliptical in a galaxy group t
Algebraic Geometry Approach in Theories with Extra Dimensions II. Tensor Length Scale, Compactification and Rescaling
hep-thBogdan G. Dimitrov
In this second part of the paper, dedicated to theories with extra dimensions, a new physical notion about the "tensor length scale" is introduced, based on the gravitational theories with covariant and contravariant metric tensor components. Then the notion of "compactification" in low energy type I string theory is supplemented by the opera
Algebraic Geometry Approach in Theories with Extra Dimensions I. Application of Lobachevsky Geometry
hep-thBogdan G. Dimitrov
This present paper has the purpose to find certain physical appications of Lobachevsky geometry and of the algebraic geometry approach in theories with extra dimensions. It has been shown how the periodic properties of the uniformization functions-solutions of cubic algebraic equations in gravity theory enable the orbifold periodic identification of the poin
Momentum average approximation for models with electron-phonon coupling dependent on the phonon momentum
cond-mat.str-elGlen L. Goodvin, Mona Berciu
We generalize the momentum average (MA) approximation to study the properties of models with momentum-dependent electron-phonon coupling. As in the case of the application of the original MA to the Holstein model, the results are analytical, numerically trivial to evaluate, exact for both zero bandwidth and for zero electron-phonon coupling, and are accurate
Kaustubh Agashe, Shrihari Gopalakrishna, Tao Han, Gui-Yu Huang
We study signals at the Large Hadron Collider (LHC) for the Kaluza-Klein (KK) excitations of electroweak charged gauge bosons in the framework of the Standard Model (SM) fields propagating in the bulk of a warped extra dimension. Such a scenario can solve both the Planck-weak and flavor hierarchy problems of the SM. There are two such charged states in this
X. Rebecca Nie, Christian F. Roos, Daniel F. V. James
We analyze nonlinear coupling between individual vibrational quanta for trapped ions. The nonlinear Coulomb interaction causes a Kerr-type Hamiltonian, for which we derive an analytical expression for the coupling constant. In contrast to a previously published formula [1], our result is in close agreement with experimental data.
F. -J. Jiang, B. C. Tiburzi
Using flavor twisted boundary conditions, we study nucleon matrix elements of the vector current. We twist only the active quarks that couple to the current. Finite volume corrections due to twisted boundary conditions are determined using partially twisted, partially quenched, heavy baryon chiral perturbation theory, which we develop for the graded group SU
A. A. Dubkov, B. Spagnolo, V. V. Uchaikin
After a short excursion from discovery of Brownian motion to the Richardson "law of four thirds" in turbulent diffusion, the article introduces the Lévy flight superdiffusion as a self-similar Lévy process. The condition of self-similarity converts the infinitely divisible characteristic function of the Lévy process into a stable characteristic funct
P Canizares, A Conchillo, E Garcia-Berro, L Gesa
The Data and Diagnostics Subsystem of the LTP hardware and software are at present essentially ready for delivery. In this presentation we intend to describe the scientific and technical aspects of this subsystem, which includes thermal diagnostics, magnetic diagnostics and a Radiation Monitor, as well as the prospects for their integration within the rest o
Joris Vankerschaver, Eva Kanso, Jerrold E. Marsden
We derive the equations of motion for a planar rigid body of circular shape moving in a 2D perfect fluid with point vortices using symplectic reduction by stages. After formulating the theory as a mechanical system on a configuration space which is the product of a space of embeddings and the special Euclidian group in two dimensions, we divide out by the pa
Y. Kim, I. L. Andronov, S. M. Cha, L. L. Chinarova J. -N. Yoon
We study the variability of the nova-like cataclysmic variable TT Ari, on time-scales of between minutes and months. The observations in the filter R were obtained at the 40-cm telescope of the Chungbuk National University (Korea). TT Ari was in the "negative superhump" state after its return from the "positive superhump" state, which lasted
Katalin Gyarmati, Mate Matolcsi, Imre Z. Ruzsa
The aim of this paper is to prove a general version of Plünnecke's inequality. Namely, assume that for finite sets $A$, $B_1, ... B_k$ we have information on the size of the sumsets $A+B_{i_1}+... +B_{i_l}$ for all choices of indices $i_1, ... i_l.$ Then we prove the existence of a non-empty subset $X$ of $A$ such that we have `good control' over the
Bernardo Spagnolo, Alexander A. Dubkov
Editorial of the International Conference on Critical Phenomena and Diffusion in Complex Systems held on 5--7 December, 2006 in Nizhniy Novgorod State University, Russia and was dedicated to the memory and 80th anniversary of Professor Askold N. Malakhov.
Mate Matolcsi, Imre Z. Ruzsa
We extend Freiman's inequality on the cardinality of the sumset of a $d$ dimensional set. We consider different sets related by an inclusion of their convex hull, and one of them added possibly several times.
J. Gillet, T. Bastin, G. S. Agarwal
We formulate an entanglement criterion using Peres-Horodecki positive partial transpose operations combined with the Schrödinger-Robertson uncertainty relation. We show that any pure entangled bipartite and tripartite state can be detected by experimentally measuring mean values and variances of specific observables. Those observables must satisfy a specific
A modified characteristic finite element method for a fully nonlinear formulation of the semigeostrophic flow equations
math.NAXiaobing Feng, Michael Neilan
This paper develops a fully discrete modified characteristic finite element method for a coupled system consisting of the fully nonlinear Monge-Ampére equation and a transport equation. The system is the Eulerian formulation in the dual space for the B. J. Hoskins' semigeostrophic flow equations, which are widely used in meteorology to model slowly varyi
F. K. Schinzel, G. B. Taylor, C. J. Stockdale, J. Granot
SN 2001em is a peculiar supernova, originally classified as Type Ib/c. About two years after the SN it was detected in the radio, showing a rising radio flux with an optically thin spectral slope, and it also displayed a large X-ray luminosity (~10^{41} erg/s). Thus it was suspected to harbor a decelerating (by then, mildly) relativistic jet pointing away fr
O. V. Dolgov, I. I. Mazin, D. Parker, A. A. Golubov
The newly discovered iron pnictide superconductors apparently present an unusual case of interband-channel pairing superconductivity. Here we show that, in the limit where the pairing occurs within the interband channel, several surprising effects occur quite naturally and generally: different density-of-states on the two bands lead to several unusual proper
Xiaobing Feng, Haijun Wu
This paper develops and analyzes some interior penalty discontinuous Galerkin methods using piecewise linear polynomials for the Helmholtz equation with the first order absorbing boundary condition in the two and three dimensions. It is proved that the proposed discontinuous Galerkin methods are stable (hence well-posed) without any mesh constraint. For each
Nicolae Mihalache
In rational dynamics, we prove the existence of a polynomial that satisfies the Topological Collet-Eckmann condition, but which has a recurrent critical orbit that is not Collet-Eckmann. This shows that the converse of the main theorem in [11] does not hold. In interval dynamics, we show that the Collet-Eckmann property for recurrent critical orbits is not a
Daniel P. Stark, Mark Swinbank, Richard S. Ellis, Simon Dye
Recent studies of galaxies ~2-3 Gyr after the Big Bang have revealed large, turbulent rotating systems. The existence of well-ordered rotation in galaxies during this peak epoch of cosmic star formation may suggest that gas accretion through cold streams is likely to be the dominant mode by which most star-forming galaxies at high redshift since major merger
John Bulava, Robert Edwards, Colin Morningstar
The effectiveness of various dilution schemes in the evaluation of baryonic two-point functions is compared. The error of a representative set of observables as a function of the number of Dirac matrix inversions is used as a basis for comparison. To achieve an equivalent reduction in error, we demonstrate that an increase in the number of dilution projector
Rebeca Gonzalez Suarez
A prospective analysis for the search of the Standard Model (SM) Higgs boson with the CMS detector is presented in the context of the early LHC data. The aim is to establish an analysis strategy for inclusive production of the Higgs boson decaying in WW* pairs in the context of the early LHC data. Higgs mass region between 120-200 GeV, in which this signatur
Ahmad T. Ali, Rafael López
We consider a curve $α=α(s)$ in Minkowski 3-space $E_1^3$ and denote by $\{T,N,B}$ the Frenet frame of $α$. We say that $α$ is a slant helix if there exists a fixed direction $U$ of $E_1^3$ such that the function $<N(s),U>$ is constant. In this work we give characterizations of slant helices in terms of the curvature and torsion of $α$.
Arezky H. Rodríguez, Lilia Meza-Montes, Carlos Trallero-Giner, Sergio E. Ulloa
Theoretical results for a single electron in multi-level system given by a lens-shape self-assembled quantum dot in the presence of an intense harmonic electric field are presented. A non-perturbative Floquet approach is used to study the dynamical localization of the particle when going beyond the two-level approach by introducing the full spectral level st
Ahmad T. Ali, Rafael López
We consider a unit speed timelike curve $α$ in Minkowski 4-space $E_1^4$ and denote the Frenet frame of $α$ by $\{T,N,B_1,B_2\}$. We say that $α$ is a generalized helix if one of the unit vector fields of the Frenet frame has constant scalar product with a fixed direction $U$ of $E_1^4$. In this work we study those helices where the function $<B_2,U>$ is con
Alan Kostelecky, Jay Tasson
Deviations from relativity are tightly constrained by numerous experiments. A class of unmeasured and potentially large violations is presented that can be tested in the laboratory only via weak gravity couplings. Specialized highly sensitive experiments could achieve measurements of the corresponding effects. A single constraint of 1 x 10^{-11} GeV is extra
Analytical obtention of eigen-energies for lens-shaped quantum dot with finite barriers
cond-mat.mes-hallArezky H. Rodríguez, Hanz Y. Ramírez
The bound states of a particle in a lens-shaped quantum dot with finite confinement potential are obtained in the envelope function approximation. The quantum dot has circular base with radius $a$ and maximum cap height $b$, and the effective mass of the particle is considered different inside and outside the dot. A 2D Fourier expansion is used in a semi-sph
S. Giagu
The ATLAS and CMS detectors can be used to search for heavy long-lived particles which might signal physics beyond the Standard Model. Such new states can be distinguished from Standard Model particles by exploiting their unique signatures, ranging from multi-leptons and/or jets pro- duction anywhere within the detector volume, to minimum ionizing particles
D. Dornic, G. Lelaizant
Gamma-ray bursts (GRB) are powerful and highly variable sources of gamma rays that indicate the existence of cosmic particle accelerators. Under the assumption of hadronic acceleration in the jet, the expected neutrino energy spectrum is derived according to the intrinsic fireball model parameters and to the observed electromagnetic data of GRBs measured wit
Optical transition in self-assembled InAs/GaAs quantum lens under high hydrostatic pressure
cond-mat.mes-hallArezky H. Rodríguez, C. Trallero-Giner, C. A. Duque, G. J. Vázquez
We present a simulation to characterize the dependence on hydrostatic pressure for the photoluminescence spectra in self-assembled quantum dots with lens shape geometry. We have tested the physical effects of the band offset and electron-hole effective masses on the optical emission in dot lens. The model could be implemented to get qualitative information o