October 2011 arXiv papers — page 7
Showing 601–700 of 6,952 papers
X-ray spectral states and metallicity in the ultraluminous X-ray sources NGC 1313 X-1 and X-2
astro-ph.HEFabio Pintore, Luca Zampieri
We present a systematic analysis of the X-ray spectra of NGC 1313 X-1 and NGC 1313 X-2, using three years of XMM-Newton observations. We fitted the continuum with a Comptonization model plus a multicolor blackbody disc, that describes the effects of an accretion disc plus a corona. We checked the consistency of this spectral model on the basis of the variabi
Xiaoxian Tang, Bican Xia
A new concept, decomposition-unstable (DU) variety of a parametric polynomial system, is introduced in this paper and the stabilities of several triangular decomposition methods, such as characteristic set decomposition, relatively simplicial decomposition and regular chain decomposition, for parametric polynomial systems are discussed in detail. The concept
Valeri P. Frolov
We study collision of particles in the vicinity of a horizon of a weakly magnetized non-rotating black hole. In the presence of the magnetic field innermost stable circular orbits (ISCO) of charged particles can be located close to the horizon. We demonstrate that for a collision of two particles, one of which is charged and revolving at ISCO and the other i
Hervé Fournier, Guillaume Malod, Stefan Mengel
We consider the complexity of two questions on polynomials given by arithmetic circuits: testing whether a monomial is present and counting the number of monomials. We show that these problems are complete for subclasses of the counting hierarchy which had few or no known natural complete problems. We also study these questions for circuits computing multili
Yaxiang Li, Matti Vuorinen, Xiantao Wang
Suppose that $E$ and $E'$ denote real Banach spaces with dimension at least 2, that $D\subset E$ and $D'\subset E'$ are domains, and that $f: D\to D'$ is a homeomorphism. In this paper, we prove that if there exists some constant $M>1$ (resp. some homeomorphism $ϕ$) such that for all $x\in D$, $f: B(x,d_D(x))\to f(B(x,d_D(x)))$ is $M$-QH (res
Wojciech Mazurczyk, Pawel Kopiczko
In this paper the results of the BitTorrent measurement study are presented. Two sources of BitTorrent data were utilized: meta-data files that describe the content of resources shared by BitTorrent users and the logs of one of the currently most popular BitTorrent clients - μTorrent. μTorrent is founded upon a rather newly released UDP-based μTP protocol th
Gregory Gauthier
We investigate the avalanche dynamics of the abelian sandpile model on arbitrarily large balls of the expanded cactus graph (the Cayley graph of the free product $\mathbb{Z}_3 * \mathbb{Z}_2$). We follow the approach of Dhar and Majumdar (1990) to enumerate the number of recurrent configurations. We also propose the filling method of enumerating all the recu
Critical temperature and correlation length of an elastic interaction model for spin-crossover materials
cond-mat.stat-mechTaro Nakada, Takashi Mori, Seiji Miyashita, Masamichi Nishino
It has previously been pointed out that the coexistence of infinite-range and short-range interactions causes a system to have a phase transition of the mean-field universality class, in which the cluster size is finite even at the critical point. In the present paper, we study this property in a model of bistable molecules, whose size changes depending on t
Convergence Rate of Zero Viscosity Limit on Large Amplitude Solution to a Conservation Laws Arising in Chemotaxis
math.APHongyun Peng, Lizhi Ruan, Changjiang Zhu
In this paper, we investigate large amplitude solutions to a system of conservation laws which is transformed, by a change of variable, from the well-known Keller-Segel model describing cell (bacteria) movement toward the concentration gradient of the chemical that is consumed by the cells. For the Cauchy problem and initial-boundary value problem, the globa
Stefan Boettcher, Stefan Falkner
Extensive computations of ground state energies of the Edwards-Anderson spin glass on bond-diluted, hypercubic lattices are conducted in dimensions d=3,..,7. Results are presented for bond-densities exactly at the percolation threshold, p=p_c, and deep within the glassy regime, p>p_c, where finding ground-states becomes a hard combinatorial problem. Finite-s
Hayato Motohashi, Teruaki Suyama
Chern-Simons gravitational theories are extensions of general relativity in which the parity is violated due to the Chern-Simons term. We study linear perturbations on the static and spherically symmetric background spacetime both for nondynamical and dynamical Chern-Simons theories. We do not make an assumption that the background Chern-Simons scalar field
Stephen Pankavich, Petronela Radu
We consider semilinear evolution equations of the form $a(t)\partial_{tt}u + b(t) \partial_t u + Lu = f(x,u)$ and $b(t) \partial_t u + Lu = f(x,u),$ with possibly unbounded $a(t)$ and possibly sign-changing damping coefficient $b(t)$, and determine precise conditions for which linear instability of the steady state solutions implies nonlinear instability. Mo
Duong Quoc Viet, Le Van Dinh, Truong Thi Hong Thanh
Let $(A, \frak m)$ be a noetherian local ring with maximal ideal $\frak{m}$ and infinite residue field $k = A/\frak{m}.$ Let $J$ be an $\frak m$-primary ideal, $I_1,...,I_s$ ideals of $A$, and $M$ a finitely generated $A$-module. In this paper, we interpret mixed multiplicities of $(I_1,..., I_s,J)$ with respect to $M$ as multiplicities of joint reductions o
Yu-Dai Tsai, Hsiang-nan Li, Qiang Zhao
We include the $η_c$ meson into the $η$-$η'$-$G$ mixing formalism constructed in our previous work, where $G$ represents the pseudoscalar gluball. The mixing angles in this tetramixing matrix are constrained by theoretical and experimental implications from relevant hadronic processes. Especially, the angle between $η_c$ and $G$ is found to be about $11^
Chian-Shu Chen, Thomas W. Kephart, Tzu-Chiang Yuan
To include the quark sector, the $A_{5}\equiv I$ (icosahedron) four generation lepton model is extended to a binary icosahedral symmetry $I'$ flavor model. We find the masses of fermions, including the heavy sectors, can be accommodated. At leading order the CKM matrix is the identity and the PMNS matrix, resulting from same set of vacua, corresponds to
Devavrat Shah, Tauhid Zaman
We consider the problem of detecting the source of a rumor which has spread in a network using only observations about which set of nodes are infected with the rumor and with no information as to \emph{when} these nodes became infected. In a recent work \citep{ref:rc} this rumor source detection problem was introduced and studied. The authors proposed the gr
Vladimir A. Zyuzin, Gregory A. Fiete
We theoretically study the spatially anisotropic spin-1/2 kagome antiferromagnet with Dzyaloshinskii-Moriya (DM) interaction using a renormalization group analysis in the quasi-one-dimensional limit. We identify the various temperature and energy scales for ordering in the system. For very weak DM interaction, we find a low-temperature spiral phase with the
A. Lykov, S. Muzychka, K. Vaninsky
We introduce a dynamical system which we call the AdaBoost flow. The flow is defined by a system of ODEs with control. We show that three algorithms of the AdaBoost family (i) the AdaBoost algorithm of Schapire and Freund (ii) the arc-gv algorithm of Breiman (iii) the confidence rated prediction of Schapire and Singer can be can be embedded in the AdaBoost f
Greg J. Schwarz, Jan-Uwe Ness, J. P. Osborne, K. L. Page
The Swift GRB satellite is an excellent facility for studying novae. Its rapid response time and sensitive X-ray detector provides an unparalleled opportunity to investigate the previously poorly sampled evolution of novae in the X-ray regime. This paper presents Swift observations of 52 Galactic/Magellanic Cloud novae. We included the XRT (0.3-10 keV) X-ray
Pablo Vázquez Regueiro, Eliseo Pérez Trigo, Pablo Rodríguez Pérez
The Pixel Detector (PXD) of the Belle II experiment at superKEKB accelerator in Japan is based in the DEPFET technology. Two layers of 8+12 modules at a radius of 13 and 22 mm will give a spatial resolution below 10 mm. The radiation level expected in the first layer in ten years of operation is about 10 MRad of total ionizing dose. In order to study the tol
Ryo Takei, Weiyan Chen, Zachary Clawson, Slav Kirov
We consider both discrete and continuous control problems constrained by a fixed budget of some resource, which may be renewed upon entering a preferred subset of the state space. In the discrete case, we consider both deterministic and stochastic shortest path problems with full budget resets in all preferred nodes. In the continuous case, we derive augment
Roman V. Yampolskiy
In this paper we present a Hashed-Path Traveling Salesperson Problem (HPTSP), a new type of problem which has the interesting property of having no polynomial time solutions. Next we show that HPTSP is in the class NP by demonstrating that local information about sub-routes is insufficient to compute the complete value of each route. As a consequence, via La
Dan A. Lee
We prove that the positive mass theorem applies to Lipschitz metrics as long as the singular set is low-dimensional, with no other conditions on the singular set. More precisely, let $g$ be an asymptotically flat Lipschitz metric on a smooth manifold $M^n$, such that $n<8$ or $M$ is spin. As long as $g$ has bounded $C^2$ norm and nonnegative scalar curvature
M. F. Aller, P. A. Hughes, H. D. Aller, A. P. Marscher
We present centimeter-band total flux density and linear polarization light curves illustrating the signature of shocks during radio band outbursts associated in time with gamma-ray flares detected by the Fermi LAT. The general characteristics of the spectral evolution during these events is well-explained by new radiative transfer simulations incorporating
Gábor Tardos
A graph drawn in the plane with straight-line edges is called a geometric graph. If no path of length at most $k$ in a geometric graph $G$ is self-intersecting we call $G$ $k$-locally plane. The main result of this paper is a construction of $k$-locally plane graphs with a super-linear number of edges. For the proof we develop randomized thinning procedures
Yuan Li, David Murrugarra, John O. Adeyeye, Reinhard Laubenbacher
In this paper, we extend the definition of Boolean canalyzing functions to the canalyzing functions over finite field $\mathbb{F}_{q}$, where $q$ is a power of a prime. We obtain the characterization of all the eight classes of such functions as well as their cardinality. When $q=2$, we obtain a combinatorial identity by equating our result to the formula in
Heavy sterile neutrinos, entropy and relativistic energy production, and the relic neutrino background
astro-ph.COGeorge M. Fuller, Chad T. Kishimoto, Alexander Kusenko
We explore the implications of the existence of heavy neutral fermions (i.e., sterile neutrinos) for the thermal history of the early universe. In particular, we consider sterile neutrinos with rest masses in the 100 MeV to 500 MeV range, with couplings to ordinary active neutrinos large enough to guarantee thermal and chemical equilibrium at epochs in the e
Universal Finite Temperature Properties of a Three Dimensional Quantum Antiferromagnet in the Vicinity of a Quantum Critical Point
cond-mat.str-elJ. Oitmaa, Y. Kulik, O. P. Sushkov
We consider a 3-dimensional quantum antiferromagnet which can be driven through a quantum critical point (QCP) by varying a tuning parameter g. Starting from the magnetically ordered phase, the N{é}el temperature will decrease to zero as the QCP is approached. From a generic quantum field theory, together with numerical results from a specific microscopic He
Tzu-Han Chou, Stark C. Draper, Akbar M. Sayeed
We study the fundamental limits to secret key generation from an excited distributed source (EDS). In an EDS a pair of terminals observe dependent sources of randomness excited by a pre-arranged signal. We first determine the secret key capacity for such systems with one-way public messaging. We then characterize a tradeoff between the secret key rate and ex
Mario I. Molina, Andrey E. Miroshnichenko, Yuri S. Kivshar
We introduce a novel concept of surface bound states in the continuum, i.e. surface modes embedded into the linear spectral band of a discrete lattice. We suggest an efficient method for creating such surface modes and the local bounded potential necessary to support such embedded modes. We demonstrate that the embedded modes are structural stable, and the p
X. Li, B. D. Kong, J. M. Zavada, K. W. Kim
The Joule heating effect on graphene electronic properties is investigated by using full-band Monte Carlo electron dynamics and three-dimensional heat transfer simulations self-consistently. A number of technologically important substrate materials are examined: SiO2, SiC, hexagonal BN, and diamond. The results illustrate that the choice of substrate has a m
The Interplanetary Network Supplement to the Fermi GBM Catalog - An AO-2 and AO-3 Guest Investigator Project
astro-ph.HEK. Hurley, M. Briggs, V. Connaughton, C. Meegan
In the first two years of operation of the Fermi GBM, the 9-spacecraft Interplanetary Network (IPN) detected 158 GBM bursts with one or two distant spacecraft, and triangulated them to annuli or error boxes. Combining the IPN and GBM localizations leads to error boxes which are up to 4 orders of magnitude smaller than those of the GBM alone. These localizati
An Algorithm for the Stochastic Simulation of Gene Expression and Heterogeneous Population Dynamics
physics.comp-phDaniel A. Charlebois, Jukka Intosalmi, Dawn Fraser, Mads Kaern
We present an algorithm for the stochastic simulation of gene expression and heterogeneous population dynamics. The algorithm combines an exact method to simulate molecular-level fluctuations in single cells and a constant-number Monte Carlo method to simulate time-dependent statistical characteristics of growing cell populations. To benchmark performance, w
M. J. Roy, R. J. Klassen, J. T. Wood
The distribution of equivalent plastic strain through the thickness of several AISI 1020 steel plates formed under different conditions over a smooth cylindrical mandrel using a single-roller forward flow forming operation was studied by measuring the local micro-indentation hardness of the deformed material. The equivalent plastic strain was higher at the i
Yasuyuki Kato, K. A. Al-Hassanieh, A. E. Feiguin, Eddy Timmermans
We show that a single impurity embedded in a cold atom bosonic Mott insulator leads to a novel polaron that exhibits correlated motion with an effective mass and a linear size that nearly diverge at critical value of the on-site impurity-boson interaction strength. Cold atom technology can tune the polaron's properties and break up the composite particle
Marc Masdeu
Let f be a modular form of weight k>=2 and level N, let K be a quadratic imaginary field, and assume that there is a prime p exactly dividing N. Under certain arithmetic conditions on the level and the field K, one can attach to this data a p-adic L-function L_p(f,K,s), as done by Bertolini-Darmon-Iovita-Spiess. In the case of p being inert in K, this analyt
David Romero Abad, Orlando Pereyra Ravinez
Based on the expectation generated by the discovery of new particles by current colliders, we analyze the decay of the Z' boson in the frame of one of the SU(3)L \otimes U(1)N electroweak extensions of the standard model. The main objective is calculate the decay rate of this exotic boson in the aforementioned model at the tree level. With this purpose w
I. Agudo, S. G. Jorstad, A. P. Marscher, V. M. Larionov
We combine the Fermi-LAT light curve of the BL Lacertae type blazar OJ287 with time-dependent multi-waveband flux and linear polarization observations and submilliarcsecond-scale polarimetric images at lambda=7mm to locate the gamma-ray emission in prominent flares in the jet of the source >14pc from the central engine. We demonstrate a highly significant co
Yvonne Pachmayer
The measurement of heavy-flavour production in pp collisions at the LHC allows to study the production mechanisms and to test perturbative Quantum Chromodynamics (pQCD) in a new energy domain. Further it provides important reference data for investigations of the medium effects in Pb-Pb collisions, where charm and beauty production measurements are regarded
Measurement of the Production Cross Section for Pairs of Isolated Photons in pp collisions at sqrt(s) = 7 TeV
hep-exCMS Collaboration
The integrated and differential cross sections for the production of pairs of isolated photons is measured in proton-proton collisions at a centre-of-mass energy of 7 TeV with the CMS detector at the LHC. A data sample corresponding to an integrated luminosity of 36 inverse picobarns is analysed. A next-to-leading-order perturbative QCD calculation is compar
Dylan R. Harp, Velimir V. Vesselinov
Decision making under severe lack of information is a ubiquitous situation in nearly every applied field of engineering, policy, and science. A severe lack of information precludes our ability to determine a frequency of occurrence of events or conditions that impact the decision; therefore, decision uncertainties due to a severe lack of information cannot b
Study of the impact of the post-MS evolution of the host star on the orbits of close-in planets. I. Sample definition and physical properties
astro-ph.EPM. I. Jones, J. S. Jenkins, P. Rojo, C. H. F. Melo
Context: To date, more than 30 planets have been discovered around giant stars, but only one of them has been found to be orbiting within 0.6 AU from the host star, in direct contrast to what is observed for FGK dwarfs. This result suggests that evolved stars destroy/engulf close-in planets during the red giant phase. Aims: We are conducting a radial velocit
On the confinement of a quantum particle to a two-dimensional ring in systems described by the Dirac equation
quant-phK. Bakke, Claudio Furtado
In this contribution, we propose a new model for studying the confinement of a spin-half particle to a two-dimensional quantum ring in systems described by the Dirac equation by introducing a new minimal coupling into the Dirac equation. We show that the introduction of this new minimal coupling into the Dirac equation yields a generalization of the two-dime
Daniel Mohler, R. M. Woloshyn
We present a calculation of the spectrum of low-lying D and D_s mesons calculated on 2+1 flavor configurations with Clover-Wilson quarks generated by the PACS-CS collaboration. S- and P-wave states are explored for pion masses down to 156MeV, including some excited states. As a benchmark, a calculation of the low-lying charmonium spectrum is performed. While
Zhibin Lin, Huashan Li, Alberto Franceschetti, Mark T. Lusk
First-order perturbation theory and many-body Green function analysis are used to quantify the influence of size, surface reconstruction and surface treatment on exciton transport between small silicon quantum dots. Competing radiative processes are also considered in order to determine how exciton transport efficiency is influenced. The analysis shows that
Joseph P. Conlon
We calculate the interaction potential between D5 and anti-D5 branes wrapping distant but homologous 2-cycles. The interaction potential is logarithmic in the separation radius and does not decouple at infinity. We show that logarithmic backreaction is generic for 5-branes wrapping distant but homologous 2-cycles, and we argue that this destabilises models o
Aldo-Hilario Cruz-Cota, Teresita Ramirez-Rosas
\noindent Given a Riemann surface $M$, the \emph{complexity} of a branched cover of $M$ to the Riemann sphere $S^2$, of degree $d$ and with branching set of cardinality $n \geq 3$, is defined as $d$ times the hyperbolic area of the complement of its branching set in $S^2$. A branched cover $p \colon M \to S^2$ of degree $d$ is \emph{simple} if the cardinalit
Tanmoy Bhattacharya, Vincenzo Cirigliano, Saul D. Cohen, Alberto Filipuzzi
Scalar and tensor interactions were once competitors to the now well-established V-A structure of the Standard Model weak interactions. We revisit these interactions and survey constraints from low-energy probes (neutron, nuclear, and pion decays) as well as collider searches. Currently, the most stringent limit on scalar and tensor interactions arise from 0
J. Gerssen, D. J. Wilman, L. Christensen
We have used the VIMOS integral field spectrograph to map the emission line properties in a sample of 24 star forming galaxies selected from the SDSS database. In this data paper we present and describe the sample, and explore some basic properties of SDSS galaxies with resolved emission line fields. We fit the Halpha+[NII] emission lines in each spectrum to
A. Raichoor, S. Andreon
The dependence of galaxy star formation activity on environment - especially in clusters - at high redshift is still poorly understood, as illustrated by the still limited number of z>1.4 clusters on the one hand, and by the still debated star formation-density relation at high redshift on the other hand. The zphot~2.2 JKCS041 cluster allows to probe such en
A. Sesana
I review our current understanding of massive black hole (MBH) formation and evolution along the cosmic history. After a brief introductory overview of the relevance of MBHs in the hierarchical structure formation paradigm, I discuss the main viable channels for seed BH formation at high redshift and for their subsequent mass growth and spin evolution. The e
Rouven Essig, Eder Izaguirre, Jared Kaplan, Jay G. Wacker
We consider a comprehensive set of simplified models that contribute to final states with top and bottom quarks at the LHC. These simplified models are used to create minimal search strategies that ensure optimal coverage of new heavy flavor physics involving the pair production of color octets and triplets. We provide a set of benchmarks that are representa
The Hubble Space Telescope Cluster Supernova Survey: VI. The Volumetric Type Ia Supernova Rate
astro-ph.COK. Barbary, G. Aldering, R. Amanullah, M. Brodwin
We present a measurement of the volumetric Type Ia supernova (SN Ia) rate out to z ~ 1.6 from the Hubble Space Telescope Cluster Supernova Survey. In observations spanning 189 orbits with the Advanced Camera for Surveys we discovered 29 SNe, of which approximately 20 are SNe Ia. Twelve of these SNe Ia are located in the foregrounds and backgrounds of the clu
Valentino Gonzalez, Rychard Bouwens, Ivo Labbe, Garth Illingworth
We use the ultra-deep HUDF09 and the deep ERS data from the HST WFC3/IR camera, along with the wide area Spitzer/IRAC data from GOODS-S to derive SEDs of star-forming galaxies from the rest-frame UV to the optical over a wide luminosity range (M_1500 ~ -21 to M_1500 ~ -18) from z ~ 7 to z ~ 4. The sample contains ~ 400 z ~ 4, ~ 120 z ~ 5, ~ 60 z ~ 6, and 36
Baojiu Li, George Efstathiou
In attempts to explain dark energy, a number of models have been proposed in which the formation of large-scale structure depends on the local environment. These models are highly non-linear and difficult to analyse analytically. N-body simulations have therefore been used to study their non-linear evolution. Here we extend excursion set theory to incorporat
R. J. Geretshauser, R. Speith, W. Kley
In the framework of the coagulation scenario, kilometre-sized planetesimals form by subsequent collisions of pre-planetesimals of sizes from centimetre to hundreds of metres. Pre-planetesimals are fluffy, porous dust aggregates, which are inhomogeneous owing to their collisional history. Planetesimal growth can be prevented by catastrophic disruption in pre-
Hans A. Winther, David F. Mota, Baojiu Li
We investigate the environment dependence of dark matter halos in the symmetron modified gravity scenario. The symmetron is one of three known mechanisms for screening a fifth-force and thereby recovering General Relativity in dense environments. The effectiveness of the screening depends on both the mass of the object and the environment it lies in. Using h
Z. L. Du, H. N. Wang
The concept of degree of similarity (η) is proposed to quantitatively describe the similarity of a parameter (e.g. the maximum amplitude Rmax) of a solar cycle relative to a referenced one, and the prediction method of similar cycles is further developed. For two parameters, the solar minimum (Rmin) and rising rate (βa), which can be directly measured a few
D. Aristizabal Sierra
In the standard seesaw model, finite corrections to the neutrino mass matrix arise from one-loop self-energy diagrams mediated by heavy neutrinos. We discuss the impact that these corrections may have on the different entries of the tree-level effective neutrino mass matrix, paying special attention to their dependence with the seesaw model parameters. We al
Christopher J. Leininger, Dan Margalit
A closed Teichmuller geodesic in the moduli space M_g of Riemann surfaces of genus g is called L-short if it has length at most L/g. We show that, for any L > 0, there exist e_2 > e_1 > 0, independent of g, so that the L-short geodesics in M_g all lie in the intersection of the e_1-thick part and the e_2-thin part. We also estimate the number of L-short geod
Shuichi Tasaki, Shigeru Ajisaka, Felipe Barra
The derivation of macroscopic irreversible dynamics of nonequilibrium systems from microscopic equations was recently revisited from the point of view of infinitely extended quantum systems. Here we have briefly reviewed the $C^*$ algebra and its application to equilibrium systems as well as introduced some recent results on NESS. In addition, we have demons
Comment on "Pressure dependence of wall relaxation in polarized He^3 gaseous cells." by W. Zheng, H. Gao, Q. Ye, and Y.Zhang
physics.atom-phA. Petukhov, J. Chastagnier, C. M. Swank, R. Golub
The authors have demonstrated a strong linear pressure dependence of the longitudinal relaxation time for He^3 at room and cryogenic temperatures in a given experimental setup. They offer a theoretical explanation of the effect based on diffusion theory in the bulk and an unusual boundary condition. We question the physical basis of the boundary condition an
Matthew L. Johnson
We investigate when the product of two Hecke eigenforms for Γ_1(N) is again a Hecke eigenform. In this paper we prove that the product of two normalized eigenforms for Γ_1(N), of weight greater than 1, is an eigenform only 61 times, and give a complete list. Duke [Duk99] and Ghate [Gha00] independently proved that with eigenforms for SL_2(Z), there are only
A Distributed Power Control and Transmission Rate Allocation Algorithm over Multiple Channels
math.DSThemistoklis Charalambous
In this paper, we consider multiple channels and wireless nodes with multiple transceivers. Each node assigns one transmitter at each available channel. For each assigned transmitter the node decides the power level and data rate of transmission in a distributed fashion, such that certain Quality of Service (QoS) demands for the wireless node are satisfied.
Lithium in the Upper Centaurus Lupus and Lower Centaurus Crux Subgroups of Scorpius-Centaurus
astro-ph.SREric J. Bubar, Marc Schaeuble, Jeremy R. King, Eric E. Mamajek
We utilize spectroscopically derived model atmosphere parameters and the \ion{Li}{1} $\lambda6104$ subordinate line and the $\lambda6708$ doublet to derive lithium abundances for 12 members of the Upper-Centaurus Lupus (UCL) and Lower-Centaurus Crux (LCC) subgroups of the Scorpius Centaurus OB Association. The results indicate any intrinsic Li scatter in our
Topological flatness of local models for ramified unitary groups. II. The even dimensional case
math.AGBrian D. Smithling
Local models are schemes, defined in terms of linear-algebraic moduli problems, which give étale-local neighborhoods of integral models of certain p-adic PEL Shimura varieties defined by Rapoport and Zink. In the case of a unitary similitude group whose localization at Q_p is ramified, quasi-split GU_n, Pappas has observed that the original local models are
J. J. Hamlin, M. Janoschek, R. E. Baumbach, B. D. White
We report magnetization and specific heat measurements down to 2 K and electrical resistivity down to millikelvin temperatures on polycrystalline samples of the non-centrosymmetric compound Yb2Co12P7. In addition to the previously reported ferromagnetic ordering of the cobalt sub-lattice at T_C = 136 K we find a magnetic transition below T_M = 5 K that is li
P. Benaglia, N. Casco, S. Cichowolski, A. Cillis
The European Space Agency (ESA) will inaugurate its third Deep Space Antenna (DSA 3) by the end of 2012. DSA 3 will be located in Argentina near the city of Malarg"ue in the Mendoza province. While the instrument will be primarily dedicated to communications with interplanetary missions, the characteristics of its antenna and receivers will also enable s
Nissim Fraija, Magdalena Gonzalez, Willian Lee
GRB 980923 was one of the brightest bursts observed by the Burst and Transient Source Experiment (BATSE). Previous studies have detected two distinct components in addition to the main prompt episode, which is well described by a Band function. The first of these is a tail with a duration of 400s, while the second is a high-energy component lasting 2s. After
Michael G. Opferman, Rob D. Coalson, David Jasnow, Anton Zilman
Mixtures of nanoparticles and polymer-like objects are encountered in many nanotechnological applications and biological systems. We study the behavior of grafted polymer layers decorated by nanoparticles that are attracted to the polymers using lattice gas based mean field theory and accompanying coarse-grained Brownian dynamics simulations. We find that th
Jürgen Knödlseder
With the advent of a new generation of telescopes (INTEGRAL, Fermi, H.E.S.S., MAGIC, VERITAS, MILAGRO) and the prospects of planned observatories such as CTA or HAWC, gamma-ray astronomy is becoming an integral part of modern astrophysical research. Analysing gamma-ray data is still a major challenge, and today relies on a large diversity of tools and softwa
Tim van Erven, Peter Grünwald, Wouter M. Koolen, Steven de Rooij
Most methods for decision-theoretic online learning are based on the Hedge algorithm, which takes a parameter called the learning rate. In most previous analyses the learning rate was carefully tuned to obtain optimal worst-case performance, leading to suboptimal performance on easy instances, for example when there exists an action that is significantly bet
Symmetry of uniaxial global Landau-de Gennes minimizers in the theory of nematic liquid crystals
math.APDuvan Henao, Apala Majumdar
We study uniaxial energy-minimizers within the Landau-de Gennes theory for nematic liquid crystals on a three-dimensional spherical droplet subject to homeotropic boundary conditions. We work in the low-temperature regime and show that uniaxial energy-minimizers necessarily have the structure of the well-studied radial-hedgehog solution in the low-temperatur
Spin Lifetime in Small Electron Spin Ensembles Measured by Magnetic Resonance Force Microscopy
cond-mat.mes-hallKin Chung Fong, Micheal R. Herman, Palash Banerjee, Denis V. Pelekhov
Magnetic Resonance Force Microscopy can enable nanoscale imaging of spin lifetime. We report temperature dependent measurements of the spin correlation time $τ_m$ of the statistical fluctuations of the spin polarization---the spin noise---of ensembles containing $\sim 100$ electron spins by this technique. Magneto-mechanical relaxation due to spin-cantilever
Volodymyr Makarov, Ihor Demkiv
Positive polynomial operator that approximates Urison operator, when integration domain is a "regular triangle" is investigated. We obtain Bernstein Polynomials as a particular case.
Shlomo Dado, Arnon Dar
Recently the OPERA collaboration reported a measurement of a superluminal speed of muon neutrinos travelling through the Earth's crust between their production site at CERN and their detection site under Gran Sasso, ~730 km away. The measurement was based on the assumption that the pulse shape of the neutrinos from the decay of parent mesons produced in
Elena Kleiman
Many packing, scheduling and covering problems that were previously considered by computer science literature in the context of various transportation and production problems, appear also suitable for describing and modeling various fundamental aspects in networks optimization such as routing, resource allocation, congestion control, etc. Various combinatori
Ayhan Gunaydin
We give description of rational solutions of polynomial-equations.
Discovery of a Be/X-ray pulsar binary and associated supernova remnant in the Wing of the SMC
astro-ph.SRV. Hénault-Brunet, L. M. Oskinova, M. A. Guerrero, W. Sun
We report on a new Be/X-ray pulsar binary located in the Wing of the Small Magellanic Cloud (SMC). The strong pulsed X-ray source was discovered with the Chandra and XMM-Newton X-ray observatories. The X-ray pulse period of 1062 s is consistently determined from both Chandra and XMM-Newton observations, revealing one of the slowest rotating X-ray pulsars kno
Inclusive distributions in p-p collisions at LHC energies compared with an adjusted DPMJET-III model with chain fusion
hep-phF. Bopp, J. Ranft
A DPMJET-III model (DPMJET-III-2011) with chain fusion adjusted to include energy.dependent parameters is used to calculate inclusive distributions in p-p collisions at LHC energies. Presented are charged hadrons rapidity distributions, transverse momentum distributions, multiplicity distributions as well as multiplicities at mid-rapidity as function of the
Chun-Kit Lai, Ka-Sing Lau, Hui Rao
We study the structure of the digit sets ${\mathcal D}$ for the integral self-similar tiles $T(b,{\mathcal{D}})$ (we call such ${\mathcal D}$ a {\it tile digit set} with respect to $b$). So far the only available classes of such tile digit sets are the complete residue sets and the product-forms. Our investigation here is based on the spectrum of the mask po
The Role of Polytetrahedral Structures in the Elongation and Rupture of Gold Nanowires
cond-mat.mtrl-sciChristopher R. Iacovella, William R. French, Brandon G. Cook, Paul R. C. Kent
We report comprehensive high-accuracy molecular dynamics simulations using the ReaxFF forcefield to explore the structural changes that occur as Au nanowires are elongated, establishing trends as a function of both temperature and nanowire diameter. Our simulations and subsequent quantitative structural analysis reveal that polytetrahedral structures (e.g.,
A. Tiribocchi, G. Gonnella, D. Marenduzzo, E. Orlandini
Blue phases (BPs) are liquid crystals made up by networks of defects, or disclination lines. While existing phase diagrams show a striking variety of competing metastable topologies for these networks, very little is known as to how to kinetically reach a target structure, or how to switch from one to the other, which is of paramount importance for devices.
S. I. Dejak, P. M. Lushnikov, Yu. N. Ovchinnikov, I. M. Sigal
We consider the phenomenon of collapse in the critical Keller-Segel equation (KS) which models chemotactic aggregation of micro-organisms underlying many social activities, e.g. fruiting body development and biofilm formation. Also KS describes the collapse of a gas of self-gravitating Brownian particles. We find the fluctuation spectrum around the collapsin
Eleonora Nagali, Simone Felicetti, Pierre-Louis de Assis, Vincenzo D'Ambrosio
The extraction of information from a quantum system unavoidably implies a modification of the measured system itself. It has been demonstrated recently that partial measurements can be carried out in order to extract only a portion of the information encoded in a quantum system, at the cost of inducing a limited amount of disturbance. Here we analyze experim
David M. Straub
A suitably broken U(2)^3 symmetry acting on the first two generations of quarks and squarks is studied as a natural generalization of the Minimal Flavour Violation principle to the case of a hierarchical squark spectrum. A definite correlation emerges between the meson mixing amplitudes in the K, B(d) and B(s) systems which can resolve the current tension in
Rieuwert J. Blok, Stephen Gagola
In 1974 Orin Chein discovered a new family of Moufang loops which are now called Chein loops. Such a loop can be created from any group $W$ together with $\mathbb{Z}_2$ by a variation on a semi-direct product. We study these loops in the case where $W$ is a Coxeter group and show that it has what we call a Chein-Coxeter system, a small set of generators of o
R. Percacci
I discuss the notion of asymptotic safety and possible applications to quantum field theories of gravity and matter.
Oleg Borisenko, Gennaro Cortese, Roberto Fiore, Mario Gravina
We investigate the critical properties of two-dimensional Z(N) vector models for N larger than 4. In particular, critical points of the two phase transitions are located and some critical indices are determined. We study also the behavior of the helicity modulus and the dependence of the critical points on N.
Mariola Klusek-Gawenda, Antoni Szczurek
The cross section for exclusive $π^+π^-$ and $π^0π^0$ meson pairs production in peripheral ultrarelativistic heavy-ion collisions is calculated at the energy available at the CERN Large Hadron Collider, i.e., $\sqrt{s_{NN}}=3.5$ TeV. The cross section for elementary $γγ\toππ$ process is calculated with the help of the pQCD Brodsky-Lepage approach with the di
A. Pastore, K. Bennaceur, D. Davesne, J. Meyer
Nuclear effective interactions are often modelled by simple analytical expressions such as the Skyrme zero-range force. This effective interaction depends on a limited number of parameters that are usually fitted using experimental data obtained from doubly magic nuclei. It was recently shown that many Skyrme functionals lead to the appearance of instabiliti
T. Yankova, D. Huvonen, S. Muhlbauer, D. Schmidiger
We review a strategy for targeted synthesis of large single crystal samples of prototype quantum magnets for inelastic neutron scattering experiments. Four case studies of organic copper halogenide S=1/2 systems are presented. They are meant to illustrate that exciting experimental results pertaining to forefront many-body quantum physics can be obtained on
Pedro Ontaneda
We discuss whether the strict hyperbolization process of Charney and Davis can be done smoothly.
Christopher A. Francisco, Jeffrey Mermin, Jay Schweig
We introduce the notion of Q-Borel ideals: ideals which are closed under the Borel moves arising from a poset Q. We study decompositions and homological properties of these ideals, and offer evidence that they interpolate between Borel ideals and arbitrary monomial ideals.
Review of canonical scenarios of gamma-ray jet emission from recent HE-VHE observations of 3C279 with MAGIC
astro-ph.HEK. Berger, J. Becerra González, G. Bonnoli, L. Maraschi
In 2006 the stand-alone MAGIC-I telescope discovered very high energy gamma-ray emission from 3C279. Additional observations were triggered when the source entered an exceptionally bright optical state in January 2007 and the Fermi space telescope measured a bright GeV gamma-ray flare in December 2008 until April 2009. While the complete January 2007 dataset
Svante Janson
Consider an election where N seats are distributed among parties with proportions p_1,...,p_m of the votes. We study, for the common divisor and quota methods, the asymptotic distribution, and in particular the mean, of the seat excess of a party, i.e. the difference between the number of seats given to the party and the (real) number Np_i that yields exact
Exploring the very high energy gamma-ray emission (E > 100 GeV) of the hard spectrum Fermi sources 1FGL J2001.1+4351 and B3-2247+381 with MAGIC
astro-ph.HEK. Berger, G. Giavitto, E. Lindfors, L. Takalo
MAGIC, a stereoscopic cherenkov telescope array, sensitive to gamma-rays between 50 GeV and several tens of TeV, is ideally suited to observe promising Fermi LAT sources with a hard γ-ray spectrum. Here we discuss the discovery of very high energy gamma-ray (VHE, E > 100 GeV) emission from the Fermi LAT sources 1FGL J2001.1+4351 and B3-2247+381 with MAGIC. 1
Otmar Venjakob
Almost simultaneously Ritter and Weiss arXiv:1004.2578 on the one hand and Kakde arXiv:1008.0142 on the other hand gave a proof of the non-commutative Iwasawa main conjecture over totally real fields for the Tate motive under the assumption that a certain $μ$-invariant vanishes as has been conjectured also by Iwasawa. In this notes we compare both approaches
Stefano Capitani, Michele Della Morte, Georg von Hippel, Bastian Knippschild
We present the first results of an ongoing effort to determine the lattice scale on the N_f=2 CLS lattice ensembles via the mass of the Ω baryon. Results from different methods are compared, and various sources of systematic uncertainty are discussed.
Kangjun Seo, Li Han, C. A. R. Sá de Melo
We develop a theory for interacting fermions in the presence of spin-orbit coupling and Zeeman fields, and show that many new superfluids phases, which are topological in nature, emerge. Depending on values of spin-orbit coupling, Zeeman fields, and interactions, initially gapped s-wave superfluids acquire p-wave, d-wave, f-wave and higher angular momentum c