February 2009 arXiv papers — page 15
Showing 1,401–1,500 of 4,929 papers
Feng Qi, Bai-Ni Guo
In this paper, we sharpen and generalize Carlson's double inequality for the arc cosine function.
Francesco Sannino
We study the nonperturbative dynamics of nonsupersymmetric asymptotically free gauge theories with fermionic matter in distinct representations of the SO(N) and Sp(2N) gauge groups. We use different analytic methods to unveil the associated conformal windows for the relevant matter representations. We propose a direct test for confronting and establishing th
S. J. Curran, M. T. Whiting
In this paper we further explore the implications that this has for the currently popular consensus that it is the orientation of the circumnuclear obscuring torus which determines whether absorption is present along our sight-line. The fact that at logL > 23 W/Hz, both type-1 and type-2 objects exhibit a 50% probability of detection, suggests that this is n
Jeffrey E. McClintock, Ronald A. Remillard
In astronomy, the problem of black holes is arguably second in importance only to the problem of cosmology. A current frontier in black hole research is the measurement of spin. During the past three years, the spins of several stellar-mass black holes in X-ray binaries have been measured via two techniques: fitting the X-ray continuum spectrum and modeling
John F. Dobson, Evan MacA. Gray
A superparamagnetic nanoparticle (SPN) is a nanometre-sized piece of a material that would, in bulk, be a permanent magnet. In the SPN the individual atomic spins are aligned via Pauli effects into a single giant moment that has easy orientations set by shape or magnetocrystalline anisotropy. Above a size-dependent blocking temperature $T_{b}(V,τ_{obs})$, th
Todd J. Henry, David G. Monet, Paul D. Shankland, Mark J. Reid
We discuss the opportunities for astronomical discovery via ground-based astrometry carried out in the United States during the 2010-2020 decade. We describe imminent scientific breakthroughs that can be achieved at both classic astrometric scales -- narrow angle astrometry done by individual groups and large A*Omega astrometry carried out by consortia. The
Henry H. Hsieh, David Jewitt, Yanga R. Fernandez
We present the determination of the geometric R-band albedos of two main-belt comet nuclei based on data from the Spitzer Space Telescope and a number of ground-based optical facilities. For 133P/Elst-Pizarro, we find an albedo of p_R=0.05+/-0.02 and an effective radius of r_e=1.9+/-0.3 km (estimated semi-axes of a~2.3 km and b~1.6 km). For 176P/LINEAR, we f
Aida Wofford
In general, HII regions do not show clear signs of self-enrichment in products from massive stars (M > 8 M_sun). In order to explore why, I modeled the contamination with Wolf-Rayet star ejecta of metal-poor (Z=0.001) HII regions, ionised either by a 10^6 M_sun cluster of coeval stars (cluster 1), or a cluster resulting from continuous star formation at a ra
S. J. May, T. S. Santos, A. Bhattacharya
(LaNiO3)n/(SrMnO3)2 superlattices were grown using ozone-assisted molecular beam epitaxy. In situ reflection high energy electron diffraction and x-ray scattering has been used to characterize the structural properties of the superlattices, which are strained to the SrTiO3 substrates. The superlattices exhibit excellent crystallinity and interfacial roughnes
High Redshift Radio Galaxies: Laboratories for Massive Galaxy and Cluster Formation in the early Universe
astro-ph.COG. Miley, C. Carilli, G. B. Taylor, C. de Breuck
High redshift radio galaxies are among the largest, most luminous, most massive, and most beautiful objects in the Universe. They are generally identified from their radio emission, thought to be powered by accretion of matter onto supermassive black holes in the nuclei of their host galaxies. Observations show that they are energetic sources of radiation th
Explicit formulas for currents at branching long lines and for maximum of current amplitudes
physics.class-phNikolai Dokuchaev
A system of 'telegrapher's' equations for a number of long lines joined into a network is studied. Explicit formulas for Fourier transforms of current and voltage are derived. These formulas are very suitable for computer application as well as for the analytical study of processes o networks. As an example, the availability of formulas aids the
Hiroya Yamaguchi, Satoru Katsuda
We present the X-ray observation of Vela shrapnel B with the XIS on board the Suzaku satellite. The shrapnel is one of several ejecta fragment-like features protruding beyond the primary blast wave shock front of the Vela supernova remnant. The spectrum of shrapnel B is well-represented by a single-temperature thin-thermal plasma in a non-equilibrium ionizat
C. L. Carilli, S. Myers, P. Appleton, F. Bertoldi
When, and how, did the first galaxies and supermassive black holes (SMBH) form, and how did they reionization the Universe? First galaxy formation and cosmic reionization are among the last frontiers in studies of cosmic structure formation. We delineate the detailed astrophysical probes of early galaxy and SMBH formation afforded by observations at centimet
R Brent Tully, L Rizzi, E J Shaya, H M Courtois
A database can be accessed on the web at http://edd.ifa.hawaii.edu that was developed to promote access to information related to galaxy distances. The database has three functional components. First, tables from many literature sources have been gathered and enhanced with links through a distinct galaxy naming convention. Second, comparisons of results both
Jennifer M. Stone, Ellen G. Zweibel
We consider the scenario of a magnetic field orthogonal to a front separating two media of different temperatures and densities, such as cold and warm interstellar gas, in a 2-D plane-parallel geometry. A linear stability analysis is performed to assess the behavior of both evaporation and condensation fronts when subject to incompressible, corrugational per
Daniel R. Wik, Craig L. Sarazin, Alexis Finoguenov, Kyoko Matsushita
The brightest cluster radio halo known resides in the Coma cluster of galaxies. The relativistic electrons producing this diffuse synchrotron emission should also produce inverse Compton emission that becomes competitive with thermal emission from the ICM at hard X-ray energies. Thus far, claimed detections of this emission in Coma are controversial (Fusco-F
Zhifan Chen, Alfred Z. Msezane
Photoionization of the Ce$^{3+}$ - Ce$^{4+}$ process has been studied using the random phase approximation with exchange method in the energy region 100-150 eV. Comparison of our results with the recent measurement [Müller {\it et al}, Phys. Rev. Lett. {\bf 101}, 133001 (2008)] confirms the suppression effect of the carbon cage in the endohedral fullerene Ce
Modeling thalamocortical cell: impact of Ca2+ channel distribution and cell geometry on firing pattern
q-bio.NCReza Zomorrodi, Helmut Kroger, Igor Timofeev
The influence of calcium channel distribution and geometry of the thalamocortical cell upon its tonic firing and the low threshold spike (LTS) generation was studied in a 3-compartment model, which represents soma, proximal and distal dendrites as well as in multi-compartment model using the morphology of a real reconstructed neuron. Using an uniform distrib
T. Sato, T. -S. H. Lee
The development of a dynamical model for investigating the nucleon resonances using the reactions of meson production from πN, γN, N(e,e'), and N(ν,{\it l}) reactions is reviewed. The results for the Δ(1232) state are summarized and discussed. The progress in investigating higher mass nucleon resonances is reported.
Chiral Dynamics in Photo-Pion Physics: Theory, Experiment, and Future Studies at the HI$\gamma$S Facility
nucl-exAron M. Bernstein, Mohammad W. Ahmed, Sean Stave, Ying K. Wu
A review of photo-pion experiments on the nucleon in the near threshold region is presented. Comparisons of the results are made with the predictions of the low energy theorems of QCD calculated using chiral perturbation theory (ChPT) which is based on the spontaneous breaking of chiral symmetry as well as its explicit breaking due to the finite quark masses
Stimulated Raman scattering in an optical parametric oscillator based on periodically poled MgO-doped stoichiometric LiTaO3
physics.opticsT-H. My, O. Robin, O. Mhibik, C. Drag
The evolution versus pump power of the spectrum of a singly resonant optical parametric oscillator based on an MgO-doped periodically poled stoichiometric lithium tantalate crystal is observed. The onset of cascade Raman lasing due to stimulated Raman scattering in the nonlinear crystal is analyzed. Spurious frequency doubling and sum-frequency generation ph
Volker Mattick, Claus-Peter Wirth
We present the first formal algebraic specification of a hypertext reference model. It is based on the well-known Dexter Hypertext Reference Model and includes modifications with respect to the development of hypertext since the WWW came up. Our hypertext model was developed as a product model with the aim to automatically support the design process and is e
Michael Zwolak, Johan Lagerqvist, Massimiliano Di Ventra
Ionic transport in nanopores is a fundamentally and technologically important problem in view of its occurrence in biological processes and its impact on novel DNA sequencing applications. Using microscopic calculations, here we show that ion transport may exhibit strong nonlinearities as a function of the pore radius reminiscent of the conductance quantizat
Kevin Fleming, Nicholas Pippenger
We study random surfaces constructed by glueing together $N/k$ filled $k$-gons along their edges, with all $(N-1)!! = (N-1)(N-3)...3\cdot 1$ pairings of the edges being equally likely. (We assume that lcm $\{2,k\}$ divides $N$.) The Euler characteristic of the resulting surface is related to the number of cycles in a certain random permutation of $\{1, ...,
T. R. Hurd, Zhuowei Zhou
Spread options are a fundamental class of derivative contract written on multiple assets, and are widely used in a range of financial markets. There is a long history of approximation methods for computing such products, but as yet there is no preferred approach that is accurate, efficient and flexible enough to apply in general models. The present paper int
Spectroscopic Analysis of the White Dwarf KUV 02196+2816: A New Unresolved DA+DB Degenerate Binary
astro-ph.SRM. -M. Limoges, P. Bergeron, Pierre Dufour
A spectroscopic analysis of the DBA (or DAB) white dwarf KUV 02196+2816 is presented. The observed hydrogen and helium line profiles are shown to be incompatible with model spectra calculated under the assumption of a homogeneous hydrogen and helium chemical composition. In contrast, an excellent fit to the optical spectrum of KUV 02196+2816 can be achieved
Alberto Alzati, GianMario Besana
Very ampleness criteria for rank 2 vector bundles over smooth, ruled surfaces over rational and elliptic curves are given. The criteria are then used to settle open existence questions for some special threefolds of low degree.
Cheol-Hwan Park, Feliciano Giustino, Catalin D. Spataru, Marvin L. Cohen
We present first-principles calculations of the linewidths of low-energy quasiparticles in n-doped graphene arising from both the electron-electron and the electron-phonon interactions. The contribution to the electron linewidth arising from the electron-electron interactions vary significantly with wavevector at fixed energy; in contrast, the electron-phono
William Y. C. Chen, Svetlana Poznanovik, Catherine H. Yan, Arthur L. B. Yang
We propose a major index statistic on 01-fillings of moon polyominoes which, when specialized to certain shapes, reduces to the major index for permutations and set partitions. We consider the set F(M, s; A) of all 01-fillings of a moon polyomino M with given column sum s whose empty rows are A, and prove that this major index has the same distribution as th
Ming-Tang Chen, Chao-Te Li, Yuh-Jing Hwang, Homin Jiang
The Y. T. Lee Array for Microwave Background (AMiBA) has reported the first science results on the detection of galaxy clusters via the Sunyaev Zel'dovich effect. The science objectives required small reflectors in order to sample large scale structures (20') while interferometry provided modest resolutions (2'). With these constraints, we design
Claus-Peter Wirth
Using a human-oriented formal example proof of the (lim+) theorem, i.e. that the sum of limits is the limit of the sum, which is of value for reference on its own, we exhibit a non-permutability of beta-steps and delta+-steps (according to Smullyan's classification), which is not visible with non-liberalized delta-rules and not serious with further liber
Maria Manosas, Alessandro Mossa, Nuria Forns, Josep Maria Huguet
We investigate irreversibility and dissipation in single molecules that cooperatively fold/unfold in a two state manner under the action of mechanical force. We apply path thermodynamics to derive analytical expressions for the average dissipated work and the average hopping number in two state systems. It is shown how these quantities only depend on two par
Dynamic force spectroscopy of DNA hairpins. I. Force kinetics and free energy landscapes
cond-mat.stat-mechAlessandro Mossa, Maria Manosas, Nuria Forns, Josep Maria Huguet
We investigate the thermodynamics and kinetics of DNA hairpins that fold/unfold under the action of applied mechanical force. We introduce the concept of the molecular free energy landscape and derive simplified expressions for the force dependent Kramers-Bell rates. To test the theory we have designed a specific DNA hairpin sequence that shows two-state coo
W. B. Vasantha Kandasamy
In this book, we introduce the notion of Smarandache special definite algebraic structures. We can also call them equivalently as Smarandache definite special algebraic structures. These new structures are defined as those strong algebraic structures which have in them a proper subset which is a weak algebraic structure. For instance, the existence of a semi
Miroslav Englis, Harald Upmeier
For a real symmetric domain $G_{\mathbb R}/K_{\mathbb R}$, with complexification $G_{\mathbb C}/K_{\mathbb C}$, we introduce the concept of "star-restriction" (a real analogue of the "star-products" for quantization of Kähler manifolds) and give a geometric construction of the $G_{\mathbb R}$-invariant differential operators yielding its asym
Elisabetta A. Matsumoto, Randall D. Kamien
Recent experiments have exploited elastic instabilities in membranes to create complex patterns. However, the rational design of such structures poses many challenges, as they are products of nonlinear elastic behavior. We pose a simple model for determining the orientational order of such patterns using only linear elasticity theory which correctly predicts
Xinfu Chen, Danielle Hilhorst, Elisabeth Logak
We consider a mass conserved Allen-Cahn equation $u_t=Δu+ \e^{-2} (f(u)-\eλ(t))$ in a bounded domain with no flux boundary condition, where $\eλ(t)$ is the average of $f(u(\cdot,t))$ and $-f$ is the derivative of a double equal well potential. Given a smooth hypersurface $γ_0$ contained in the domain, we show that the solution $u^\e$ with appropriate initial
K. C. Hsieh, P. C. Frisch, J. Giacalone, J. R. Jokipii
We present an alternate interpretation of recent STEREO/STE observations that were originally attributed to energetic neutral atoms (ENA) from the heliosheath. The signal attributed to the diffuse ENA source instead shows the characteristics of a point source. We point out that the peak intensity seen by STEREO/STE is centered at the ecliptic longitude of th
A. Lazarian, S. Boldyrev, C. Forest, J. Sarff
A combination of observation, theory, modeling, and laboratory plasma experiments provides a multifaceted approach to develop a much greater understanding of how magnetic fields arise in galactic settings and how these magnetic fields mediate important processes that affect the dynamics, distribution, and composition of galactic plasmas. An important emphasi
Ellen Zweibel, Jeremy Goodman, Hantao Ji, Alex Lazarian
The major questions relevant to star and planet formation are: What controls the rate, efficiency, spatial clustering, multiplicity, and initial mass function of star formation, now and in the past? What are the major feedback mechanisms through which star formation affects its environment? What controls the formation and orbital parameters of planets, espec
Stephan Kreutzer
Algorithmic meta-theorems are general algorithmic results applying to a whole range of problems, rather than just to a single problem alone. They often have a "logical" and a "structural" component, that is they are results of the form: every computational problem that can be formalised in a given logic L can be solved efficiently on every cl
Felix Bruemmer, Joerg Jaeckel
Minicharged particles arise naturally in extensions of the Standard Model with a kinetic mixing term between the ordinary electromagnetic U(1) and an extra "hidden sector" U(1). In this note we study the compatibility of these particles with the existence of magnetic monopoles. We find that angular momentum quantization allows only certain combinatio
Claus-Peter Wirth
We study the combination of the following already known ideas for showing confluence of unconditional or conditional term rewriting systems into practically more useful confluence criteria for conditional systems: Our syntactical separation into constructor and non-constructor symbols, Huet's introduction and Toyama's generalization of parallel close
Indistinguishable photons from the resonance fluorescence of a single quantum dot in a microcavity
quant-phSerkan Ates, Sven Markus Ulrich, Stephan Reitzenstein, Andreas Loeffler
We demonstrate purely resonant continuous-wave optical laser excitation to coherently prepare an excitonic state of a single semiconductor quantum dot (QDs) inside a high quality pillar microcavity. As a direct proof of QD resonance fluorescence, the evolution from a single emission line to the characteristic Mollow triplet10 is observed under increasing pum
Jihn E. Kim, Hans Peter Nilles
We discuss the idea that the model-independent (MI) axion of string theory is the source of quintessential dark energy. The scenario is completed with a composite QCD axion from hidden sector squark condensation that could serve as dark matter candidate. The mechanism relies on the fact that the hidden sector anomaly contribution to the composite axion is mu
M. Harada, C. Sasaki
The presence of baryonic matter leads to the mixing between transverse $\rho$ and $a_1$ mesons through a set of $\omega\rho a_1$-type interactions, which results in the modification to the dispersion relation. We show that a clear enhancement of the vector spectral function appears below $\sqrt{s}=m_\rho$ for small three-momenta of the $\rho$ meson, and thus
P. Ila, W. Gosnold, P. Jagam, G. I. Lykken
A combination of several sources including: radiogenic heating, processes of mantle and core formation and differentiation, delayed radiogenic heating, earthquakes, and tidal friction account for the surface heat flux in the Earth. Radiogenic heating is of much interest in various fields of geosciences. Inferences from recent experiments with reactor antineu
Christoffer Flensburg
A series of previous papers develops a dipole model in initial state impact parameter space that includes subleading effects such as running alpha strong, unitarity, confinement and saturation. Here some recent work is presented, where the model is applied to a new set of data: vector meson production in photon-proton, DVCS and t-dependence in elastic proton
Matthew R. Templeton, Margarita Karovska
We carried out a new and sensitive search for long-period variability in the prototype of the Mira class of long-period pulsating variables, o Ceti (Mira A), the closest and brightest Mira variable. We conducted this search using an unbroken light curve from 1902 to the present, assembled from the visual data archives of five major variable star observing or
Diana T. Stoeva
In this paper we consider perturbation of X_d-Bessel sequences, X_d-frames, Banach frames, atomic decompositions and X_d-Riesz bases in separable Banach spaces. Equivalence between some perturbation conditions is investigated.
Silvia Mollerach
These lectures review some of the techniques used to analyze the arrival direction distribution of Cosmic Rays, and some relevant results on the field.
Dmitri Uzdensky, Cary Forest, Hantao Ji, Richard Townsend
This is a white paper submitted to the Stars and Stellar Evolution (SSE) Science Frontier Panel (SFP) of the NRC's 2010 Astronomy and Astrophysics Decadal Survey. The white paper is endorsed by the NSF Physics Frontier Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas (CMSO).
L. F. Rodriguez, Y. Gomez, L. Guzman
Planetary nebulae (and in general any photoionized region) can be classified as ionization-bounded or density-bounded. It is important to determine in which case is the planetary nebula studied to be able to estimate from nebular observations, for example, the total rate of ionizing photons produced by the central star. In this paper we present a simple obse
Aris L. Moustakas, K Raj Kumar, Giuseppe Caire
Linear receivers are considered as an attractive low-complexity alternative to optimal processing for multi-antenna MIMO communications. In this paper we characterize the performance of MMSE MIMO receivers in the limit of large antenna numbers in the presence of channel correlations. Using the replica method, we generalize our results obtained in arXiv:0810.
D. Uzdensky, J. Arons, S. Balbus, E. Blackman
This is a white paper submitted to the Stars and Stellar Evolution (SSE) Science Frontier Panel (SFP) of the NRC's Astronomy and Astrophysics 2010 Decadal Survey. The white paper is endorsed by the American Physical Society's (APS) Topical Group on Plasma Astrophysics (GPAP).
Temperature dependence of the bulk energy gap in underdoped Bi-2212: Evidence for the mean-field superconducting transition
cond-mat.supr-conV. M. Krasnov
Understanding of the puzzling phenomenon of high temperature superconductivity requires reliable spectroscopic information about temperature dependence of the bulk electronic density of states. Here I present a comprehensive analysis of $T-$evolution of bulk electronic spectra in Bi-2212 obtained by Intrinsic Tunneling Spectroscopy on small mesa structures.
A. J. Webster
In the first part to this paper\cite{part1} it was shown how a simple Magnetohydrodynamic model could be used to determine the stability of a Tokamak plasma's edge to a Peeling (External Kink) mode. Stability was found to be determined by the value of $Δ'$, a normalised measure of the discontinuity in the radial derivative of the radial perturbation
Stefan Scheel, Stefan Yoshi Buhmann
In this article, we review the principles of macroscopic quantum electrodynamics and discuss a variety of applications of this theory to medium-assisted atom-field coupling and dispersion forces. The theory generalises the standard mode expansion of the electromagnetic fields in free space to allow for the presence of absorbing bodies. We show that macroscop
A. J. Webster, C. G. Gimblett
The rapid deposition of energy by Edge Localised Modes (ELMs) onto plasma facing components, is a potentially serious issue for large Tokamaks such as ITER and DEMO. The trigger for ELMs is believed to be the ideal Magnetohydrodynamic Peeling-Ballooning instability, but recent numerical calculations have suggested that a plasma equilibrium with an X-point -
Fernando Haas, Padma Kant Shukla
The quantum Zakharov system in three-spatial dimensions and an associated Lagrangian description, as well as its basic conservation laws are derived. In the adiabatic and semiclassical case, the quantum Zakharov system reduces to a quantum modified vector nonlinear Schrödinger (NLS) equation for the envelope electric field. The Lagrangian structure for the r
Amin Coja-Oghlan
Let F be a uniformly distributed random k-SAT formula with n variables and m clauses. We present a polynomial time algorithm that finds a satisfying assignment of F with high probability for constraint densities m/n<(1-eps_k)2^k\ln(k)/k, where eps_k->0. Previously no efficient algorithm was known to find solutions with non-vanishing probability beyond m/n=1.
Stefano Pasetto, Cesare Chiosi
The spatial distribution of galaxies in the Local Group (LG) is the footprint of its formation mechanism and the gravitational interactions among its members and the external massive galaxies or galaxy groups. Recently, Pasetto & Chiosi (2007), using a 3D-geometrical description of the spatial distribution of all the members of the LG (not only the satellite
T. Jarlborg
The mechanism of spin-phonon coupling (SPC) and possible consequencies for the properties of high-$T_C$ copper oxides are presented. The results are based on ab-initio LMTO band calculations and a nearly free-electron (NFE) model of the band near $E_F$. Many observed properties are compatible with SPC, as for the relation between doping and $\vec{q}$ for spi
Manual of BlackMax, a black-hole event generator with rotation, recoil, split branes, and brane tension
hep-phDe-Chang Dai, Cigdem Issever, Eram Rizvi, Glenn Starkman
This is the users manual of the black-hole event generator BlackMax, which simulates the experimental signatures of microscopic and Planckian black-hole production and evolution at proton-proton, proton-antiproton and electron-positron colliders in the context of brane world models with low-scale quantum gravity. The generator is based on phenomenologically
Pavol Severa
We extend Tamarkin's formality of the little disk operad to the framed little disk operad.
S. Mühlbauer, C. Pfleiderer, P. Böni, M. Laver
The morphology of the superconducting flux line lattice (FLL) of Nb comprises gradual variations with various lock-in transitions and symmetry breaking rotations. We report a comprehensive small-angle neutron scattering study of the FLL in an ultra-pure single crystal of Nb as a function of the orientation of the applied magnetic field. We attribute the gene
Bjorn Poonen
The problem of deciding, given a complex variety X, a point x in X, and a subvariety Z of X, whether there is an automorphism of X mapping x into Z is proved undecidable. Along the way, we prove the undecidability of a version of Hilbert's tenth problem for systems of polynomials over Z defining an affine Q-variety whose projective closure is smooth.
J. Vijande, G. Krein, A. Valcarce
We perform a quark model calculation of the quarkonia $b\overline{b}$ and $c\overline{c}$ spectra using smooth and sudden string breaking potentials. The screening parameter is scale dependent and can be related to an effective running gluon mass that has a finite infrared fixed point. A temperature dependence for the screening mass is motivated by lattice Q
Mehmet Tekkoyun
The goal of this paper is to present Euler-Lagrange and Hamiltonian equations on R2n which is a model of para-Kaehlerian manifolds of constant J-sectional curvature. In conclusion, some differential geometrical and physical results on the related mechanic systems have been given.
Jussi Behrndt, Mark M. Malamud, Hagen Neidhardt
In this paper the scattering matrix of a scattering system consisting of two selfadjoint operators with finite dimensional resolvent difference is expressed in terms of a matrix Nevanlinna function. The problem is embedded into an extension theoretic framework and the theory of boundary triplets and associated Weyl functions for (in general nondensely define
Mehmet Tekkoyun
In this study, we conclude the vertical, complete and horizontal lifts of Frenet formulas given by (1) and defined on space R3 to its tangent space TR3 = R6.
Jonathan M Aspden, Jacques Vanneste
The elliptical instability of a rotating stratified fluid is examined in the regime of small Rossby number and order-one Burger number corresponding to rapid rotation and strong stratification. The Floquet problem describing the linear growth of disturbances to an unbounded, uniform-vorticity elliptical flow is solved using exponential asymptotics. The resul
Zoltan Jurek, Gyula Faigel
We study the local distortion of the atomic structure in small biological samples illuminated by x-ray free electron laser (XFEL) pulses. We concentrate on the effect of inhomogenities: heavy atoms in a light matrix and non-homogeneous spatial distribution of atoms. In biological systems we find both. Using molecular-dynamics type modeling it is shown that t
Vitor Cardoso, Oscar J. C. Dias
At high energy densities any quantum field theory is expected to have an effective hydrodynamic description. When combined with the gravity/gauge duality an unified picture emerges, where gravity itself can have a formal holographic hydrodynamic description. This provides a powerful tool to study black holes in a hydrodynamic setup. We study the stability of
M. Mapelli, B. Moore
Giant low surface brightness galaxies (GLSBs), such as Malin 1, have unusually large and flat discs. Their formation is a puzzle for cosmological simulations in the cold dark matter scenario. We suggest that GLSBs might be the final product of the dynamical evolution of collisional ring galaxies. In fact, our simulations show that, approximately 0.5-1.5 Gyr
Andrzej M. Frydryszak
Entanglement of four qubit pure states defined by the $η$-trigonometric functions is studied. We analyze the behavior of two recently proposed symmetric entanglement monotones on the chosen $n=4$ qubit states .
Model of circular polarization dependence on Mn delta-layer position in LED heterostructures with InGaAs/GaAs quantum well
cond-mat.mes-hallD. V. Khomitsky
A simple model of circular polarization dependence on Mn delta-layer position in LED heterostructures with InGaAs/GaAs quantum well is proposed, being able to explain quite accurately recent fascinating experimental results [S.V. Zaitsev, et al., Physica E (2009), doi:10.1016/j.physe.2008.11.003]. The model emphasizes the role of position-dependent exchange
L. Sunil Chandran, Mathew C. Francis, Rogers Mathew
The boxicity of a graph G, denoted as box(G) is defined as the minimum integer t such that G is an intersection graph of axis-parallel t-dimensional boxes. A graph G is a k-leaf power if there exists a tree T such that the leaves of the tree correspond to the vertices of G and two vertices in G are adjacent if and only if their corresponding leaves in T are
Deaf, Dumb, and Chatting Robots, Enabling Distributed Computation and Fault-Tolerance Among Stigmergic Robot
cs.MAYoann Dieudonné, Shlomi Dolev, Franck Petit, Michael Segal
We investigate ways for the exchange of information (explicit communication) among deaf and dumb mobile robots scattered in the plane. We introduce the use of movement-signals (analogously to flight signals and bees waggle) as a mean to transfer messages, enabling the use of distributed algorithms among the robots. We propose one-to-one deterministic movemen
Vinko Zlatić, Hrvoje Štefančić
We show how reciprocal arcs significantly influence the structural organization of Wikipedias, online encyclopedias. It is shown that random addition of reciprocal arcs in the static network cannot explain the observed reciprocity of Wikipedias. A model of Wikipedia growth based on preferential attachment and on information exchange via reciprocal arcs is pr
Eran Palti
We study intersecting D6-branes in Calabi-Yau manifolds that are smooth hypersurfaces in weighted projective spaces. We develop the techniques for calculating intersection numbers between special Lagrangian sub-manifolds defined as fixed loci of anti-holomorphic involutions. We present global Pati-Salam and MSSM-like models that are supersymmetric up to a de
Ursula Schroeter, Elke Scheer
Transport through a point contact is accurately modelled by assigning to the junction an ensemble of independent transport channels with possibly different transmissions. We here argue that for a series of two contacts, coherently coupled across an island, the transport channels are different from the ensembles that would describe each contact taken as stand
Clive Emary
We describe a method for calculating the counting statistics of electronic transport through nanoscale devices with both sequential and cotunneling contributions. The method is based upon a perturbative expansion of the von Neumann equation in Liouvillian space, with current cumulants calculated from the resulting nonMarkovian master equation without further
Vinko Zlatić, Hrvoje Štefančić
Reciprocal arcs represent the lowest order cycle possible to find in directed graphs without self-loops. Representing also a measure of feed-back between vertices, it is interesting to understand how reciprocal arcs influence other properties of complex networks. In this paper we focus on influence of reciprocal arcs on vertex degree distribution and degree
Armen Bagdasaryan
We consider the basic features of complex dynamical and control systems. Special attention is paid to the problems of synthesis of dynamical models of complex systems, construction of efficient control models, and to the development of simulation techniques. We propose an approach to the synthesis of dynamic models of complex systems that integrates expert k
M. Mapelli, M. Colpi, L. Zampieri
Low-metallicity (Z <~ 0.05 Zsun) massive (>~40 Msun) stars might end their life by directly collapsing into massive black holes (BHs, 30 <~ m_BH/Msun <~ 80). More than ~10^5 massive BHs might have been generated via this mechanism in the metal-poor ring galaxy Cartwheel, during the last ~10^7 yr. We show that such BHs might power most of the ultra-luminous X
Franz Wegner
Bodies of density one half (of the fluid in which they are immersed) that can float in all orientations are investigated. It is shown that expansions starting from and deforming the (hyper)sphere are possible in arbitrary dimensions and allow for a large manifold of solutions: One may either (i) expand r(n)+r(-n) in powers of a given difference r(u)-r(-u), (
C. Baldovin Saavedra, M. Audard, G. Duchêne, M. Güdel
We present the Chandra High Energy Transmission Grating Spectrometer (HETGS) and Keck observations of HDE 245059, a young weak-lined T Tauri star (WTTS), member of the pre-main sequence group in the Lambda Orionis Cluster. Our high spatial resolution, near-infrared observations with Keck reveal that HDE 245059 a binary separated by 0.87". Based on this n
C. Bell, S. Harashima, Y. Hikita, H. Y. Hwang
The electronic transport properties of a series of LaAlO_3 / SrTiO_3 interfaces were investigated, and a systematic thickness dependence of the sheet resistance and magnetoresistance was found for constant growth conditions. This trend occurs above the critical thickness of four unit cells, below which the LaAlO_3 / SrTiO_3 interface is not conducting. A dra
Dong-Ling Deng, Zi-Sui Zhou, Jing-Ling Chen
In the celebrated paper [J. Phys. A: Math. Gen. 37, 1775 (2004)], D. Collins and N. Gisin presented for the first time a three setting Bell inequality (here we call it CG inequality for simplicity) which is relevant to the Clauser-Horne-Shimony-Holt (CHSH) inequality. Inspired by their brilliant ideas, we obtained some multi-setting tight Bell inequalities,
U. Amaldi, S. Braccini, A. Citterio, K. Crandall
We propose an innovative fast-cycling accelerator complex conceived and designed to exploit at best the properties of accelerated ion beams for hadrontherapy. A cyclinac is composed by a cyclotron, which can be used also for other valuable medical and research purposes, followed by a high gradient linear accelerator capable to produce ion beams optimized for
Temperature-dependent mechanisms for the dynamics of protein-hydration waters: a molecular dynamics simulation study
cond-mat.softMichael Vogel
Molecular dynamics simulations are performed to study the temperature-dependent dynamics and structures of the hydration shells of elastin-like and collagen-like peptides. For both model peptides, it is consistently observed that, upon cooling, the mechanisms for water dynamics continuously change from small-step diffusive motion to large-step jump motion, t
Lélia Blin, Maria Gradinariu Potop-Butucaru, Stephane Rovedakis
In this paper we design and prove correct a fully dynamic distributed algorithm for maintaining an approximate Steiner tree that connects via a minimum-weight spanning tree a subset of nodes of a network (referred as Steiner members or Steiner group) . Steiner trees are good candidates to efficiently implement communication primitives such as publish/subscri
J. Greiner, S. E. Boggs, G. DiCocco, K. T. Freese
Nuclear physics offers us a powerful tool: using nuclear resonance absorption lines to infer the physical conditions in astrophysical settings which are otherwise difficult to deduce. Present-day technology provides an increase in sensitivity over previous gamma-ray missions large enough to utilize this tool for the first time. The most exciting promise is t
Design principle of multi-cluster and desynchronized states in oscillatory media via nonlinear global feedback
nlin.PSYasuaki Kobayashi, Hiroshi Kori
A theoretical framework is developed for a precise control of spatial patterns in oscillatory media using nonlinear global feedback, where a proper form of the feedback function corresponding to a specific pattern is predicted through the analysis of a phase diffusion equation with global coupling. In particular, feedback functions that generate the followin
Comment on "Existence of Einstein static universes and their stability in fourth-order theories of gravity"
gr-qcJohn Miritzis
It is argued that the solution space of the equation determining the class of $f(R)$ theories which admit an Einstein static universe should be broadened by including the algebraic roots.
F. Bouchy, C. Moutou, D. Queloz, the CoRoT Exoplanet Science Team
Radial Velocity follow-up is essential to establish or exclude the planetary nature of a transiting companion as well as to accurately determine its mass. Here we present some elements of an efficient Doppler follow-up strategy, based on high-resolution spectroscopy, devoted to the characterization of transiting candidates. Some aspects and results of the ra
P. A. Baikov, K. G. Chetyrkin, A. V. Smirnov, V. A. Smirnov
We compute the form factors of the photon-quark-anti-quark vertex and the effective vertex of a Higgs boson and two gluons to three-loop order within massless perturbative Quantum Chromodynamics. These results provide building blocks for many third-order cross sections. Furthermore, this is the first calculation of complete three-loop vertex corrections.
Xiang Wu, Xiang-Yang Liu, Ning Du, Gang-Qin Xu
In this letter, we adopt a new approach combining theoretical modeling with silk stretching measurements to explore the mystery of the structures between silkworm and spider silks, leading to the differences in mechanical response against stretching. Hereby the typical stress-strain profiles are reproduced by implementing the newly discovered and verified &#
John Augustine, Qi Han, Philip Loden, Sachin Lodha
We introduce a variant of the capacitated vehicle routing problem that is encountered in sensor networks for scientific data collection. Consider an undirected graph $G=(V \cup \{\mathbf{sink}\},E)$. Each vertex $v \in V$ holds a constant-sized reading normalized to 1 byte that needs to be communicated to the $\mathbf{sink}$. The communication protocol is de