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Arxiv.org
by Renan Cabrera; Denys I. Bondar; Herschel A. Rabitz
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The relativistic Wigner function for spin 1/2 particles is the subject of active research due to diverse applications. However, further progress is hindered by the fabulous complexity of the integro-differential equations of motion. We simplify these equations to partial differential equations of the Dirac type that are not only well suited for numerical computation, but also posses a well defined classical limit in a manifestly covariant form.
Source: http://arxiv.org/abs/1107.5139v2
Arxiv.org
by Hiroshi Miki; Satoshi Tsujimoto; Luc Vinet; Alexei Zhedanov
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An interpretation of the multiple Meixner polynomials of the first kind is provided through an infinite Lie algebra realized in terms of the creation and annihilation operators of a set of independent oscillators. The model is used to derive properties of these orthogonal polynomials.
Source: http://arxiv.org/abs/1203.0357v1
Arxiv.org
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We analyse the structure of imprecise Markov chains and study their convergence by means of accessibility relations. We first identify the sets of states, so-called minimal permanent classes, that are the minimal sets capable of containing and preserving the whole probability mass of the chain. These classes generalise the essential classes known from the classical theory. We then define a class of extremal imprecise invariant distributions and show that they are uniquely determined by the...
Source: http://arxiv.org/abs/1203.3088v2
Arxiv.org
by Takeshi Araki; Julian Heeck; Jisuke Kubo
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Augmenting the Standard Model by three right-handed neutrinos allows for an anomaly-free gauge group extension G_max = U(1)_(B-L) x U(1)_(L_e-L_mu) x U(1)_(L_mu-L_tau). While simple U(1) subgroups of G_max have already been discussed in the context of approximate flavor symmetries, we show how two-zero textures in the right-handed neutrino Majorana mass matrix can be enforced by the flavor symmetry, which is spontaneously broken very economically by singlet scalars. These zeros lead to two...
Source: http://arxiv.org/abs/1203.4951v2
Arxiv.org
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We consider the effect of the wind and the dissipation on the nonlinear stages of the modulational instability. By applying a suitable transformation, we map the forced/damped Nonlinear Schr\"odinger (NLS) equation into the standard NLS with constant coefficients. The transformation is valid as long as |{\Gamma}t| \ll 1, with {\Gamma} the growth/damping rate of the waves due to the wind/dissipation. Approximate rogue wave solutions of the equation are presented and discussed. The results...
Source: http://arxiv.org/abs/1203.4735v1
Arxiv.org
by K. T. Schmitt; K. L. Jones; A. Bey; S. H. Ahn; D. W. Bardayan; J. C. Blackmon; S. M. Brown; K. Y. Chae; K. A. Chipps; J. A. Cizewski; K. I. Hahn; J. J. Kolata; R. L. Kozub; J. F. Liang; C. Matei; M. Matoš; D. Matyas; B. Moazen; C. Nesaraja; F. M. Nunes; P. D. O'Malley; S. D. Pain; W. A. Peters; S. T. Pittman; A. Roberts; D. Shapira; J. F. Shriner Jr; M. S. Smith; I. Spassova; D. W. Stracener; A. N. Villano; G. L. Wilson
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The best examples of halo nuclei, exotic systems with a diffuse nuclear cloud surrounding a tightly-bound core, are found in the light, neutron-rich region, where the halo neutrons experience only weak binding and a weak, or no, potential barrier. Modern direct reaction measurement techniques provide powerful probes of the structure of exotic nuclei. Despite more than four decades of these studies on the benchmark one-neutron halo nucleus Be-11, the spectroscopic factors for the two bound...
Source: http://arxiv.org/abs/1203.3081v2
Arxiv.org
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Baryon number cumulants are invaluable tools to diagnose the primordial stage of heavy ion collisions if they can be measured. In experiments, however, proton number cumulants have been measured as substitutes. In fact, proton number fluctuations are further modified in the hadron phase and different from those of baryon number. We show that the isospin distribution of nucleons at kinetic freezeout is binomial and factorized. This leads to formulas that express the baryon number cumulants...
Source: http://arxiv.org/abs/1107.2755v2
Arxiv.org
by Claude Brezinski; Michela Redivo-Zaglia
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In this paper, we consider the particular case of the general rational Hermite interpolation problem where only the value of the function is interpolated at some points, and where the function and its first derivatives agree at the origin. Thus, the interpolants constructed in this way possess a Pad\'e--type property at 0. Numerical examples show the interest of the procedure. The interpolation procedure can be easily modified to introduce a partial knowledge on the poles and the zeros of the...
Source: http://arxiv.org/abs/1107.4854v3
Arxiv.org
by L. Dorame; S. Morisi; E. Peinado; Alma D. Rojas; J. W. F. Valle
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A class of discrete flavor-symmetry-based models predicts constrained neutrino mass matrix schemes that lead to specific neutrino mass sum-rules (MSR). One of these implies in a lower bound on the effective neutrinoless double beta mass parameter, even for normal hierarchy neutrinos. Here we propose a new model based on the S4 flavor symmetry that leads to the new neutrino mass sum-rule and discuss how to generate a nonzero value for the reactor mixing angle indicated by recent experiments, and...
Source: http://arxiv.org/abs/1203.0155v1
Arxiv.org
by Octavio Miramontes; Og DeSouza; Diego Hernández; Eliane Ceccon
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We measured mobility patterns that describe walking trajectories of individual Me'Phaa peasants searching and collecting fuelwood in the forests of "La Monta\~na de Guerrero" in Mexico. These one-day excursions typically follow a mixed pattern of nearly-constant steps when individuals displace from their homes towards potential collecting sites and a mixed pattern of steps of different lengths when actually searching for fallen wood in the forest. Displacements in the searching phase...
Source: http://arxiv.org/abs/1203.0971v1
Arxiv.org
by Vasily Galkin
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The original F5 algorithm introduced by Faug\`ere is formulated for any homogeneous polynomial set input. The correctness of output is shown for any input that terminates the algorithm, but the termination itself is proved only for the case of input being regular polynomial sequence. This article shows that algorithm correctly terminates for any homogeneous input without any reference to regularity. The scheme contains two steps: first it is shown that if the algorithm does not terminate it...
Source: http://arxiv.org/abs/1203.2402v3
Arxiv.org
by Morishige Yoneda; Masaaki Niwa; Mitsuya Motohashi
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We have constructed a theory of dual canonical formalism to study the quantum competing systems. In such a system, as the relationship between current and voltage of each, we assumed the duality conditions. We considered competing system of two types. One type of these system are composed of the sandwich structure by SC(superconductor)/SI(superinsulator)/SC junction, and its dual junction is consists of the sandwich structure by SI/SC/SI junction. Another one type of these system is consists of...
Source: http://arxiv.org/abs/1203.3281v3
Arxiv.org
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We analyze the evolution of the Gaussian discord between two resonant harmonic oscillators coupled to a common environment. For this, we use the same tools we applied before to fully characterize the evolution of the entanglement in this system [ Phys. Rev. Lett. 100 220401 (2008)]. The asymptotic value of Gaussian discord is obtained as a function of parameters characterizing the environment (temperature, couplings, etc.) and the initial state of the system (initial squeezing, initial purity,...
Source: http://arxiv.org/abs/1203.3819v1
Arxiv.org
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In complex systems, the interplay between nonlinear and stochastic dynamics, e.g., J. Monod's necessity and chance, gives rise to an evolutionary process in Darwinian sense, in terms of discrete jumps among attractors, with punctuated equilibrium, spontaneous random "mutations" and "adaptations". On an evlutionary time scale it produces sustainable diversity among individuals in a homogeneous population rather than convergence as usually predicted by a deterministic...
Source: http://arxiv.org/abs/1203.3554v2
Arxiv.org
by Ismael Fortuna; Gilberto L. Thomas; Rita M. C. de Almeida; Francois Graner
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We study the topology and geometry of two dimensional coarsening foams with arbitrary liquid fraction. To interpolate between the dry limit described by von Neumann's law, and the wet limit described by Marqusee equation, the relevant bubble characteristics are the Plateau border radius and a new variable, the e?ective number of sides. We propose an equation for the individual bubble growth rate as the weighted sum of the growth through bubble-bubble interfaces and through bubble-Plateau...
Source: http://arxiv.org/abs/1203.5834v2
Arxiv.org
by Ashwin Guha; Ambedkar Dukkipati
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In this paper we consider polynomial representability of functions defined over Z_{p^n}, where p is a prime and n is a positive integer. Our aim is to provide an algorithmic characterization that answers the decision problem: to determine whether a given function over Z_{p^n} is polynomially representable or not. The previous characterizations given by Carlitz (1964) and Kempner (1921) are existential in nature and only lead to an exhaustive search method, i.e. algorithm with complexity...
Source: http://arxiv.org/abs/1203.1122v3
Arxiv.org
by Kristoffer Arnsfelt Hansen; Rasmus Ibsen-Jensen; Peter Bro Miltersen
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Two standard algorithms for approximately solving two-player zero-sum concurrent reachability games are value iteration and strategy iteration. We prove upper and lower bounds of 2^(m^(Theta(N))) on the worst case number of iterations needed by both of these algorithms for providing non-trivial approximations to the value of a game with N non-terminal positions and m actions for each player in each position. In particular, both algorithms have doubly-exponential complexity. Even when the game...
Source: http://arxiv.org/abs/1007.1812v3
Arxiv.org
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In this paper, we shall establish a Dancer-type unilateral global bifurcation result for a class of quasilinear elliptic problems with sign-changing weight. Under some natural hypotheses on perturbation function, we show that $(\mu_k^\nu(p),0)$ is a bifurcation point of the above problems and there are two distinct unbounded continua, $(\mathcal{C}_{k}^\nu)^+$ and $(\mathcal{C}_{k}^\nu)^-$, consisting of the bifurcation branch $\mathcal{C}_{k}^\nu$ from $(\mu_k^\nu(p), 0)$, where $\mu_k^\nu(p)$...
Source: http://arxiv.org/abs/1203.3262v1
Arxiv.org
by Giambattista Giacomin; Khashayar Pakdaman; Xavier Pellegrin
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We study the dynamics of the large N limit of the Kuramoto model of coupled phase oscillators, subject to white noise. We introduce the notion of shadow inertial manifold and we prove their existence for this model, supporting the fact that the long term dynamics of this model is finite dimensional. Following this, we prove that the global attractor of this model takes one of two forms. When coupling strength is below a critical value, the global attractor is a single equilibrium point...
Source: http://arxiv.org/abs/1107.4501v2
Arxiv.org
by A. B. Goncharov; R. Kenyon
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We show that the dimer model on a bipartite graph on a torus gives rise to a quantum integrable system of special type - a cluster integrable system. The phase space of the classical system contains, as an open dense subset, the moduli space of line bundles with connections on the graph. The sum of Hamiltonians is essentially the partition function of the dimer model. Any graph on a torus gives rise to a bipartite graph on the torus. We show that the phase space of the latter has a Lagrangian...
Source: http://arxiv.org/abs/1107.5588v2
Arxiv.org
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We consider the synthesis of control policies for probabilistic systems, modeled by Markov decision processes, operating in partially known environments with temporal logic specifications. The environment is modeled by a set of Markov chains. Each Markov chain describes the behavior of the environment in each mode. The mode of the environment, however, is not known to the system. Two control objectives are considered: maximizing the expected probability and maximizing the worst-case probability...
Source: http://arxiv.org/abs/1203.1177v1
Arxiv.org
by K. Sabeeh; M. Tahir; A. MacKinnon
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We present a theoretical study of the electronic structure of magnetically modulated graphene. We consider monolayer graphene in the presence of a perpendicular magnetic field and a unidirectional weak magnetic modulation. The density of states and the bandwidth of the Dirac electrons in this system are determined. We have found magnetic Weiss oscillations in the bandwidth and the density of states. These oscillations are out of phase and larger in amplitude than the ones in the electrically...
Source: http://arxiv.org/abs/0804.4583v2
Arxiv.org
by P. Reig; J. M. Torrejon; P. Blay
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The discovery of very slow pulsations (Pspin=5560s) has solved the long-standing question of the nature of the compact object in the high-mass X-ray binary 4U 2206+54 but has posed new ones. According to spin evolutionary models in close binary systems, such slow pulsations require a neutron star magnetic field strength larger that the quantum critical value, suggesting the presence of a magnetar. We present the first XMM-Newton observations of 4U 2206+54 and investigate its spin evolution. We...
Source: http://arxiv.org/abs/1203.1490v2
Arxiv.org
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We analyze event-by-event fluctuations of the transverse momentum in relativistic heavy-ion collisions at RHIC in the framework based on the fluctuating Glauber-model initial conditions, event-by-event (3+1)-dimensional viscous hydrodynamics, and statistical hadronization. We use the scaled fluctuation measure < Delta p_Ti Delta p_Tj > / < < p_T >>. The identified "geometric" mechanism of generating the transverse-momentum fluctuations from the initial size...
Source: http://arxiv.org/abs/1203.1810v1
Arxiv.org
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We consider the differential cross section of electron-positron pair production by a high-energy photon in a strong Coulomb field close to the end of the electron or positron spectrum. When the momentum transfer largely exceeds the electron mass, the cross section is obtained analytically in a compact form. Coulomb corrections essentially modify the cross section even for moderate values of the nuclear charge number $Z$. In the same kinematical region, the angular distribution for bound-free...
Source: http://arxiv.org/abs/1203.2137v1
Recently developed series representations of the Boltzmann operator are used to obtain Quantum Mechanical results for the matrix elements, , of the imaginary time propagator. The calculations are done for two different potential surfaces: one of them is an Eckart Barrier and the other one is a double well potential surface. Numerical convergence of the series are investigated. Although the zeroth order term is sufficient at high temperatures, it does not lead to the correct saddle point...
Source: http://arxiv.org/abs/1203.5942v1
Arxiv.org
by Kelly R. Patton; Daniel E. Sheehy
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The induced intraspecies interactions among the majority species, mediated by the minority species, is computed for a population-imbalanced two-component Fermi gas. Although the Feshbach-resonance mediated interspecies interaction is dominant for equal populations, leading to singlet s-wave pairing, we find that in the strongly imbalanced regime the induced intraspecies interaction leads to p-wave pairing and superfluidity of the majority species. Thus, we predict that the observed spin-polaron...
Source: http://arxiv.org/abs/1203.6348v1
Arxiv.org
by Alejandro Adem; José Manuel Gómez
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In this note we study topological invariants of the spaces of homomorphisms Hom(\pi,G), where \pi\ is a finitely generated abelian group and G is a compact Lie group arising as an arbitrary finite product of the classical groups SU(r), U(q) and Sp(k).
Source: http://arxiv.org/abs/1203.5439v1
Arxiv.org
by E. Stonkutė; G. Tautvaišienė; B. Nordström; R. Ženovienė
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Galactic Archeology is a powerful tool for investigating the formation and evolution of the Milky Way. We use this technique to study kinematic groups of F- and G-stars in the solar neighbourhood. From correlations between orbital parameters, three new coherent groups of stars were recently identified and suggested to correspond to remnants of disrupted satellites. We determine detailed elemental abundances in stars belonging to one of these groups and compare their chemical composition with...
Source: http://arxiv.org/abs/1203.6199v1
Arxiv.org
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We briefly review the status of motivated beyond-the-MSSM phenomenology in the light of the LHC searches to date. In particular, we discuss the conceptual consequences of the exclusion bounds, of the hint for a Higgs boson at about 125 GeV, and of interpreting the excess of direct CP violation in the charm sector as a signal of New Physics. We try to go into the various topics in a compact way while providing a relatively rich list of references, with particular attention to the most recent...
Source: http://arxiv.org/abs/1203.6227v2
Arxiv.org
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A numerical method to integrate the time-dependent Hartree-Fock Bogoliubov (TDHFB) equations with Gogny interaction is proposed. The feasibility of the TDHFB code is illustrated by the conservation of the energy, particle numbers, and center-of-mass in the small amplitude vibrations of oxygen 20. The TDHFB code is applied to the isoscalar quadrupole and/or isovector dipole vibrations in the linear (small amplitude) region in oxygen isotopes (masses A = 18,20,22 and 24), titanium isotopes (A =...
Source: http://arxiv.org/abs/1203.6174v1
Arxiv.org
by A. Verdini; R. Grappin; R. Pinto; M. Velli
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We present a mechanism for the formation of the low frequency 1/f magnetic spectrum based on numerical solutions of a shell reduced-MHD model of the turbulent dynamics inside the sub-Alfv\'enic solar wind. We assign reasonably realistic profiles to the wind speed and the density along the radial direction, and a radial magnetic field. Alfv\'en waves of short periodicity (600 s) are injected at the base of the chromosphere, penetrate into the corona and are partially reflected, thus triggering a...
Source: http://arxiv.org/abs/1203.6219v2
Arxiv.org
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We study, in the framework of open quantum systems, the geometric phase acquired by a uniformly accelerated two-level atom undergoing nonunitary evolution due to its coupling to a bath of fluctuating vacuum electromagnetic fields in the multipolar scheme. We find that the phase variation due to the acceleration can be in principle observed via atomic interferometry between the accelerated atom and the inertial one, thus providing an evidence of the Unruh effect.
Source: http://arxiv.org/abs/1203.5869v1
Arxiv.org
by Jan O. Stenflo
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The Sun's magnetic field is structured over a range of scales that span approximately seven orders of magnitudes, four of which lie beyond the resolving power of current telescopes. Here we have used a Hinode SOT/SP deep mode data set for the quiet-sun disk center in combination with constraints from the Hanle effect to derive scaling laws that describe how the magnetic structuring varies from the resolved scales down to the magnetic diffusion limit, where the field ceases to be frozen-in. The...
Source: http://arxiv.org/abs/1203.6011v1
Arxiv.org
by M. Gennaro; A. Bik; W. Brandner; A. Stolte; B. Rochau; H. Beuther; D. Gouliermis; J. Tackenberg; N. Kudryavtseva; B. Hussmann; F. Schuller; Th. Henning
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We have started a campaign to identify massive star clusters inside bright molecular bubbles towards the Galactic Center. The CN15/16/17 molecular complex is the first example of our study. The region is characterized by the presence of two young clusters, DB10 and DB11, visible in the NIR, an ultra-compact HII region identified in the radio, several young stellar objects visible in the MIR, a bright diffuse nebulosity at 8\mu m coming from PAHs and sub-mm continuum emission revealing the...
Source: http://arxiv.org/abs/1203.5786v1
Arxiv.org
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Let $A \subseteq E$ be an extension of Hopf algebras such that there exists a normal left $A$-module coalgebra map $\pi : E \to A$ that splits the inclusion. We shall describe the set of all coquasitriangular structures on the Hopf algebra $E$ in terms of the datum $(A, E, \pi)$ as follows: first, any such extension $E$ is isomorphic to a unified product $A \ltimes H$, for some unitary subcoalgebra $H$ of $E$ (\cite{am2}). Then, as a main theorem, we establish a bijective correspondence between...
Source: http://arxiv.org/abs/1203.2455v1
Arxiv.org
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Branching processes and Fleming-Viot processes are two main models in stochastic population theory. Incorporating an immigration in both models, we generalize the results of Shiga (1990) and Birkner et al. (2005) which respectively connect the Feller diffusion with the classical Fleming-Viot process and the alpha-stable continuous state branching process with the Beta(2-alpha, alpha)-generalized Fleming-Viot process. In a recent work, a new class of probability-measure valued processes, called...
Source: http://arxiv.org/abs/1203.2494v2
Arxiv.org
by Amir Houmansadr; Negar Kiyavash; Nikita Borisov
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Linking network flows is an important problem in intrusion detection as well as anonymity. Passive traffic analysis can link flows but requires long periods of observation to reduce errors. Active traffic analysis, also known as flow watermarking, allows for better precision and is more scalable. Previous flow watermarks introduce significant delays to the traffic flow as a side effect of using a blind detection scheme; this enables attacks that detect and remove the watermark, while at the...
Source: http://arxiv.org/abs/1203.2273v1
An extension and generalization of a recently presented approach for the analysis of Langevin-type stochastic processes in the presence of strong measurement noise is presented. For a stochastic process in N dimensions which is superimposed with strong, exponentially correlated, Gaussian distributed, measurement noise it is possible to extract the strength and the correlation functions of the noise as well as polynomial approximations of the drift and diffusion functions of the underlying...
Source: http://arxiv.org/abs/1203.2334v2
Arxiv.org
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We have investigated the transmission and reflection properties of structures incorporating left-handed materials with graded index of refraction. We present an exact analytical solution to Helmholtz' equation for a graded index profile changing according to a hyperbolic tangent function along the propagation direction. We derive expressions for the field intensity along the graded index structure, and we show excellent agreement between the analytical solution and the corresponding results...
Source: http://arxiv.org/abs/1203.2311v1
Arxiv.org
by Wesam Gabran; Chun-Hao Liu; Przemysław Pawełczak; Danijela Cabric
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Accurate estimation of licensed channel Primary User's (PU) temporal statistics is important for Dynamic Spectrum Access (DSA) systems. With accurate estimation of the mean duty cycle, u, and the mean off- and on-times of PUs, DSA systems can more efficiently assign PU resources to its subscribers, thus, increasing channel utilization. This paper presents a mathematical analysis of the accuracy of estimating u, as well as the PU mean off- and on-times, where the estimation accuracy is expressed...
Source: http://arxiv.org/abs/1203.2393v2
Arxiv.org
by A. S. Sanz; Y. Elran; P. Brumer
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The effect of chaotic bath dynamics on the decoherence of a quantum system is examined for the vibrational degrees of freedom of a diatomic molecule in a realistic, constant temperature collisional bath. As an example, the specific case of I$_2$ in liquid xenon is examined as a function of temperature, and the results compared with an integrable xenon bath. A crossover in behavior is found: the integrable bath induces more decoherence at low bath temperatures than does the chaotic bath, whereas...
Source: http://arxiv.org/abs/1203.4629v2
Arxiv.org
by Sandro Gallo; Matthieu Lerasle; Daniel Yasumasa Takahashi
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We derive explicit upper bounds for the $\bar{d}$-distance between a chain of infinite order and its canonical $k$-steps Markov approximation. Our proof is entirely constructive and involves a "coupling from the past" argument. The new method covers non necessarily continuous probability kernels, and chains with null transition probabilities. These results imply in particular the Bernoulli property for these processes.
Source: http://arxiv.org/abs/1107.4353v2
Arxiv.org
by B. Küng; C. Rössler; M. Beck; M. Marthaler; D. S. Golubev; Y. Utsumi; T. Ihn; K. Ensslin
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We present a low-temperature experimental test of the fluctuation theorem for electron transport through a double quantum dot. The rare entropy-consuming system trajectories are detected in the form of single charges flowing against the source-drain bias by using time-resolved charge detection with a quantum point contact. We find that these trajectories appear with a frequency that agrees with the theoretical predictions even under strong nonequilibrium conditions, when the finite bandwidth of...
Source: http://arxiv.org/abs/1107.4240v2
Arxiv.org
by F. K. Roepke; M. Kromer; I. R. Seitenzahl; R. Pakmor; S. A. Sim; S. Taubenberger; F. Ciaraldi-Schoolmann; W. Hillebrandt; G. Aldering; P. Antilogus; C. Baltay; S. Benitez-Herrera; S. Bongard; C. Buton; A. Canto; F. Cellier-Holzem; M. Childress; N. Chotard; Y. Copin; H. K. Fakhouri; M. Fink; D. Fouchez; E. Gangler; J. Guy; S. Hachinger; E. Y. Hsiao; C. Juncheng; M. Kerschhaggl; M. Kowalski; P. Nugent; K. Paech; R. Pain; E. Pecontal; R. Pereira; S. Perlmutter; D. Rabinowitz; M. Rigault; K. Runge;...
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The nearby supernova SN 2011fe can be observed in unprecedented detail. Therefore, it is an important test case for Type Ia supernova (SN Ia) models, which may bring us closer to understanding the physical nature of these objects. Here, we explore how available and expected future observations of SN 2011fe can be used to constrain SN Ia explosion scenarios. We base our discussion on three-dimensional simulations of a delayed detonation in a Chandrasekhar-mass white dwarf and of a violent merger...
Source: http://arxiv.org/abs/1203.4839v1
Arxiv.org
by E. Breedt; B. T. Gaensicke; J. Girven; A. J. Drake; C. M. Copperwheat; S. G. Parsons; T. R. Marsh
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We present phase-resolved spectroscopy of two new short period low accretion rate magnetic binaries, SDSSJ125044.42+154957.3 (Porb = 86 min) and SDSSJ151415.65+074446.5 (Porb = 89 min). Both systems were previously identified as magnetic white dwarfs from the Zeeman splitting of the Balmer absorption lines in their optical spectra. Their spectral energy distributions exhibit a large near-infrared excess, which we interpret as a combination of cyclotron emission and possibly a late type...
Source: http://arxiv.org/abs/1203.4711v1
Arxiv.org
by E. A. O'Brien; C. Voll
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We develop general formulae for the numbers of conjugacy classes and irreducible complex characters of finite p-groups of nilpotency class less than p. This allows us to unify and generalize a number of existing enumerative results, and to obtain new such results for generalizations of relatively free p-groups of exponent p. Our main tools are the Lazard correspondence and the Kirillov orbit method.
Source: http://arxiv.org/abs/1203.3050v1
Arxiv.org
by M. Arrayás; M. A. Fontelos; U. Kindelán
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We present the first analytical and numerical studies of the initial stage of the branching process based on an interface dynamics streamer model in the fully 3-D case. This model follows from fundamental considerations on charge production by impact ionization and balance laws, and leads to an equation for the evolution of the interface between ionized and non-ionized regions. We compare some experimental patterns with the numerically simulated ones, and give an explicit expression for the...
Source: http://arxiv.org/abs/1203.6790v1
Arxiv.org
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We consider two dimensional real-valued analytic potentials for the Schr\"odinger equation which are periodic over a lattice $L$. Under certain assumptions on the form of the potential and the lattice $L$, we can show there is a large class of analytic potentials which are Floquet rigid and dense in the set of $C^\infty(R^2/L)$ potentials. The result extends the work of Eskin et. al, in "On isospectral periodic potentials in $R^n$, II."
Source: http://arxiv.org/abs/1203.2901v1
Arxiv.org
by Lucas A. Cieza; Matthias R. Schreiber; Gisela A. Romero; Jonathan P. Williams; Alberto Rebassa-Mansergas; Bruno Merin
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As part of an ongoing program aiming to characterize a large number of Spitzer-selected transition disks (disks with reduced levels of near-IR and/or mid- IR excess emission), we have obtained (sub)millimeter wavelength photometry, high-resolution optical spectroscopy, and adaptive optics near-infrared imaging for a sample of 31 transition objects located in the Perseus, Taurus, and Auriga molecular clouds. We use these ground-based data to estimate disk masses, multiplicity, and accretion...
Source: http://arxiv.org/abs/1203.6849v1
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by Mirko Klukas; Bijan Sahamie
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We apply spectral sequences to derive both an obstruction to the existence of $n$-fold prolongations and a topological classification. Prolongations have been used in the literature in an attempt to prove that every Engel structure on $M\times\mathbb{S}^1$ with characteristic line field tangent to the fibers is determined by the contact structure induced on a cross section and the twisting of the Engel structure along the fibers. Our results show that this statement needs some modification: to...
Source: http://arxiv.org/abs/1107.5884v3
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by Arash Bodaghee; Farid Rahoui; John A. Tomsick; Jerome Rodriguez
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The Chandra High Resolution Camera observed the fields of five hard X-ray sources in order to help us obtain X-ray coordinates with sub-arcsecond precision. These observations provide the most accurate X-ray positions known for IGR J16393-4643 and for IGR J17091-3624. The obscured X-ray pulsar IGR J16393-4643 lies at R.A. (J2000) = 16:39:05.47, and Dec. = -46:42:13.0 (error radius of 0.6" at 90% confidence). This position is incompatible with the previously-proposed counterpart 2MASS...
Source: http://arxiv.org/abs/1203.0557v2
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by Z. Salman; E. Pomjakushina; V. Pomjakushin; A. Kanigel; K. Chashka; K. Conder; E. Morenzoni; T. Prokscha; K. Sedlak; A. Suter
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We present a detailed investigation of the magnetic and structural properties of magnetically doped 3D topological insulator Bi2Se3. From muon spin relaxation measurements in zero magnetic field, we find that even 5% Fe doping on the Bi site turns the full volume of the sample magnetic at temperatures as high as ~250 K. This is also confirmed by magnetization measurements. Two magnetic "phases" are identified; the first is observed between ~10-250 K while the second appears below ~10...
Source: http://arxiv.org/abs/1203.4850v1
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Dzhaparidze and Spreij [5] showed that the quadratic variation of a semimartingale can be approximated using a randomized periodogram. We show that the same approximation is valid for a special class of continuous stochastic processes. This class contains both semimartingales and non-semimartingales. The motivation comes partially from the recent work by Bender et al. [2], where it is shown that the quadratic variation of the log-returns determines the hedging strategy.
Source: http://arxiv.org/abs/1005.4349v2
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by Jacob van den Berg; Demeter Kiss
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Let $E$ be the set of edges of the $d$-dimensional cubic lattice $\mathbb{Z}^d$, with $d\geq2$, and let $t(e),e\in E$, be nonnegative values. The passage time from a vertex $v$ to a vertex $w$ is defined as $\inf_{\pi:v\rightarrow w}\sum_{e\in\pi}t(e)$, where the infimum is over all paths $\pi$ from $v$ to $w$, and the sum is over all edges $e$ of $\pi$. Benjamini, Kalai and Schramm [2] proved that if the $t(e)$'s are i.i.d. two-valued positive random variables, the variance of the passage time...
Source: http://arxiv.org/abs/1007.0849v2
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In this paper, a study of random times on filtered probability spaces is undertaken. The main message is that, as long as distributional properties of optional processes up to the random time are involved, there is no loss of generality in assuming that the random time is actually a randomized stopping time. This perspective has advantages in both the theoretical and practical study of optional processes up to random times. Applications are given to the stochastic behavior of processes up to...
Source: http://arxiv.org/abs/1007.1124v3
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by Guangxi Jin; Kun Cao; Guang-Can Guo; Lixin He
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"Magnetic ferroelectric" has been found in a wide range of spiral magnets. However, these materials all suffer from low critical temperatures, which are usually below 40 K, due to strong spin frustration. Recently, CuO has been found to be multiferroic at much higher ordering temperature ($\sim$ 230K). To clarify the origin of the high ordering temperature in CuO, we investigate the structural, electronic and magnetic properties of CuO via first-principles methods. We find that CuO...
Source: http://arxiv.org/abs/1007.2274v4
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by S. H. P. Alencar; J. Bouvier; F. M. Walter; C. Dougados; J. -F. Donati; R. Kurosawa; M. Romanova; X. Bonfils; G. H. R. A. Lima; S. Massaro; M. Ibrahimov; E. Poretti
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We analyze the photometric and spectroscopic variability of the classical T Tauri star V2129 Oph over several rotational cycles to test the dynamical predictions of magnetospheric accretion models. The photometric variability and the radial velocity variations in the photospheric lines can be explained by rotational modulation due to cold spots, while the radial velocity variations of the He I (5876 \AA) line and the veiling variability are due to hot spot rotational modulation. The hot and...
Source: http://arxiv.org/abs/1203.6331v1
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by Mário Jorge Dias Carneiro; Alexandre Rocha
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We prove that for the set of Exact Magnetic Lagrangians the property "There exist finitely many static classes for every cohomology class" is generic. We also prove some dynamical consequences of this property.
Source: http://arxiv.org/abs/1203.6095v1
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by S. R. Elliott; B. H. LaRoque; V. M. Gehman; M. F. Kidd; M. Chen
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We have examined the atomic theory behind recent constraints on the violation of the Pauli Exclusion Principle derived from experiments that look for x rays emitted from conductors while a large current is present. We also re-examine the assumptions underlying such experiments. We use the results of these studies to assess pilot measurements to develop an improved test of the Principle. We present an improved limit of $(1/2)\beta^2 < 2.6\times10^{-39}$ on the Pauli Exclusion Principle. This...
Source: http://arxiv.org/abs/1107.3118v2
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by J. de la Cruz Rodríguez; H. Socas-Navarro; M. Carlsson; J. Leenaarts
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The magnetic field of the quiet-Sun chromosphere remains a mystery for solar physicists. The reduced number of chromospheric lines are intrinsically hard to model and only a few of them are magnetically sensitive. In this work, we use a 3D numerical simulation of the outer layers of the solar atmosphere, to asses the reliability of non-LTE inversions, in this case applied to the Ca II 8542 \AA\ line. We show that NLTE inversions provide realistic estimates of physical quantities from synthetic...
Source: http://arxiv.org/abs/1203.4577v1
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by S. H. Lubow; R. G. Martin
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We describe a model for the long term evolution of a circumplanetary disk that is fed mass from a circumstellar disk and contains regions of low turbulence (dead zones). We show that such disks can be subject to accretion driven outbursts, analogous to outbursts previously modeled in the context of circumstellar disks to explain FU Ori phenomena. Circumplanetary disks around a proto-Jupiter can undergo outbursts for infall accretion rates onto the disks in the range ~10^{-9} to 10^{-7}...
Source: http://arxiv.org/abs/1203.6134v1
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by Daniel Kolbe; Martin Scheid; Jochen Walz
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Continuous-wave coherent radiation in the vacuum ultraviolet (VUV)wavelength region at 121 nm will be essential for future laser-cooling of trapped antihydrogen [1]. Cold antihydrogen will enable both tests of the fundamental symmetry between matter and antimatter at unprecedented experimental precision [2] and also experiments in antimatter gravity [3]. Another fascinating application of narrowband continuous laser radiation in the VUV is quantum information processing using single trapped...
Source: http://arxiv.org/abs/1203.2121v1
We discuss quantum electrodynamics emerging in the vacua with anisotropic scaling. Systems with anisotropic scaling were suggested by Horava in relation to the quantum theory of gravity. In such vacua the space and time are not equivalent, and moreover they obey different scaling laws, called the anisotropic scaling. Such anisotropic scaling takes place for fermions in bilayer graphene, where if one neglects the trigonal warping effects the massless Dirac fermions have quadratic dispersion....
Source: http://arxiv.org/abs/1203.1578v3
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by Rui Albuquerque
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We give a brief presentation of gwistor space, which is a new concept from G_2 geometry. Then we compute the characteristic torsion T^c of the gwistor space of an oriented Riemannian 4-manifold with constant sectional curvature k and deduce the condition under which T^c is \nabla^c-parallel; this allows for the classification of the G_2 structure with torsion and the characteristic holonomy according to known references. The case with the Einstein base manifold is envisaged.
Source: http://arxiv.org/abs/1107.5357v2
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by Gonzalo A. Alvarez; Alexandre M. Souza; Dieter Suter
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The loss of quantum information due to interaction with external degrees of freedom, which is known as decoherence, remains one of the main obstacles for large-scale implementations of quantum computing. Accordingly, different measures are being explored for reducing its effect. One of them is dynamical decoupling (DD) which offers a practical solution because it only requires the application of control pulses to the system qubits. Starting from basic DD sequences, more sophisticated schemes...
Source: http://arxiv.org/abs/1203.0252v1
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The Generalized Traveling Salesman Problem (GTSP) is a well-known combinatorial optimization problem with a host of applications. It is an extension of the Traveling Salesman Problem (TSP) where the set of cities is partitioned into so-called clusters, and the salesman has to visit every cluster exactly once. While the GTSP is a very important combinatorial optimization problem and is well studied in many aspects, the local search algorithms used in the literature are mostly basic adaptations...
Source: http://arxiv.org/abs/1005.5525v4
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by Cecilia Cavaterra; Elisabetta Rocca
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The present contribution investigates the well-posedness of a PDE system describing the evolution of a nematic liquid crystal flow under kinematic transports for molecules of different shapes. More in particular, the evolution of the {\em velocity field} $\ub$ is ruled by the Navier-Stokes incompressible system with a stress tensor exhibiting a special coupling between the transport and the induced terms. The dynamic of the {\em director field} $\bd$ is described by a variation of a parabolic...
Source: http://arxiv.org/abs/1107.3947v2
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by Silvio Franz; Giorgio Parisi; Federico Ricci-Tersenghi
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We consider the critical properties of points of continuous glass transition as one can find in liquids in presence of constraints or in liquids in porous media. Through a one loop analysis we show that the critical Replica Field Theory describing these points can be mapped in the $\phi^4$-Random Field Ising Model. We confirm our analysis studying the finite size scaling of the $p$-spin model defined on sparse random graph, where a fraction of variables is frozen such that the phase transition...
Source: http://arxiv.org/abs/1203.4849v3
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We prove a formal power series identity, relating the arithmetic sum-of-divisors function to commuting triples of permutations. This establishes a conjecture of Franklin T. Adams-Watters.
Source: http://arxiv.org/abs/1203.5079v1
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by Julian Sonner; Andrew G. Green
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The dynamical scaling of quantum critical systems in thermal equilibrium may be inherited in the driven steady-state, leading to universal out-of-equilibrium behaviour. This attractive notion has been demonstrated in just a few cases. We demonstrate how holography - a mapping between the quantum critical system and a gravity dual - provides an illuminating perspective and new results. Non-trivial out-of-equilibrium universality is particularly apparent in current noise, which is dual to Hawking...
Source: http://arxiv.org/abs/1203.4908v2
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Using analytical techniques and Langevin dynamics simulations, we investigate the dynamics of polymer translocation through a nanochannel embedded in two dimensions under an applied external field. We examine the translocation time for various ratio of the channel length $L$ to the polymer length $N$. For short channels $L\ll N$, the translocation time $\tau \sim N^{1+\nu}$ under weak driving force $F$, while $\tau\sim F^{-1}L$ for long channels $L\gg N$, independent of the chain length $N$....
Source: http://arxiv.org/abs/1203.5118v1
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by Pierpaolo Mastrolia; Edoardo Mirabella; Tiziano Peraro
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We present a semi-analytic method for the integrand reduction of one-loop amplitudes, based on the systematic application of the Laurent expansions to the integrand-decomposition. In the asymptotic limit, the coefficients of the master integrals are the solutions of a diagonal system of equations, properly corrected by counterterms whose parametric form is konwn a priori. The Laurent expansion of the integrand is implemented through polynomial division. The extension of the integrand-reduction...
Source: http://arxiv.org/abs/1203.0291v3
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by Andrei Khrennikov; Elemer E. Rosinger
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Motivated by the novel applications of the mathematical formalism of quantum theory and its generalizations in cognitive science, psychology, social and political sciences, and economics, we extend the notion of the tensor product and entanglement. We also study the relation between conventional entanglement of complex qubits and our generalized entanglement. Our construction can also be used to describe entanglement in the framework of non-Archimedean physics. It is also possible to construct...
Source: http://arxiv.org/abs/1203.0412v1
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Finite element exterior calculus (FEEC) has been developed over the past decade as a framework for constructing and analyzing stable and accurate numerical methods for partial differential equations by employing differential complexes. The recent work of Arnold, Falk and Winther \cite{ArFaWi2010} includes a well-developed theory of finite element methods for Hodge Laplace problems, including a priori error estimates. In this work we focus on developing a posteriori error estimates in which the...
Source: http://arxiv.org/abs/1203.0803v3
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by Jana Jurečková; Jan Kalina
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Although unbiasedness is a basic property of a good test, many tests on vector parameters or scalar parameters against two-sided alternatives are not finite-sample unbiased. This was already noticed by Sugiura [Ann. Inst. Statist. Math. 17 (1965) 261--263]; he found an alternative against which the Wilcoxon test is not unbiased. The problem is even more serious in multivariate models. When testing the hypothesis against an alternative which fits well with the experiment, it should be verified...
Source: http://arxiv.org/abs/1203.0450v1
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by Aaron D. Lauda; Heather M. Russell
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We identify the ring of odd symmetric functions introduced by Ellis and Khovanov as the space of skew polynomials fixed by a natural action of the Hecke algebra at q=-1. This allows us to define graded modules over the Hecke algebra at q=-1 that are `odd' analogs of the cohomology of type A Springer varieties. The graded module associated to the full flag variety corresponds to the quotient of the skew polynomial ring by the left ideal of nonconstant odd symmetric functions. The top degree...
Source: http://arxiv.org/abs/1203.0797v1
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We consider the recurrence and transience problem for a time-homogeneous Markov chain on the real line with transition kernel $p(x,dy)=f_x(y-x)dy$, where the density functions $f_x(y)$, for large $|y|$, have a power-law decay with exponent $\alpha(x)+1$, where $\alpha(x)\in(0,2)$. In this paper, under a uniformity condition on the density functions $f_x(y)$ and some mild technical conditions, we prove that when $\liminf_{|x|\longrightarrow\infty}\alpha(x)>1$, the chain is recurrent, while...
Source: http://arxiv.org/abs/1203.0447v1
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by Jeffrey G. Rau; Hae-Young Kee
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We propose a candidate for the hidden order in URu2Si2: a rank-5 E type spin density wave between Uranium 5f crystal field doublets breaking time reversal and lattice tetragonal symmetry in a manner consistent with recent torque measurements [R. Okazaki et al, Science 331, 439 (2011)]. We argue that coupling of this order parameter to magnetic probes can be hidden by crystal field effects, while still having significant effects on transport, thermodynamics and magnetic susceptibilities. In a...
Source: http://arxiv.org/abs/1203.1047v2
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by Leonardo Motta; Robert R. Caldwell
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We show that a conformal-invariance violating coupling of the inflaton to electromagnetism produces a cross correlation between curvature fluctuations and a spectrum of primordial magnetic fields. According to this model, in the case of power-law inflation, a primordial magnetic field is generated with a nearly flat power spectrum and rms amplitude ranging from nG to pG. We study the cross correlation, a three-point function of the curvature perturbation and two powers of the magnetic field, in...
Source: http://arxiv.org/abs/1203.1033v1
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by Giacomo Ceccarelli; Christian Torrero
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In the framework of the trap-size scaling theory, we study the scaling properties of the Bose-Hubbard model in two dimensions in the presence of a trapping potential at finite temperature. In particular, we provide results for the particle density and the density-density correlator at the Mott transitions and within the superfluid phase. For the former quantity, numerical outcomes are also extensively compared to Local Density Approximation predictions.
Source: http://arxiv.org/abs/1203.2030v3
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by N. Derzsy; Z. Neda; M. A. Santos
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We analyze the income distribution of employees for 9 consecutive years (2001-2009) using a complete social security database for an economically important district of Romania. The database contains detailed information on more than half million taxpayers, including their monthly salaries from all employers where they worked. Besides studying the characteristic distribution functions in the high and low/medium income limits, the database allows us a detailed dynamical study by following the...
Source: http://arxiv.org/abs/1203.1880v1
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A Bayesian nonparametric approach to the study of species diversity based on choosing a random discrete distribution as a prior model for the unknown relative abundances of species has been recently introduced in Lijoi et al. (2007, 2008). Explicit posterior predictive estimation of {\it species richness} has been obtained under priors belonging to the $\alpha$-Gibbs class (Gnedin & Pitman, 2006). Here we focus on posterior estimation of {\it species evenness} which accounts for diversity...
Source: http://arxiv.org/abs/1203.1666v1
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by I. Marti-Vidal; M. A. Perez-Torres; A. P. Lobanov
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We review the effects of source size in interferometric observations and focus on the cases of very compact sources. If a source is extremely compact and/or weak (so it is not possible to detect signature of source structure in the visibilities) we describe a test of hypothesis that can be used to set a strong upper limit to the size of the source. We also estimate the minimum possible size of a source whose structure can still be detected by an interferometer (i.e., the maximum theoretical...
Source: http://arxiv.org/abs/1203.2071v1
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We study finite-frequency quantum noise and photon-assisted electron transport through a wide and ballistic graphene sheet sandwiched between two metallic leads. The elementary excitations allow as to examine the differences between effects related to Fabry-P\'erot like interferences and signatures caused by correlations of coherently scattered particles in electron- and hole-like parts of the Dirac spectrum. We identify different features in the current-current auto- and cross-correlation...
Source: http://arxiv.org/abs/1203.2010v1
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by D. Meloni; S. Morisi; E. Peinado
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In the light of the recent Daya Bay result the reactor angle is about 9 degrees, we reconsider the model presented in arXiv:1005.3482 showing that, when all neutrino oscillation parameters are taken at their best fit values of Schwetz et al and the reactor angle to be the central value of Daya Bay, the predicted value of the CP phase is approximately 45 degrees.
Source: http://arxiv.org/abs/1203.2535v1
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[abridged] We report a series of simulations of the formation of a star cluster similar to the Orion Nebula Cluster (ONC), including both radiative transfer and protostellar outflows, and starting from both smooth and self-consistently turbulent initial conditions. Each simulation forms >150 stars and brown dwarfs, yielding a stellar mass distribution from < 0.1 to > 10 Msun. We show that a simulation that begins with self-consistently turbulence embedded in a larger turbulent volume,...
Source: http://arxiv.org/abs/1203.2620v2
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by R. Giostri; M. Vargas dos Santos; I. Waga; R. R. R. Reis; M. O. Calvão; B. L. Lago
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We use type Ia supernovae (SN Ia) data in combination with recent baryonic acoustic oscillations (BAO) and cosmic microwave background (CMB) observations to constrain a kink-like parametrization of the deceleration parameter ($q$). This $q$-parametrization can be written in terms of the initial ($q_i$) and present ($q_0$) values of the deceleration parameter, the redshift of the cosmic transition from deceleration to acceleration ($z_t$) and the redshift width of such transition ($\tau$). By...
Source: http://arxiv.org/abs/1203.3213v1
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by L. Feng; B. Inhester; Y. Wei; W. Q. Gan; T. L. Zhang; M. Y. Wang
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The propagation properties of coronal mass ejections (CMEs) are crucial to predict its geomagnetic effect. A newly developed three dimensional (3D) mask fitting reconstruction method using coronagraph images from three viewpoints has been described and applied to the CME ejected on August 7, 2010. The CME's 3D localisation, real shape and morphological evolution are presented. Due to its interaction with the ambient solar wind, the morphology of this CME changed significantly in the early phase...
Source: http://arxiv.org/abs/1203.3261v1
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In a recent paper, Gabriel Navarro and Pham Huu Tiep show that the so-called Alperin Weight Conjecture can be verified via the Classification of the Finite Simple Groups, provided any simple group fulfills a very precise list of conditions. Our purpose here is to show that the equivariant refinement of the Alperin's Conjecture for blocks formulated by Geoffrey Robinson in the eighties can be reduced to checking the same statement on any central k*-extension of any finite almost-simple group, or...
Source: http://arxiv.org/abs/1203.3851v3
A hyperbolic type integro-differential equation with two weakly singular kernels is considered together with mixed homogeneous Dirichlet and non-homogeneous Neumann boundary conditions. Existence and uniqueness of the solution is proved by means of Galerkin's method. Regularity estimates are proved and the limitations of the regularity are discussed. The approach presented here is also used to prove regularity of any order for models with smooth kernels, that arise in the theory of linear...
Source: http://arxiv.org/abs/1203.4001v1
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by Vernon Barger; Muneyuki Ishida; Wai-Yee Keung
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By using the LHC and Tevatron measurements of the cross sections to various decay channels relative to the standard model Higgs boson, the total width of the putative 125 GeV Higgs boson is determined as 6.1 +7.7-2.9 MeV. We describe a way to estimate the branching fraction for Higgs decay to dark matter. We also discuss a No-Go theorem for the gammagamma signal of the Higgs boson at the LHC.
Source: http://arxiv.org/abs/1203.3456v3
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by Oriane Aubert; Michael Le Bars; Patrice Le Gal; Philip S. Marcus
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We validate a new law for the aspect ratio $\alpha = H/L$ of vortices in a rotating, stratified flow, where $H$ and $L$ are the vertical half-height and horizontal length scale of the vortices. The aspect ratio depends not only on the Coriolis parameter f and buoyancy (or Brunt-Vaisala) frequency $\bar{N}$ of the background flow, but also on the buoyancy frequency $N_c$ within the vortex and on the Rossby number $Ro$ of the vortex such that $\alpha = f \sqrt{[Ro (1 + Ro)/(N_c^2- \bar{N}^2)]}$....
Source: http://arxiv.org/abs/1203.1562v1
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by S. Sundar
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Let $A \in M_{n}(\mathbb{R})$ be an invertible matrix. Consider the semi-direct product $\mathbb{R}^{n} \rtimes \mathbb{Z}$ where $\mathbb{Z}$ acts on $\mathbb{R}^{n}$ by matrix multiplication. Consider a strongly continuous action $(\alpha,\tau)$ of $\mathbb{R}^{n} \rtimes \mathbb{Z}$ on a $C^{*}$-algebra $B$ where $\alpha$ is a strongly continuous action of $\mathbb{R}^{n}$ and $\tau$ is an automorphism. The map $\tau$ induces a map $\widetilde{\tau}$ on $B \rtimes_{\alpha} \mathbb{R}^{n}$....
Source: http://arxiv.org/abs/1203.0383v1
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by Guillermo F. Hagele; Veronica Firpo; Guillermo Bosch; Angeles I. Diaz; Nidia Morrell
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We present a detailed study of the physical properties of the nebular material in four star-forming knots of the blue compact dwarf galaxy Haro 15. Using long-slit and echelle spectroscopy obtained at Las Campanas Observatory, we study the physical conditions (electron density and temperatures), ionic and total chemical abundances of several atoms, reddening and ionization structure, for the global flux and for the different kinematical components. The latter was derived by comparing the oxygen...
Source: http://arxiv.org/abs/1203.0531v1
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by G. Baumann; K. Galsgaard; Å. Nordlund
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Numerical MHD simulations of 3D reconnection events in the solar corona have improved enormously over the last few years, not only in resolution, but also in their complexity, enabling more and more realistic modeling. Various ways to obtain the initial magnetic field, different forms of solar atmospheric models as well as diverse driving speeds and patterns have been employed. This study considers differences between simulations with stratified and non-stratified solar atmospheres, addresses...
Source: http://arxiv.org/abs/1203.1018v2
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by Masazumi Honda; Yutaka Yoshida
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We show a large N reduction on S^3 in a BPS sector for a broad class of theories : N>=2 supersymmetric Chern-Simons theory with any number of adjoint and bi-fundamental chiral multiplets.We show that a localization method can be applied to the reduced model and the path integral can be written by a multi-contour integral. By taking a particular localization configuration, we also show that the large N equivalence between the original theory on S^3 and the reduced model holds for the free...
Source: http://arxiv.org/abs/1203.1016v2
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by T. Wasak; J. Chwedenczuk; P. Zin; M. Trippenbach
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It is demonstrated that measurements of positions of atoms scattered from a quasi-condensate in a Raman process provide information on the temperature of the parent cloud. In particular, the widths of the density and second order correlation functions are sensitive to the phase fluctuations induced by non-zero temperature of the quasi-condensate. It is also shown how these widths evolve during expansion of the cloud of scattered atoms. These results are useful for planning future Raman...
Source: http://arxiv.org/abs/1203.0894v1
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by Diego Muñoz; Volker Springel; Robert Marcus; Mark Vogelsberger; Lars Hernquist
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Numerous formulations of finite volume schemes for the Euler and Navier-Stokes equations exist, but in the majority of cases they have been developed for structured and stationary meshes. In many applications, more flexible mesh geometries that can dynamically adjust to the problem at hand and move with the flow in a (quasi) Lagrangian fashion would, however, be highly desirable, as this can allow a significant reduction of advection errors and an accurate realization of curved and moving...
Source: http://arxiv.org/abs/1203.1037v1
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by A. Bazavov; Tanmoy Bhattacharya; C. E. DeTar; H. -T. Ding; Steven Gottlieb; Rajan Gupta; P. Hegde; Urs Heller; F. Karsch; E. Laermann; L. Levkova; Swagato Mukherjee; P. Petreczky; Christian Schmidt; R. A. Soltz; W. Soeldner; R. Sugar; Pavlos M. Vranas
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We calculate the quadratic fluctuations of net baryon number, electric charge and strangeness as well as correlations among these conserved charges in (2+1)-flavor lattice QCD at zero chemical potential. Results are obtained using calculations with tree level improved gauge and the highly improved staggered quark (HISQ) actions with almost physical light and strange quark masses at three different values of the lattice cut-off. Our choice of parameters corresponds to a value of 160 MeV for the...
Source: http://arxiv.org/abs/1203.0784v2