July 2013 arXiv papers — page 5

Utkan Güngördü, Yidun Wan, Mikio Nakahara

We implement a non-adiabatic universal set of holonomic quantum gates based on abelian holonomies using dynamical invariants, by Lie-algebraic methods. Unlike previous implementations, presented scheme does not rely on secondary methods such as double-loop or spin-echo and avoids associated experimental difficulties. It turns out that such gates exist purely

Vicente Muñoz

We put in a general framework the situations in which a Riemannian manifold admits a family of compatible complex structures, including hyperkahler metrics and the Spin-rotations of arxiv:1302.2846. We determine the (polystable) holomorphic bundles which are rotable, i.e., they remain holomorphic when we change a complex structure by a different one in the f

Marcin Badziak, Marek Olechowski, Stefan Pokorski

It is shown that substantially enhanced Higgs to diphoton rate induced by light staus with large left-right mixing in MSSM requires at the GUT scale non-universal gaugino masses with bino and/or wino lighter than gluino. The possibility of such enhancement is investigated in MSSM models with arbitrary gaugino masses at the GUT scale with additional restricti

Andrea Cattaneo

In this paper we want to study the non-Kodaira fibres in a smooth equidimensional elliptic threefold. If the morphism to the Weierstrass model of the fibration is crepant, then we can locate the non-Kodaira fibres and give a description of their structure. In particular, they lie over the singular points of the (reduced) discriminant of the fibration and are

Dipankar Chakrabarti, Chandan Mondal

Using the light front wave functions for the nucleons in a quark model in AdS/QCD, we calculate the nucleon electromagnetic form factors. The flavor decompositions of the nucleon form factors are calculated from the GPDs in this model. We show that the nucleon form factors and their flavor decompositions calculated in AdS/QCD are in agreement with experiment

Francesco Mazza, Bernd Braunecker, Patrik Recher, Alfredo Levy Yeyati

We demonstrate that due to their spin-orbit interaction carbon nanotube cross-junctions have attractive spin projective properties for transport. First, we show that the junction can be used as a versatile spin filter as a function of a backgate and a static external magnetic field. Switching between opposite spin filter directions can be achieved by small c

Ian Melbourne, Dalia Terhesiu

We develop operator renewal theory for flows and apply this to infinite ergodic theory. In particular we obtain results on mixing for a large class of infinite measure semiflows. Examples of systems covered by our results include suspensions over parabolic rational maps of the complex plane, and nonuniformly expanding semiflows with indifferent periodic orbi

Manik Banik, Some Sankar Bhattacharya, Sujit K Choudhary, Amit Mukherjee

The ontological model framework for an operational theory has generated much interest in recent years. The debate concerning reality of quantum states has been made more precise in this framework. With the introduction of generalized notion of contextuality in this framework, it has been shown that completely mixed state of a qubit is \emph{preparation conte

Michael Cuntz

The entries of frieze patterns may be interpreted as coordinates of roots of a finite Weyl groupoid of rank two. We prove the existence of maximal elements in their root posets and classify those frieze patterns which can be used to build an affine simplicial arrangement.

Khodabakhsh Hessami Pilehrood, Tatiana Hessami Pilehrood, Jianqiang Zhao

In recent years, there has been intensive research on the ${\mathbb Q}$-linear relations between multiple zeta (star) values. In this paper, we prove many families of identities involving the $q$-analog of these values, from which we can always recover the corresponding classical identities by taking $q\to 1$. The main result of the paper is the duality rela

Akimasa Kataoka, Hidekazu Tanaka, Satoshi Okuzumi, Koji Wada

Context: In planetesimal formation theory, several barriers have been proposed, which are bouncing, fragmentation, and radial drift problems. To understand the structure evolution of dust aggregates is a key in the planetesimal formation. Dust grains become fluffy by coagulation in protoplanetary disks. However, once they become fluffy, they are not sufficie

Marek Demiański, Andrey Doroshkevich

We apply the well known semi analytical model of formation of DM halos to discuss the process of formation and evolution of the relaxed objects dominated by the DM component (such as the first and dSph galaxies and clusters of galaxies). On the one hand this approach allows us to obtain a simple description of evolution of the first galaxies. On the other ha

Hamzeh Alavirad, Joel M. Weller

We consider the effect of a logarithmic f(R) theory, motivated by the form of the one-loop effective action arising from gluons in curved spacetime, on the structure of relativistic stars. In addition to analysing the consistency constraints on the potential of the scalar degree of freedom, we discuss the possibility of observational features arising from a

Danny Dolev, Christoph Lenzen

The majority of the literature on consensus assumes that protocols are jointly started at all nodes of the distributed system. We show how to remove this problematic assumption in semi-synchronous systems, where messages delays and relative drifts of local clocks may vary arbitrarily within known bounds. Our framework is self-stabilizing and efficient both i

Jorge Peixinho, Hugues Besnard

The results of a combined experimental and numerical study of the flow in slowly diverging pipes are presented. Interestingly, an axisymmetric conical recirculation cell has been observed. The conditions for its existence and the length of the cell are simulated for a range of diverging angles and expansion ratios. There is a critical velocity for the appear

David J Nott, Minh-Ngoc Tran, Anthony Y. C. Kuk, Robert Kohn

The article develops a hybrid Variational Bayes algorithm that combines the mean-field and fixed-form Variational Bayes methods. The new estimation algorithm can be used to approximate any posterior without relying on conjugate priors. We propose a divide and recombine strategy for the analysis of large datasets, which partitions a large dataset into smaller

Meydi Ferrier, Bastien Dassonneville, Sophie Gueron, Helene Bouchiat

A long phase coherent normal (N) wire between superconductors (S) is characterized by a dense phase dependent Andreev spectrum. We investigate the current response of Andreev states of an NS ring to a time dependent Aharonov Bohm flux superimposed to a dc one. The ring is modeled with a tight binding Hamiltonian including a superconducting region with a BCS

Goncalo Tabuada

The Weil restriction functor, introduced in the late fifties, was recently extended by Karpenko to the category of Chow motives with integral coefficients. In this article we introduce the noncommutative (=NC) analogue of the Weil restriction functor, where schemes are replaced by dg algebras, and extend it to Kontsevich's categories of NC Chow motives a

Lorenzo Battarra, George Lavrelashvili, Jean-Luc Lehners

We perform a detailed study of the existence and the properties of O(4)-invariant instanton solutions in Einstein-scalar theory in the presence of flat potential barriers, i.e. barriers where the second derivative of the potential is small at the top of the barrier. We find a whole zoo of solutions: Hawking-Moss, Coleman-De Luccia (CdL), oscillating instanto

Jim Pitman, Wenpin Tang

For a continuous function $f \in \mathcal{C}([0,1])$, define the Vervaat transform $V(f)(t):=f(τ(f)+t \mod1)+f(1)1_{\{t+τ(f) \geq 1\}}-f(τ(f))$, where $τ(f)$ corresponds to the first time at which the minimum of $f$ is attained. Motivated by recent study of quantile transforms for random walks and Brownian motion, we study the Vervaat transform of Brownian m

Xia Shen

Presented here is a simple method for cross-validated genome-wide association studies (cvGWAS). Focusing on phenotype prediction, the method is able to reveal a significant amount of missing heritability by properly selecting a small number of loci with implicit predictive ability. The results provide new insights into the missing heritability problem and th

Cai Meng, Zhihui Li, Jingyu Tang

The injector (Scheme-I) of the C-ADS linac is a 10-mA 10-MeV proton linac working in CW mode. It is mainly comprised of a 3.2-MeV room-temperature 4-vane RFQ and twelve superconducting single-spoke cavities housed in a long cryostat. Error analysis including alignment and field errors, static and dynamic ones for the injector are presented. Based on detailed

Goncalo Tabuada, Michel Van den Bergh

Let k be a base commutative ring, R a commutative ring of coefficients, X a quasi-compact quasi-separated k-scheme, A a sheaf of Azumaya algebras over X of rank r, and Hmo(R) the category of noncommutative motives with R-coefficients. Assume that 1/r belongs to R. Under this assumption, we prove that the noncommutative motives with R-coefficients of X and A

Rami Luisto, Pekka Pankka

We show that for a closed $n$-manifold $N$ admitting a quasiregular mapping from the Euclidean $n$-space the following are equivalent: (1) order of growth of $π_1(N)$ is $n$, (2) $N$ is aspherical, and (3) $π_1(N)$ is virtually $\mathbb{Z}^n$ and torsion free.

Renata Kallosh, Andrei Linde

Recently we identified a new class of (super)conformally invariant theories which allow inflation even if the scalar potential is very steep in terms of the original conformal variables. Observational predictions of a broad class of such theories are nearly model-independent. In this paper we consider generalized versions of these models where the inflaton h

Irene Tamborra, Florian Hanke, Bernhard Mueller, Hans-Thomas Janka

The first full-scale three-dimensional (3D) core-collapse supernova (SN) simulations with sophisticated neutrino transport show pronounced effects of the standing accretion shock instability (SASI) for two high-mass progenitors (20 and 27 M_sun). In a low-mass progenitor (11.2 M_sun), large-scale convection is the dominant nonradial hydrodynamic instability

Selym Villalba-Chávez, Antonino Di Piazza

The propagation of a probe electromagnetic field through a counterpropagating strong plane wave is investigated. The effects of the electromagnetic field-(pseudo)scalar axion field interaction and of the self-interaction of the electromagnetic field mediated by virtual electron-positron pairs in the effective Lagrangian approach are included. First, we show

Leandro F. Aurichi, Angelo Bella

The two main results of this work are the following: if a space $X$ is such that player II has a winning strategy in the game $\gone(Ω_x, Ω_x)$ for every $x \in X$, then $X$ is productively countably tight. On the other hand, if a space is productively countably tight, then $\sone(Ω_x, Ω_x)$ holds for every $x \in X$. With these results, several other result

Zong-Gang Mou, Paul M. Saffin, Anders Tranberg

We refine the implementation of ensemble fermions for the electroweak sector of the Standard Model, introduced previously. We consider the behavior of different observables as the size of the ensemble is increased and show that the dynamics converges for ensemble sizes small enough that simulations of the entire electroweak sector become numerically tractabl

Y. Ota, K. Okazaki, Y. Kotani, T. Shimojima

We have investigated the superconducting(SC)-gap anisotropy for several Ba-doped KFe$_2$As$_2$ samples using laser-based angle-resolved photoemission spectroscopy. We show that the SC-gap anisotropy and node positions drastically change with a small amount of Ba doping. Our results totally exclude a possibility of $d$-wave symmetry and strongly suggest that

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

Bright fireballs or bolides are caused by meteoroids entering the Earth's atmosphere at high speed. On 2013 February 15, a superbolide was observed in the skies near Chelyabinsk, Russia. Such a meteor could be the result of the decay of an asteroid and here we explore this possibility applying a multistep approach. First, we use available data and Monte

Anders Andersson, Borje Nilsson, Thomas Biro

A set of semi-analytical techniques based on Fourier analysis is used to solve wave scattering problems in variously shaped waveguides with varying normal admittance boundary conditions. Key components are newly developed conformal mapping methods, wave splitting, Fourier series expansions in eigen-functions to non-normal operators, the building block method

O. Dubinkin

We construct Virasoro algebra of differential operators for the Jones-Rosso matrix model. These operators generate various relations between Wilson loops. Then we discuss the con- structed operators and corresponding relations in the stability limit. A series of examples is given.

R. Escribano, S. González-Solís, P. Roig

We have studied the $τ^-\to K^-η^{(\prime)}ν_τ$ decays within Chiral Perturbation Theory including resonances as explicit degrees of freedom. We have considered three different form factors according to treatment of final-state interactions. In increasing degree of soundness: Breit-Wigner, exponential resummation and dispersive representation. We find that a

Andrzej Grudka, Karol Horodecki, Michał Horodecki, Waldemar Kłobus

We study a problem of interconvertibility of two supra-quantum resources: one is so called PR-box, which violates CHSH inequality up to maximal algebraic bound, and second is so called random access code (RAC). The latter is a functionality that enables Bob (receiver) to choose one of two bits of Alice. It has been known, that PR-box supplemented with one bi

Satoru Morita, Jin Yoshimura

We study a stochastic matrix model to understand the mechanics of risk-spreading (or bet-hedging) by dispersion. Such model has been mostly dealt numerically except for well-mixed case, so far. Here, we present an analytical result, which shows that optimal dispersion leads to Zipf's law. Moreover, we found that the arithmetic ensemble average of the tot

Giacomo Mauro D'Ariano, Franco Manessi, Paolo Perinotti, Alessandro Tosini

We show that the computational model based on local Fermionic modes in place of qubits does not satisfy local tomography and monogamy of entanglement, and has mixed states with maximal entanglement of formation. These features directly follow from the parity conservation corresponding to the parity superselection rule. We generalize quantum superselection ru

Pedro Costa, Márcio Ferreira, Hubert Hansen, Débora P. Menezes

The location of the critical end point (CEP) in the QCD phase diagram is determined under different scenarios. The effect of strangeness, isospin/charge asymmetry and an external magnetic field is investigated. The discussion is performed within the 2+1 flavor Nambu--Jona-Lasinio model with Polyakov loop. It is shown that isospin asymmetry shifts the CEP to

Daniel Karrasch, George Haller

Ridges of the Finite-Size Lyapunov Exponent (FSLE) field have been used as indicators of hyperbolic Lagrangian Coherent Structures (LCSs). A rigorous mathematical link between the FSLE and LCSs, however, has been missing. Here we prove that an FSLE ridge satisfying certain conditions does signal a nearby ridge of some Finite-Time Lyapunov Exponent (FTLE) fie

Carsten Schneider

Parameterized telescoping (including telescoping and creative telescoping) and refined versions of it play a central role in the research area of symbolic summation. Karr introduced 1981 $ΠΣ$-fields, a general class of difference fields, that enables one to consider this problem for indefinite nested sums and products covering as special cases, e.g., the ($q

Magali Lécureux-Mercier

In this article we derive C^1-a priori estimates on the Riemann invariants of the Euler compressible equations in the case of cylindrical or spherical symmetry. These estimates allow then to construct shock waves with a time of existence proportional to the distance to the origin at the initial time.

Sergey Petoukhov

This article is devoted to applications of projection operators to simulate phenomenological properties of the molecular-genetic code system. Oblique projection operators are under consideration, which are connected with matrix representations of the genetic coding system in forms of the Rademacher and Hadamard matrices. Evidences are shown that sums of such

Arata Komyo

In this paper, we construct compactifications of $SL_2(\mathbb{C})$-character varieties of $n$-punctured projective line and study the boundary divisor of the compactifications. This study is motivated by the conjecture for the configuration of the boundary divisor, due to C. Simpson. We verify the conjecture for a few examples.

Gian F. Giudice

I review the status of naturalness of the weak scale after the results from the LHC operating at an energy of 8 TeV. Talk delivered at the 2013 Europhysics Conference on High Energy Physics (EPS), Stockholm, Sweden, 18-24 July 2013.

Michael Tomka, Omar El Araby, Mikhail Pletyukhov, Vladimir Gritsev

We study the spectrum of the generalized Rabi model in which co- and counter-rotating terms have different coupling strengths. It is also equivalent to the model of a two-dimensional electron gas in a magnetic field with Rashba and Dresselhaus spin-orbit couplings. Like in case of the Rabi model, the spectrum of the generalized Rabi model consists of the reg

Kamil Szpojankowski

In the paper we study characterizations of probability measures in free probability. By constancy of regressions for random variable $\V(\I-\U)\V$ given by $\V\U\V$, where $\U$ and $\V$ are free, we characterize free Poisson and free binomial distributions. Our paper is analog in free probability of results known in classical probability \cite{BobWes2002Dual

Johannes S. Hofmann, Raquel Queiroz, Andreas P. Schnyder

Topological superconductors, such as noncentrosymmetric superconductors with strong spin-orbit coupling, exhibit protected zero-energy surface states, which possess an intricate helical spin structure. We show that this nontrival spin character of the surface states can be tested experimentally from the absence of certain backscattering processes in Fourier-

Kaixi Feng, Taotao Qiu, Yun-Song Piao

We show a curvaton model, in which the curvaton has a nonminimal derivative coupling to gravity. Thanks to such a coupling, we find that the scale-invariance of the perturbations can be achieved for arbitrary values of the equation-of-state of background, provided that it is nearly a constant. We also discussed about tensor perturbations, the local non-Gauss

Martiros Khurshudyan, Amalya Khurshudyan

Motivated by recent developments in Cosmology we would like to consider an extension of the Ghost DE which we will call as varying Ghost DE. Ghost DE like other models was introduced recently as a possible way to explain accelerated expansion of the Universe. For the phenomenological origin of the varying Ghost dark energy in our Universe we can suggest an e

Grzegorz Wilk, Zbigniew Włodarczyk

Selected examples of possible origins of power-law distributions are presented.

Aurélien Decelle, Florent Krzakala

A Monte-Carlo algorithm for discrete statistical models that combines the full power of the Belief Propagation algorithm with the advantages of a detailed-balanced heat bath approach is presented. A sub-tree inside the factor graph is first extracted randomly; Belief Propagation is then used as a perfect sampler to generate a configuration on the tree given

Kozo Okazaki, Yoshiaki Ito, Yuichi Ota, Yoshinori Kotani

Conventional superconductivity follows Bardeen-Cooper-Schrieffer(BCS) theory of electrons-pairing in momentum-space, while superfluidity is the Bose-Einstein condensation(BEC) of atoms paired in real-space. These properties of solid metals and ultra-cold gases, respectively, are connected by the BCS-BEC crossover. Here we investigate the band dispersions in

Kenny Wong

The AdS/CFT correspondence predicts that background non-abelian magnetic fields induce instabilities in strongly-coupled systems with non-abelian global symmetries. These instabilities lead to the formation of vortex lattices in which the non-abelian currents "antiscreen" the applied magnetic field. From the bulk perspective, this behaviour can be tr

Sang Yeob Jung, Seung Min Yu, Seong-Lyun Kim

We study bidding and pricing competition between two spiteful mobile network operators (MNOs) with considering their existing spectrum holdings. Given asymmetric-valued spectrum blocks are auctioned off to them via a first-price sealed-bid auction, we investigate the interactions between two spiteful MNOs and users as a three-stage dynamic game and character

Mohab Safey El Din, Eric Schost

A roadmap for a semi-algebraic set $S$ is a curve which has a non-empty and connected intersection with all connected components of $S$. Hence, this kind of object, introduced by Canny, can be used to answer connectivity queries (with applications, for instance, to motion planning) but has also become of central importance in effective real algebraic geometr

Vishnu M. Bannur

Landau's formalism of statistical mechanics \cite{la.1} is applied to the quasiparticle model of quark gluon plasma. It is a general formalism and consistent with our earlier studies \cite{ba.1} based on Pathria's formalism \cite{pa.1}. Both the formalism are consistent with thermodynamics and statistical mechanics. Under certain conditions, which ar

Giacomo Artoni, Tongyan Lin, Bjoern Penning, Gabriella Sciolla

We present projections for future collider searches for dark matter produced in association with bottom or top quarks. Such production channels give rise to final states with missing transverse energy and one or more b-jets. Limits are given assuming an effective scalar operator coupling dark matter to quarks, where the dedicated analysis discussed here impr

William Fithian, Stefan Wager

We propose a semiparametric method for fitting the tail of a heavy-tailed population given a relatively small sample from that population and a larger sample from a related background population. We model the tail of the small sample as an exponential tilt of the better-observed large-sample tail, using a robust sufficient statistic motivated by extreme valu

S. V. Molodtsov, G. M. Zinovjev

Studying a model of four-quark interaction with large correlation length we find out both the features peculiar an unitary fermi gas and the specific anomalous properties of the fermi systems with a fermion condensate. It is argued that a possibility of phase transition originated by interface between the Fermi sphere and fermion condensate appears in such q

Eugene Levin, Irina Potashnikova

In this paper we developed approach based on the BFKL evolution in $\ln\Lb Q^2\Rb$. We show that the simplest diffusion approximation with running QCD coupling is able to describe the HERA experimental data on the deep inelastic structure function with good $χ^2/d.o.f. \approx 1.3$. From our description of the experimental data we learned several lessons; (i

Jesper Jansson, Chuanqi Shen, Wing-Kin Sung

This paper presents two new deterministic algorithms for constructing consensus trees. Given an input of k phylogenetic trees with identical leaf label sets and n leaves each, the first algorithm constructs the majority rule (+) consensus tree in O(kn) time, which is optimal since the input size is Omega(kn), and the second one constructs the frequency diffe

Alexander P. Ellis, Aaron D. Lauda

We define a 2-category that categorifies the covering Kac-Moody algebra for sl(2) introduced by Clark and Wang. This categorification forms the structure of a super-2-category as formulated by Kang, Kashiwara, and Oh. The super-2-category structure introduces a (Z x Z_2)-grading giving its Grothendieck group the structure of a free module over the group alge

C. Pallis

We show how we can implement chaotic inflation in the context of supergravity by conveniently selecting the functional form of a strong enough non-minimal coupling between the inflaton and the Ricci scalar curvature. The procedure can be applied when a gauge singlet or non-singlet inflaton is coupled to another singlet superfield within linear-quadratic, tri

Stefano Profumo, Farinaldo S. Queiroz

We investigate a so-called 331 extension of the Standard Model gauge sector which accommodates neutrino masses and where the lightest of the new neutral fermions in the theory is a viable particle dark matter candidate. In this model, processes mediated by the additional $Z^{\prime}$ gauge boson set both the dark matter relic abundance and the scattering cro

Sergii Domanskyi, Vladimir Privman

We propose the concept of autonomous self-damaging in "smart" composite materials, controlled by activation of added nanosize "damaging" capsules. Percolation-type modeling approach earlier applied to the related concept of self-healing materials, is used to investigate the behavior of the initial material's fatigue. We aim at achieving a

Daniel B. Grunberg, Hao Pan, Zhi-Wei Sun

We prove a curious identity for the Bernoulli numbers.

Aaron Miller, Dezhe Z. Jin

Synfire chains are thought to underlie precisely-timed sequences of spikes observed in various brain regions and across species. How they are formed is not understood. Here we analyze self-organization of synfire chains through the spike-timing dependent plasticity (STDP) of the synapses, axon remodeling, and potentiation decay of synaptic weights in network

Lei Wang, Jin Min Yang, Jingya Zhu

We examine the status of dark matter (heavy photon) in the littlest Higgs model with T-parity (LHT) in light of the new results from the LHC Higgs search, the Planck dark matter relic density and the XENON100 limit on the dark matter scattering off the nucleon. We obtain the following observations: (i) For the LHC Higgs data, the LHT can well be consistent w

Maĺgorzata Stawiska

This paper, based in part on joint work with Stanisław Domoradzki, concerns Lucjan Emil Böttcher (1872-1937)-- a little-known Polish mathematician active in Lwów. I outline Böttcher's scholarly path, focusing on his studies in Leipzig with Sophus Lie, his later academic career in Lwów and the hindrances he faced in its advancement. I also describe very b

Manan Mehta, Venkat Chandrasekhar

Non-contact scanning probe microscopy (SPM) has developed into a powerful technique to image many different properties of samples. The conventional method involves monitoring the amplitude, phase or frequency of a cantilever oscillating at or near its resonant frequency as it is scanned across the surface of a sample. For high Q factor cantilevers, monitorin

Jonathan Korman, Robert J. McCann, Christian Seis

Optimal transportation with capacity constraints, a variant of the well-known optimal transportation problem, is concerned with transporting one probability density $f \in L^1(\mathbb{R}^m)$ onto another one $g \in L^1(\mathbb{R}^n)$ so as to optimize a cost function $c \in L^1(\mathbb{R}^{m+n})$ while respecting the capacity constraints $0\le h \le \bar h\i

Adi Armoni, Maurizio Piai, Ali Teimouri

We study the correlators of two circular Wilson loops of different radii at strong coupling. In our setup one Wilson loop is located inside the other. We use holography to calculate the connected two-point function. Both an AdS background and a confining background are considered. As the computation for the confining case cannot be carried out analytically w

Leandro P. R. Pimentel

In this paper we prove a duality relation between coalescence times and exit points in last-passage percolation models with exponential weights. As a consequence, we get lower bounds for coalescence times with scaling exponent 3/2, and we relate its distribution with variational problems involving the Brownian motion process and the Airy process.

Lucius G Meredith, Mike Stay, Sophia Drossopoulou

Drossopoulou and Noble argue persuasively for the need for a means to express policy in object-capability-based systems. We investigate a practical means to realize their aim via the Curry-Howard isomorphism. Specifically, we investigate representing policy as types in a behavioral type system for the RHO-calculus, a reflective higher-order variant of the pi

June Huh

We construct a quartic threefold with L-rational singularities which has torsion in its middle homology group. This answers a question of Brown and Schnetz for all fields of characteristic zero.

Hongwei Wang, F. Richard Yu, Li Zhu, Tao Tang

Leaky waveguide has been adopted in communication based train control (CBTC) systems, as it can significantly enhance railway network efficiency, safety and capacity. Since CBTC systems have high requirements for the train ground communications, modeling the leaky waveguide channels is very important to design the wireless networks and evaluate the performan

Samuel Coogan, Murat Arcak

It is well know that for globally contractive autonomous systems, there exists a unique equilibrium and the distance to the equilibrium evaluated along any trajectory decreases exponentially with time. We show that, additionally, the magnitude of the velocity evaluated along any trajectory decreases exponentially, thus giving an alternative choice of Lyapuno

Javier Garcia, Francisco M Fernández

We discuss Rayleigh-Ritz variational calculations with nonorthogonal basis sets that exhibit the correct asymptotic behaviour. We construct the suitable basis sets for general one-dimensional models and illustrate the application of the approach on two double-well oscillators proposed recently by other authors. The rate of convergence of the variational meth

M. A. Guerrero, J. A. Toalá, J. J. Medina, V. Luridiana

The propagation of a shock wave into a medium is expected to heat the material beyond the shock, producing noticeable effects in intensity line ratios such as [O III]/Halpha. To investigate the occurrence of shocks in planetary nebulae (PNe), we have used all narrowband [O III] and Halpha images of PNe available in the HST archive to build their [O III]/Halp

D. Momeni, R. Myrzakulov, M. Raza

In this paper, we analytically compute the basic parameters of the p-wave holographic superconductors with Weyl geometrical corrections using the matching method. The explicit correspondence between the critical temperature $T_c$ and the dual charge density $ρ$ has been calculated as $T_c\proptoρ^{{1}{3}}$ and the dependence of the vacuum expectation value f

Nana Yaw Asabere, Nana Kwame Gyamfi

The performance of employees in an organization is a very important issue for effective delivery and output. Various performance management systems with the aid of Information and Communication Technology (ICT) are currently being used by companies. Such systems are most of the time connected and accessible through to the internet / www. Through review of re

Firas Al Rekabi, Asim El Sheikh

In simulation, Median Polish Kriging is a technique used to predict unobserved data points in two-dimensional space. The linear behavior of the traditional Median Polish Kriging in the estimation of the mean function in a high grid makes the interpolation of O(1) which has a low order in the prediction and that leads to a high prediction error. Therefore, an

David James

We have created a digital spectral library, using low resolution optical spectra, of photometric and spectral standard stars. The data were acquired using the Cassegrain Spectrograph installed on the 1.9m Radcliffe telescope at the South African Astronomical Observatory. The library consists of optical wavelength (~ 3500-7500AA) spectra for main sequence and

Rastko Aničić, Zoran L. Mišković

We investigate the conductivity of doped graphene in the semiclassical Boltzmann limit, as well as the conductivity minimum within the self-consistent transport theory. Using the hard-disk model for a two-dimensional distribution of impurities gives rise to both strong increase in the slope of conductivity at low charge carrier densities in graphene and a st

Yasunori Maekawa, Hideyuki Miura

Let $Ω$ be a domain with noncompact boundary. It is known that the Helmholtz decomposition is not always valid in $L^p(Ω)$ except for the energy space $L^2 (Ω)$. In this paper we consider a typical unbounded domain whose boundary is given as a Lipschitz graph, and show that the Helmholtz decomposition holds in certain anisotropic spaces which include some in

Niels Ubbelohde, Christian Fricke, Frank Hohls, Rolf J. Haug

The spin-dependent dynamical blockade was investigated in a lateral quantum dot in a magnetic field. Spin-polarized edge channels in the two-dimensional leads and the spatial distribution of Landau orbitals in the dot modulate the tunnel coupling of the quantum dot level spectrum. In a measurement of the electron shot noise we observe a pattern of super-Pois

D. Kölbl, D. M. Zumbühl

We present transport measurements on quantum dots of sizes 45, 60 and 80 nm etched with an Ar/O2-plasma into a single graphene sheet, allowing a size comparison avoiding effects from different graphene flakes. The transport gaps and addition energies increase with decreasing dot size, as expected, and display a strong correlation, suggesting the same physica

Darcy Best, Hadi Kharaghani, Hugh Ramp

Inspired by the many applications of mutually unbiased Hadamard matrices, we study mutually unbiased weighing matrices. These matrices are studied for small orders and weights in both the real and complex setting. Our results make use of and examine the sharpness of a very important existing upper bound for the number of mutually unbiased weighing matrices.

S. Quaglioni, C. Romero-Redondo, P. Navrátil

We introduce a fully antisymmetrized treatment of three-cluster dynamics within the ab initio framework of the no-core shell model/resonating-group method (NCSM/RGM). Energy-independent non-local interactions among the three nuclear fragments are obtained from realistic nucleon-nucleon interactions and consistent ab initio many-body wave functions of the clu

J. G. Coelho, M. Malheiro

SGRs/AXPs are considered a subclass of pulsars powered by magnetic energy and not by rotation, as normal radio pulsars. They are understood as strongly magnetized neutron star, with large periods of rotation $P\sim(2-12)$ s, and large spin-down, with typical $\dot{P}\sim(10^{-13}-10^{-10})$ s/s in contrast to $\dot{P}\sim10^{-15}$ s for ordinary pulsars. The

Mark J. Burke, Ralph P. Kraft, Roberto Soria, Thomas J. Maccarone

We report new detections of the two transient ultraluminous X-ray sources (ULXs) in NGC 5128 from an ongoing series of Chandra observations. Both sources have previously been observed Lx (2-3)E39 erg/s, at the lower end of the ULX luminosity range. The new observations allow us to study these sources in the luminosity regime frequented by the Galactic black

Neophytos Neophytou, Hans Kosina

Large efforts in improving thermoelectric energy conversion are devoted to energy filtering by nanometer size potential barriers. In this work we perform an analysis and optimization of such barriers for improved energy filtering. We merge semiclassical with quantum mechanical simulations to capture tunneling and reflections due to the barrier, and analyze t

J. P. Byrne, D. M. Long, P. T. Gallagher, D. S. Bloomfield

The study of solar eruptive events and associated phenomena is of great importance in the context of solar and heliophysics. Coronal mass ejections (CMEs) and coronal waves are energetic manifestations of the restructuring of the solar magnetic field and mass motion of the plasma. Characterising this motion is vital for deriving the dynamics of these events

Gerald Hechenblaikner, Reinhold Flatscher

The LISA Pathfinder mission to space employs an optical metrology system (OMS) at its core to measure the distance and attitude between two freely floating test-masses to picometer and nanorad accuracy, respectively, within the measurement band of [1 mHz, 30 mHz]. The OMS is based upon an ultra-stable optical bench with 4 heterodyne interferometers from whic

Neophytos Neophytou, Hans Kosina

We analyze the effect of low dimensionality on the electrical conductivity (σ) and Seebeck coefficient (S) in ultra-narrow Si nanowires (NWs) by employing atomistic considerations for the electronic structures and linearized Boltzmann transport theory. We show that changes in the geometrical features of the NWs such as diameter and orientation, mostly affect

S. W. Allen, A. B. Mantz, R. G. Morris, D. E. Applegate

In addition to cosmological tests based on the mass function and clustering of galaxy clusters, which probe the growth of cosmic structure, nature offers two independent ways of using clusters to measure cosmic distances. The first uses measurements of the X-ray emitting gas mass fraction, which is an approximately standard quantity, independent of mass and

Yasunori Maekawa, Hideyuki Miura

We consider second order uniformly elliptic operators of divergence form in $\R^{d+1}$ whose coefficients are independent of one variable. Under the Lipschitz condition on the coefficients we characterize the domain of the Poisson operators and the Dirichlet-Neumann maps in the Sobolev space $H^s(\R^d)$ for each $s\in [0,1]$. Moreover, we also show a factori

Ahmed Almheiri, James Sully

We investigate the possibility of firewalls in the Einstein-dilaton gravity model of CGHS. We use the results of the numerical simulation carried out by Ashtekar et al. to demonstrate that firewalls are absent and the horizon is drama free. We show that the lack of a firewall is consistent because the model does not satisfy one of the postulates of black hol

Fernando Haas

Recently there has been great interest around quantum relativistic models for plasmas. In particular striking advances have been obtained by means of the Klein-Gordon-Maxwell system, which provides a first order approach to the relativistic regimes of quantum plasmas. It is a reliable method as long as the plasma spin dynamics is not a fundamental aspect, to

F. Ciaraldi-Schoolmann, I. R. Seitenzahl, F. K. Roepke

A promising model for normal Type Ia supernova (SN Ia) explosions are delayed detonations of Chandrasekhar-mass white dwarfs, in which the burning starts out as a subsonic deflagration and turns at a later phase of the explosion into a supersonic detonation. The mechanism of the underlying deflagration-to-detonation transition (DDT) is unknown in detail, but