May 2010 arXiv papers — page 46
Showing 4,501–4,600 of 5,722 papers
Potential of the next generation VHE instruments to probe the EBL (I): the low- and mid-VHE
astro-ph.COMartin Raue, Daniel Mazin
The diffuse meta-galactic radiation field at ultraviolet to infrared wavelengths - commonly labeled extragalactic background light (EBL) - contains the integrated emission history of the universe. Difficult to access via direct observations indirect constraints on its density can be derived through observations of very-high energy (VHE; E>100 GeV) gamma-rays
Julien Bringer, Hervé Chabanne
Negative databases - negative representations of a set of data - have been introduced in 2004 to protect the data they contain. Today, no solution is known to constitute biometric negative databases. This is surprising as biometric applications are very demanding of such protection for privacy reasons. The main difficulty comes from the fact that biometric c
Paul Fearnhead, Benjamin M. Taylor
Sequential Monte Carlo (SMC) methods are not only a popular tool in the analysis of state space models, but offer an alternative to MCMC in situations where Bayesian inference must proceed via simulation. This paper introduces a new SMC method that uses adaptive MCMC kernels for particle dynamics. The proposed algorithm features an online stochastic optimiza
Inflation in models with Conformally Coupled Scalar fields: An application to the Noncommutative Spectral Action
hep-thMichel Buck, Malcolm Fairbairn, Mairi Sakellariadou
Slow-roll inflation is studied in theories where the inflaton field is conformally coupled to the Ricci scalar. In particular, the case of Higgs field inflation in the context of the noncommutative spectral action is analyzed. It is shown that while the Higgs potential can lead to the slow-roll conditions being satisfied once the running of the self-coupling
Matjaž Konvalinka, Götz Pfeiffer, Claas Röver
The normalizer $N_W(W_J)$ of a standard parabolic subgroup $W_J$ of a finite Coxeter group $W$ splits over the parabolic subgroup with complement $N_J$ consisting of certain minimal length coset representatives of $W_J$ in $W$. In this note we show that (with the exception of a small number of cases arising from a situation in Coxeter groups of type $D_n$) t
Stefano Viaggiu
We build an exact inhomogeneous universe composed of a central flat Friedmann zone up to a small redshift $z_1$, a thick shell made of anisotropic matter, an hyperbolic Friedmann metric up to the scale where dimming galaxies are observed ($z\simeq 1.7$) that can be matched to a hyperbolic Lemaître-Tolman-Bondi spacetime to best fit the WMAP data at early epo
Steven Finch
The joint distribution of two off-diagonal Wishart matrix elements was useful in recent work on geometric probability [Finch 2010]. Not finding such formulas in the literature, we report these here.
R. N. Karasev, F. V. Petrov
In this paper we prove that the nonzero elements of a finite field with odd characteristic can be partitioned into pairs with prescribed difference (maybe, with some alternatives) in each pair. The algebraic and topological approaches to such problems are considered. We also give some generalizations of these results to packing translates in a finite or infi
J. Steinheimer, S. Schramm
We calculate the 2nd and 4th order quark number susceptibilities at zero baryochemical potential, using a PNJL approach and an approach which includes, in a single model, quark and hadronic degrees of freedom. We observe that the susceptibilities are very sensitive to possible quark-quark vector interactions. Compared to lattice data our results suggest that
Joan Camps, Roberto Emparan
We construct several new families of vacuum solutions that describe black holes in uniformly accelerated motion. They generalize the C-metric to the case where the energy density and tension of the strings that pull (or push) on the black holes are independent parameters. These strings create large curvatures near their axis and when they have infinite lengt
Hadrien Bosetti, Harald A. Posch
We carry out extensive computer simulations to study the Lyapunov instability of a two-dimensional hard disk system in a rectangular box with periodic boundary conditions. The system is large enough to allow the formation of Lyapunov modes parallel to the x axis of the box. The Oseledec splitting into covariant subspaces of the tangent space is considered by
Hayato Motohashi, Alexei A. Starobinsky, Jun'ichi Yokoyama
The effect of massive neutrinos on matter power spectrum is discussed in the context of $f(R)$ gravity. It is shown that the anomalous growth of density fluctuations on small scales due to the scalaron force can be compensated by free streaming of neutrinos. As a result, models which predict observable deviation of the equation-of-state parameter $w_\DE$ fro
Importance of Itinerancy and Quantum Fluctuations for the Magnetism in Iron Pnictides
cond-mat.str-elYu-Zhong Zhang, Hunpyo Lee, Ingo Opahle, Harald O. Jeschke
By applying density functional theory, we find strong evidence for an itinerant nature of magnetism in two families of iron pnictides. Furthermore, by employing dynamical mean field theory with continuous time quantum Monte Carlo as an impurity solver, we observe that the antiferromagnetic metal with small magnetic moment naturally arises out of coupling bet
Xin Li, Zhe Chang
Verlinde has suggested that the gravity has an entropic origin, and a gravitational system could be regarded as a thermodynamical system. It is well-known that the equipartition law of energy is invalid at very low temperature. Therefore, entropic force should be modified while the temperature of the holographic screen is very low. It is shown that the modif
M. Z. Sarikaya, H. Ogunmez, M. K. Yildiz
In this paper, we establish new general inequality for convex functions. Then we apply this inequality to obtain the midpoint, trapezoid and averaged midpoint-trapezoid integral inequality. Also, some applications for special means of real numbers are provided.
Hisashi Kasuya
We represent the coordinate ring of algebraic hulls (which are generalizations of the Malcev completions of nilpotent groups for solvable groups) of solvmanifolds $G/Γ$ by using Miller's exponential iterated integrals (which are extensions of Chen's iterated integrals) of invariant differential forms.
Temperature and coupling dependence of the universal contact intensity for an ultracold Fermi gas
cond-mat.quant-gasF. Palestini, A. Perali, P. Pieri, G. C. Strinati
Physical properties of an ultracold Fermi gas in the temperature-coupling phase diagram can be characterized by the contact intensity C, which enters the pair-correlation function at short distances and describes how the two-body problem merges into its surrounding. We show that the local order established by pairing fluctuations about the critical temperatu
Hisashi Kasuya
We consider aspherical manifolds with torsion-free virtually polycyclic fundamental groups, constructed by Baues. We prove that if those manifolds are cohomologically symplectic then they are symplectic. As a corollary we show that cohomologically symplectic solvmanifolds are symplectic.
Jordi Guardia, Jesus Montes, Enric Nart
Let $K$ be the number field determined by a monic irreducible polynomial $f(x)$ with integer coefficients. In previous papers we parameterized the prime ideals of $K$ in terms of certain invariants attached to Newton polygons of higher order of the defining equation $f(x)$. In this paper we show how to carry out the basic operations on fractional ideals of $
Jacobo Pejsachowicz
We associate to a parametrized family $f$ of nonlinear Fredholm maps possessing a trivial branch of zeroes an {\it index of bifurcation} $β(f)$ which provides an algebraic measure for the number of bifurcation points from the trivial branch. The index $β(f)$ is derived from the index bundle of the linearization of the family along the trivial branch by means
J. Peer, A. Kendl
The electromagnetic pulses of rare long (order of seconds) repetitive lightning discharges near strike point (order of 100m) are analyzed and compared to magnetic fields applied in standard clinical transcranial magnetic stimulation (TMS) practice. It is shown that the time-varying lightning magnetic fields and locally induced potentials are in the same orde
Radu Ioan Bot, Sorin-Mihai Grad, Gert Wanka
With this note we bring again into attention a vector dual problem neglected by the contributions who have recently announced the successful healing of the trouble encountered by the classical duals to the classical linear vector optimization problem. This vector dual problem has, different to the mentioned works which are of set-valued nature, a vector obje
Mikaël Pichot, Thomas Schick, Andrzej Zuk
In this paper, we show how to construct examples of closed manifolds with explicitly computed irrational, even transcendental L2 Betti numbers, defined via the universal covering. We show that every non-negative real number shows up as an L2-Betti number of some covering of a compact manifold, and that many computable real numbers appear as an L2-Betti numbe
Christophe Cheverry, Isabelle Gallagher, Thierry Paul, Laure Saint-Raymond
In this work we prove that the shallow water flow, subject to strong wind forcing and linearized around an adequate stationary profile, develops for large times closed trajectories due to the propagation of Rossby waves, while Poincar\'e waves are shown to disperse. The methods used in this paper involve semi-classical analysis and dynamical systems for the
Masaaki Harada, Ching Hung Lam, Akihiro Munemasa
In this paper, we study the residue codes of extremal Type II Z_4-codes of length 24 and their relations to the famous moonshine vertex operator algebra. The main result is a complete classification of all residue codes of extremal Type II Z_4-codes of length 24. Some corresponding results associated to the moonshine vertex operator algebra are also discusse
M. Van den Nest
The theory of matchgates is of interest in various areas in physics and computer science. Matchgates occur in e.g. the study of fermions and spin chains, in the theory of holographic algorithms and in several recent works in quantum computation. In this paper we completely characterize the class of boolean functions computable by unitary two-qubit matchgate
Manuel Bodirsky, Peter Jonsson, Timo von Oertzen
We study techniques for deciding the computational complexity of infinite-domain constraint satisfaction problems. For certain fundamental algebraic structures Delta, we prove definability dichotomy theorems of the following form: for every first-order expansion Gamma of Delta, either Gamma has a quantifier-free Horn definition in Delta, or there is an eleme
A. Lascialfari, A. Rigamonti, L. Romanó
In this brief report an attempt is made for a 'mise-a-point' of the subject of the phase fluctuations of the superconducting order parameter above Tc in cuprates, particularly as they appear in underdoped compounds. Measurements of torque magnetometry, Nernst effect and isothermal diamagnetic magnetization curves published in the last years are taken
Manipulation of coherent atom waves using accelerated two-dimensional optical lattices
cond-mat.quant-gasWei-Chih Ting, Dian-Jiun Han, Shin-Tza Wu
We study the dynamics of Bose-Einstein condensates in accelerated two-dimensional optical square lattices by numerically solving the Gross-Pitaevskii equation. We consider the regime with negligible mean-field interactions and examine in detail the pulses of atom clouds ejected from the condensate due to Landau-Zener tunnelling. The pulses exhibit patterned
Sourav Chatterjee, Persi Diaconis, Allan Sly
Large graphs are sometimes studied through their degree sequences (power law or regular graphs). We study graphs that are uniformly chosen with a given degree sequence. Under mild conditions, it is shown that sequences of such graphs have graph limits in the sense of Lovász and Szegedy with identifiable limits. This allows simple determination of other featu
Masanori Ando, Takeshi Suzuki, Hiro-Fumi Yamada
A $q$-analogue of combinatorics concerning the Cartan matrix for the Iwahori-Hecke algebra of type $A$ is investigated. We give several descriptions for the determinant of the graded Cartan matrix, which imply some combinatorial identities. A conjectural expression for the elementary divisors is also presented.
Magnetic ground state of pyrochlore oxides close to metal-insulator boundary probed by muon spin rotation
cond-mat.str-elM. Miyazaki, R. Kadono, K. H. Satoh, M. Hiraishi
Magnetism of ruthernium pyrochlore oxides A2Ru2O7 (A = Hg, Cd, Ca), whose electronic properties within a localized ion picture are characterized by non-degenerate t2g orbitals (Ru5+, 4d3) and thereby subject to geometrical frustration, has been investigated by muon spin rotation/relaxation (muSR) technique. The A cation (mostly divalent) was varied to examin
Gabriel Abreu, Matt Visser
In any static spacetime the quasi-local Tolman mass contained within a volume can be reduced to a Gauss-like surface integral involving the flux of a suitably defined generalized surface gravity. By introducing some basic thermodynamics and invoking the Unruh effect one can then develop elementary bounds on the quasi-local entropy that are very similar in sp
Aaron W. Brown
We prove a result motivated by Williams's classification of expanding attractors and the Franks-Newhouse Theorem on codimension-1 Anosov diffeomorphisms: If a mixing hyperbolic attractor has 1-dimensional unstable manifolds then it is either is expanding or is homeomorphic to a compact abelian group (a toral solenoid); in the latter case the dynamics is
Third-order Asymptotic Optimality of the Generalized Shiryaev-Roberts Changepoint Detection Procedures
math.STAlexander G. Tartakovsky, Moshe Pollak, Aleksey S. Polunchenko
Several variations of the Shiryaev-Roberts detection procedure in the context of the simple changepoint problem are considered: starting the procedure at $R_0=0$ (the original Shiryaev-Roberts procedure), at $R_0=r$ for fixed $r>0$, and at $R_0$ that has a quasi-stationary distribution. Comparisons of operating characteristics are made. The differences fade
Lamei Yuan
This paper introduces the notion of Hom-Lie color algebra, which is a natural general- ization of Hom-Lie (super)algebras. Hom-Lie color algebras include also as special cases Lie (super) algebras and Lie color algebras. We study the homomorphism relation of Hom-Lie color algebras, and construct new algebras of such kind by a σ-twist. Hom-Lie color admissibl
Comparative Study of Asymmetry Origin of Galaxies in Different Environments. I. Optical observations
astro-ph.COI. Plauchu-Frayn, R. Coziol
This paper presents the first of two analyses about the influence of environment on the formation and evolution of galaxies observed in the nearby universe. For our study, we used three different samples representing different density environments: galaxies in Compact Groups (HCGs), Isolated Pairs of Galaxies (KPGs), and Isolated Galaxies (KIGs), which were
Shoji Yokura
The relative Grothendieck group $K_0(\m V/X)$ is the free abelian group generated by the isomorphism classes of complex algebraic varieties over $X$ modulo the "scissor relation". The motivic Hirzebruch class ${T_y}_*: K_0(\m V /X) \to H_*^{BM}(X) \otimes \bQ[y]$ is a unique natural transformation satisfying that for a nonsingular variety $X$ the val
Masashi Ando, Kentaro Doi, Hajime Susa
We investigate seed magnetic field generation in the early universe by radiation force of first stars. In the previous study with steady assumption, large amplitudes(10^{-15} G for first stars, 10^{-11}G for QSOs) are predicted. In this study, we formulate this issue in unsteady framework. Then, we consider a specific model of magnetic field generation aroun
Sumit Ganguly, Purushottam Kar
A data stream is viewed as a sequence of $M$ updates of the form $(\text{index},i,v)$ to an $n$-dimensional integer frequency vector $f$, where the update changes $f_i$ to $f_i + v$, and $v$ is an integer and assumed to be in $\{-m, ..., m\}$. The $p$th frequency moment $F_p$ is defined as $\sum_{i=1}^n \abs{f_i}^p$. We consider the problem of estimating $F_
Vineet Abhishek, Bruce Hajek
We study efficiency loss in Bayesian revenue optimal auctions. We quantify this as the worst case ratio of loss in the realized social welfare to the social welfare that can be realized by an efficient auction. Our focus is on auctions with single-parameter buyers and where buyers' valuation sets are finite. For binary valued single-parameter buyers with
Sumit Ganguly
For each $p \in (0,2]$, we present a randomized algorithm that returns an $ε$-approximation of the $p$th frequency moment of a data stream $F_p = \sum_{i = 1}^n \abs{f_i}^p$. The algorithm requires space $O(ε^{-2} \log (mM)(\log n))$ and processes each stream update using time $O((\log n) (\log ε^{-1}))$. It is nearly optimal in terms of space (lower bound $
Mobile Geometric Graphs, and Detection and Communication Problems in Mobile Wireless Networks
math.PRAlistair Sinclair, Alexandre Stauffer
Static wireless networks are by now quite well understood mathematically through the random geometric graph model. By contrast, there are relatively few rigorous results on the practically important case of mobile networks, in which the nodes move over time; moreover, these results often make unrealistic assumptions about node mobility such as the ability to
William Ballik, Kayll Lake
The invariant four-volume $\mathcal{V}$ of a complete black hole (the volume of the spacetime at and interior to the horizon) diverges. However, if one considers the black hole set up by the gravitational collapse of an object, and integrates only a finite time to the future of the collapse, the resultant volume is well defined and finite. In this paper we e
Apoorva Khare, Tim Ridenour
The paper is motivated by the study of graded representations of Takiff algebras, cominuscule parabolics, and their generalizations. We study certain special subsets of the set of weights (and of their convex hull) of the generalized Verma modules (or GVM's) of a semisimple Lie algebra $\lie g$. In particular, we extend a result of Vinberg and classify t
Yongle Yu
Supersolid helium has a rather low transition temperature and a small critical velocity, compared with liquid helium. These properties could be explained in terms of helium's spectrum structure and quantum jumps involving large momentum transfer. A grain in the solid helium possess valleys (local minima) in its many-body dispersion curve, and an exchange
Mass-Loss Timescale of Star Clusters in an External Tidal Field. II. Effect of Mass Profile of Parent Galaxy
astro-ph.GAAtaru Tanikawa, Toshiyuki Fukushige
We investigate the long-term dynamical evolution of star clusters in a steady tidal field produced by its parent galaxy. In this paper, we focus on the influence of mass profile of the parent galaxy. The previous studies were done with the simplification where the parent galaxy was expressed by point mass. We express different mass profiles of the parent gal
On the scaling rules for the anomaly-induced effective action of metric and electromagnetic field
hep-thAna M. Pelinson, Ilya L. Shapiro
The anomaly-induced effective action is a useful tool for deriving the contributions coming from quantum effects of massless conformal fields. It is well-known that such corrections in the higher derivative vacuum sector of the gravitational action provide the same exponential inflation (Starobinsky model) as the cosmological constant term. At the same time,
A. Deltuva, A. C. Fonseca
Nucleon transfer reactions in low-energy deuteron-deuteron scattering are described by solving exact four-particle equations in momentum space. The Coulomb interaction between the protons is included using the screening and renormalization method. Various realistic potentials are used between nucleon pairs. The energy dependence of the differential cross sec
Efficient computation of the cdf of the maximal difference between Brownian bridge and its concave majorant
stat.COFadoua Balabdaoui, Karim Filali
In this paper, we describe two computational methods for calculating the cumulative distribution function and the upper quantiles of the maximal difference between a Brownian bridge and its concave majorant. The first method has two different variants that are both based on a Monte Carlo approach, whereas the second uses the Gaver-Stehfest (GS) algorithm for
Jason Fulman
Combining Stein's method with heat kernel techniques, we show that the trace of the jth power of an element of U(n,C), USp(n,C) or SO(n,R) has a normal limit with error term of order j/n. In contrast to previous works, here j may be growing with n. The technique should prove useful in the study of the value distribution of approximate eigenfunctions of L
Michael P. Lamoureux, James A. Mingo, Sydney R. Pachmann
We determine numerically the self-similarity maps for spectra of the almost Mathieu operators, a two-dimensional fractal-like structure known as the Hofstadter butterfly. The similarity maps each have a horizontal component determined by certain algebraic maps, and vertical component determined by a Mobius transformation, indexed by a semigroup of the matrix
Michael P. Lamoureux
Plotting spectra of a range of almost Mathieu operators reveals a beautiful fractal-like image that contains multiple copies of a butterfly image. We demonstrate that plotting the butterflies using a gap-labelling scheme based on K-theory or Chern numbers reveals systematic discontinuities in the gap positioning. A proper image is produced only when we take
Boldizsar Kalmar, Tamas Terpai
We obtain relations among the characteristic classes of a manifold M admitting corank one maps. Our relations yield strong restrictions on the cobordism class of M and also nonexistence results for singular maps of the projective spaces. We obtain our results through blowing up a manifold along the singular set of a smooth map and perturbing the arising non-
Brian J. Williams
Interstellar dust grains play a crucial role in the evolution of the galactic interstellar medium (ISM). Despite its importance, however, dust remains poorly understood in terms of its origin, composition, and abundance throughout the universe. Supernova remnants (SNRs) provide a laboratory for studying the evolution of dust grains, as they are one of the on
Andrew Randono
The most prominent realization of gravity as a gauge theory similar to the gauge theories of the standard model comes from enlarging the gauge group from the Lorentz group to the de Sitter group. To regain ordinary Einstein-Cartan gravity the symmetry must be broken, which can be accomplished by known quasi-dynamic mechanisms. Motivated by symmetry breaking
Paolo Frasca, Fabio Fagnani
In this paper we study two related iterative randomized algorithms for distributed computation of averages. The first one is the recently proposed Broadcast Gossip Algorithm, in which at each iteration one randomly selected node broadcasts its own state to its neighbors. The second algorithm is a novel de-synchronized version of the previous one, in which at
Simone Mercuri, Andrew Randono
The Barbero-Immirzi parameter is a one parameter quantization ambiguity underpinning the loop approach to quantum gravity that bears tantalizing similarities to the theta parameter of gauge theories such as Yang-Mills and QCD. Despite the apparent semblance, the Barbero-Immirzi field has resisted a direct topological interpretation along the same lines as th
R. de la Madrid
Whenever the Breit-Wigner amplitude appears in a calculation,there are many instances (e.g., Fermi's two-level system and the Weisskopf-Wigner approximation) where energy integrations are extended from the scattering spectrum of the Hamiltonian to the whole real line. Such extensions are performed in order to obtain a desirable, causal result. In this pa
Sayantani Bhattacharyya, Shiraz Minwalla, Kyriakos Papadodimas
We study small hairy black holes in a consistent truncation of ${\cal N}=8$ gauged supergravity that consists of a single charged scalar field interacting with the metric and a U(1) gauge field. Small very near extremal RNAdS black holes in this system are unstable to decay by superradiant emission. The end point of this instability is a small hairy black ho
Antonio Delgado, Christopher Kolda, J. Pocahontas Olson, Alejandro de la Puente
We present a generalization of the Next-to-Minimal Supersymmetric Standard Model (NMSSM), with an explicit mu-term and a supersymmetric mass for the singlet superfield, as a route to alleviating the little hierarchy problem of the Minimal Supersymmetric Standard Model (MSSM). Though this model does not address the mu-problem of the MSSM, we are able to gener
J. M. Chow, L. DiCarlo, J. M. Gambetta, F. Motzoi
We employ pulse shaping to abate single-qubit gate errors arising from the weak anharmonicity of transmon superconducting qubits. By applying shaped pulses to both quadratures of rotation, a phase error induced by the presence of higher levels is corrected. Using a derivative of the control on the quadrature channel, we are able to remove the effect of the a
Parvis Soltan-Panahi, Julian Struck, Philipp Hauke, Andreas Bick
Periodicity is one of the most fundamental structural characteristics of systems occurring in nature. The properties of these systems depend strongly on the symmetry of the underlying periodic structure. In solid state materials - for example - the static and transport properties as well as the magnetic and electronic characteristics are crucially influenced
Fred W. Helenius
For certain Lie algebras g, we can use a Z/5Z-grading and define a quartic form and a skew-symmetric bilinear form on the degree 1 component, g_1, thereby constructing a Freudenthal triple system. The structure of the Freudenthal triple system is examined using root system methods available in the Lie algebra context. In the cases g = E_8 (where g_1 is the m
Dejan Kolarič
We prove the parametric homotopy principle for holomorphic immersions of Stein manifolds into Euclidian space and the homotopy principle with approximation on holomorphically convex sets. We write an integration by parts like formula for the solution $f$ to the problem $Lf|_Σ=g$, where $L$ is a holomorphic vector field, semi-transversal to analytic variety $
Vera V. Serganova, Alexei N. Skorobogatov
Let X be a del Pezzo surface of degree 1, and let G be the simple Lie group of type E_8. We construct a locally closed embedding of a universal torsor over X into the G-orbit of the highest weight vector of the adjoint representation. This embedding is equivariant with respect to the action of the Neron-Severi torus T of X identified with a maximal torus of
Exact solution for a diffusive nonequilibrium steady state of an open quantum chain
cond-mat.stat-mechMarko Znidaric
We calculate a nonequilibrium steady state of a quantum XX chain in the presence of dephasing and driving due to baths at chain ends. The obtained state is exact in the limit of weak driving while the expressions for one- and two-point correlations are exact for an arbitrary driving strength. In the steady state the magnetization profile and the spin current
Supersolid and charge density-wave states from anisotropic interaction in an optical lattice
cond-mat.quant-gasY. -H. Chan, Y. -J. Han, L. -M. Duan
We show anisotropy of the dipole interaction between magnetic atoms or polar molecules can stabilize new quantum phases in an optical lattice. Using a well controlled numerical method based on the tensor network algorithm, we calculate phase diagram of the resultant effective Hamiltonian in a two-dimensional square lattice - an anisotropic Hubbard model of h
Mark Reynolds, Jon Miller
We present two Suzaku observations of the Galactic center microquasar 1E 1740.7-2942 separated by approximately 700 days. The source was observed on both occasions after a transition to the spectrally hard state. Significant emission from 1E 1740.7-2942 is detected out to an energy of 300 keV, with no spectral break or turnover evident in the data. We tentat
D. P. Kosimov, A. A. Dzhurakhalov, F. M. Peeters
The lowest energy configurations of Cn(n =< 55) clusters are obtained using the energy mini- mization technique with the conjugate gradient (CG) method where a modified Brenner potential is invoked to describe the carbon and hydrocarbon interaction. We found that the ground state configuration consists of a single ring for small number of C atoms and multi-r
Filippo Simini, Tommaso Anfodillo, Marco Carrer, Jayanth R. Banavar
Ecological communities exhibit pervasive patterns and inter-relationships between size, abundance, and the availability of resources. We use scaling ideas to develop a unified, model-independent framework for understanding the distribution of tree sizes, their energy use and spatial distribution in tropical forests. We demonstrate that the scaling of the tre
Molecular gas chemistry in AGN. II. High-resolution imaging of SiO emission in NGC1068: shocks or XDR?
astro-ph.COS. Garcia-Burillo, A. Usero, A. Fuente, J. Martin-Pintado
This paper is part of a multi-species survey of line emission from the molecular gas in the circum-nuclear disk (CND) of the Seyfert 2 galaxy NGC1068. Single-dish observations have provided evidence that the abundance of silicon monoxide(SiO) in the CND of NGC1068 is enhanced by 3-4 orders of magnitude with respect to the values typically measured in quiesce
S. McEndoo, Th. Busch
We investigate the dynamics of linear vortex lattices in anisotropic traps in two-dimensions and show that the interplay between the rotation and the anisotropy leads to a rich but highly regular dynamics.
R. Visser, C. P. Dullemond
Models of the formation, evolution and photoevaporation of circumstellar disks are an essential ingredient in many theories of the formation of planetary systems. The ratio of disk mass over stellar mass in the circumstellar phase of a disk is largely determined by the angular momentum of the original cloud core from which the system was formed. While full 3
Bindiya Arora, M. S. Safronova, Charles W. Clark
We propose a scheme for state-insensitive trapping of neutral atoms by using light with two independent wavelengths. In particular, we describe the use of trapping and control lasers to minimize the variance of the potential experienced by a trapped Rb atom in ground and excited states. We present calculated values of wavelength pairs for which the 5s and 5p
A. Küpcü Yoldaş, J. Greiner, S. Klose, T. Krühler
We analyse the properties of the host galaxy of the optically dark gamma-ray burst (GRB) 020819 (z = 0.41) and discuss the possible implications in the context of "dark" GRBs. We present g'r'i'z'JHK photometry of the host galaxy and fit the broad spectral energy distribution including the public Spitzer IRAC data using stellar populat
Cristian Ion
We compute the reduced Gröbner basis of the toric ideal with respect to a suitable monomial order and we study the Hilbert series of the vertex cover algebra $A(G)$, where $G$ is an unmixed bipartite graph without isolated vertices.
G. L. Litvinov, V. P. Maslov, A. Ya. Rodionov, A. N. Sobolevski
This is a survey paper on applications of mathematics of semirings to numerical analysis and computing. Concepts of universal algorithm and generic program are discussed. Relations between these concepts and mathematics of semirings are examined. A very brief introduction to mathematics of semirings (including idempotent and tropical mathematics) is presente
Matt DeLand
Given a morphism between smooth projective varieties $f: W \to X$, we study whether $f$-relatively free rational curves imply the existence of $f$-relatively very free rational curves. The answer is shown to be positive when the fibers of the map $f$ have Picard number 1 and a further smoothness assumption is imposed. The main application is when $X \subset
Grigory L. Litvinov
A brief introduction to tropical and idempotent mathematics (with an emphasys on idempotent functional analysis) is presented. Applications to classical mechanics and geometry are especially examined.
Effect of ferromagnetic film thickness on magnetoresistance of thin-film superconductor-ferromagnet hybrids
cond-mat.supr-conA. Yu. Aladyshkin, A. P. Volodin, V. V. Moshchalkov
We study the influence of the thickness Df of the plain ferromagnetic (F) film on the electrical resistance of the flux-coupled hybrids, consisting of superconducting (S) Al film and multilayer [Co/Pt] F film with out-of-plain magnetization. The behavior of such hybrids at high and low temperatures is found to be different: the nucleation of superconductivit
A. Beraudo, J. P. Blaizot, P. Faccioli, G. Garberoglio
We propose a model for the propagation of a heavy-quark in a hot plasma, to be viewed as a first step towards a full description of the dynamics of heavy quark systems in a quark-gluon plasma, including bound state formation. The heavy quark is treated as a non relativistic particle interacting with a fluctuating field, whose correlator is determined by a ha
Alok Kumar Pan, Dipankar Home
Using measurements pertaining to a suitable Mach-Zehnder(MZ) type setup, a curious quantum mechanical effect of contextuality between the path and the polarization degrees of freedom of a polarized photon is demonstrated, without using any notion of realism or hidden variables - an effect that holds good for the product as well as the entangled states. This
Kimberly Hopkins
Split-CM points are points of the moduli space h_2/Sp_4(Z) corresponding to products $E \times E'$ of elliptic curves with the same complex multiplication. We prove that the number of split-CM points in a given class of h_2/Sp_4(Z) is related to the coefficients of a weight 3/2 modular form studied by Eichler. The main application of this result is a for
CdWO4 scintillating bolometer for Double Beta Decay: Light and Heat anticorrelation, light yield and quenching factors
nucl-exC. Arnaboldi, J. W. Beeman, O. Cremonesi, L. Gironi
We report the performances of a 0.51 kg CdWO4 scintillating bolometer to be used for future Double Beta Decay Experiments. The simultaneous read-out of the heat and the scintillation light allows to discriminate between different interacting particles aiming at the disentanglement and the reduction of background contribution, key issue for next generation ex
Heterointerface effects on the charging energy of shallow D- ground state in silicon: the role of dielectric mismatch
cond-mat.mes-hallM. J. Calderon, J. Verduijn, G. P. Lansbergen, G. C. Tettamanzi
Donor states in Si nanodevices can be strongly modified by nearby insulating barriers and metallic gates. We report here experimental results indicating a strong reduction in the charging energy of isolated As dopants in Si FinFETs relative to the bulk value. By studying the problem of two electrons bound to a shallow donor within the effective mass approach
P. Napolitani, F. Rejmund, L. Tassan-Got, M. V. Ricciardi
New data from GSI on the production-cross-section for fragmentation of the systems 56Fe+p and 56Fe+Ti at 1 A GeV revealed the appearance of even-odd staggering in the cross-section distribution for chains of isotopes with given N-Z. The staggering is strongly enhanced for the chain N=Z, it reduces as the production moves away from the N=Z chain, and it rever
Raman light scattering study and microstructural analysis of epitaxial films of the electron-doped superconductor La_{2-x}Ce_{x}CuO_{4}
cond-mat.supr-conM. Rahlenbeck, M. Wagenknecht, A. Tsukada, D. Koelle
We present a detailed temperature-dependent Raman light scattering study of optical phonons in molecular-beam-epitaxy-grown films of the electron-doped superconductor La_{2-x}Ce_{x}CuO_{4} close to optimal doping (x ~ 0.08, T_c = 29 K and x ~ 0.1, T_c = 27 K). The main focus of this work is a detailed characterization and microstructural analysis of the film
High dispersion spectroscopy of two A supergiant systems in the Small Magellanic Cloud with novel properties
astro-ph.SRR. E. Mennickent, M. A. Smith
We present the results of a spectroscopic investigation of two novel variable bright blue stars in the SMC, OGLE004336.91-732637.7 (SMC-SC3) and the periodically occulted star OGLE004633.76-731204.3 (SMC-SC4), whose photometric properties were reported by Mennickent et al. (2010). High-resolution spectra in the optical and far-UV show that both objects are a
New Physics at the LHC. A Les Houches Report: Physics at TeV Colliders 2009 - New Physics Working Group
hep-phG. Brooijmans, C. Grojean, G. D. Kribs, C. Shepherd-Themistocleous
We present a collection of signatures for physics beyond the standard model that need to be explored at the LHC. First, are presented various tools developed to measure new particle masses in scenarios where all decays include an unobservable particle. Second, various aspects of supersymmetric models are discussed. Third, some signatures of models of strong
Secondary structure of Ac-Ala$_n$-LysH$^+$ polyalanine peptides ($n$=5,10,15) in vacuo: Helical or not?
physics.bio-phM. Rossi, V. Blum, P. Kupser, G. von Helden
The polyalanine-based peptide series Ac-Ala_n-LysH+ (n=5-20) is a prime example that a secondary structure motif which is well-known from the solution phase (here: helices) can be formed in vacuo. We here revisit this conclusion for n=5,10,15, using density-functional theory (van der Waals corrected generalized gradient approximation), and gas-phase infrared
Javier Sesma
Recently, it has been proved that a nonlinear quantum oscillator, generalization of the isotonic one, is exactly solvable for certain values of its parameters. Here we show that the Schroedinger equation for such an oscillator can be transformed into a confluent Heun equation. We give a very simple and efficient algorithm to solve it numerically, no matter w
Erika Andersson, Stig Stenholm
We have earlier constructed a generalized entropy concept to show the direction of time in an evolution following from a Markov generator. In such a dynamical system, the entity found changes in a monotonic way starting from any initial state of the system. In this paper, we generalize the treatment to the case when population is pumped into the system from
D. J. Urminsky
Errors in numerical simulations of gravitating systems can be magnified exponentially over short periods of time. Numerical shadowing provides a way of demonstrating that the dynamics represented by numerical simulations are representative of true dynamics. Using the Sitnikov Problem as an example, it is demonstrated that unstable orbits of the 3-body proble
J. J. Stead, M. G. Hoare
Using near infrared UKIDSS Galactic Plane Survey data, we make extinction measurements to individual stars along the same line of sight as molecular clouds. Using an existing 3D extinction map of the inner Galaxy, that provides line of sight specific extinction-distance relationships, we convert the measured extinction of molecular clouds to a corresponding
Anita Eusebi, Stefano Mancini
We introduce a new control strategy on a two-way deterministic cryptographic scheme, which relies on a suitable unitary transformation rather than quantum measurement. The study is developed for d-ary alphabets and the particular choice of the transformation works when d is an odd prime power. It leads to an improvement of the protocol security, which we pro
Xian Gao
Non-linear CMB temperature anisotropies up to the third-order on large scales are calculated. On large scales and in the Sachs-Wolfe limit, we give the explicit expression for the observed temperature anisotropy in terms of the primordial curvature perturbation up to the third-order. We derived the final bispectrum and trispectrum of anisotropies and the cor
Gul-Mirza Kerimov, Alberto Ventura
Bound and scattering states of a non-central extension of the three-dimensional Kepler-Coulomb Hamiltonian are worked out analytically within the framework of the potential groups of the problem, SO(7) for bound states and SO(6,1) for scattering states. In the latter case, the S matrix is calculated by the method of intertwining operators.
Laurent Bordes, Christian Paroissin, Ali Salami
We consider the gamma process perturbed by a Brownian motion (independent of the gamma process) as a degradation model. Parameters estimation is studied here. We assume that $n$ independent items are observed at irregular instants. From these observations, we estimate the parameters using the moments method. Then, we study the asymptotic properties of the es
G. Sardanashvily
Relativistic mechanics on an arbitrary manifold is formulated in the terms of jets of its one-dimensional submanifolds. A generic relativistic Lagrangian is constructed. Relativistic mechanics on a pseudo-Riemannian manifold is particularly considered.