March 2008 arXiv papers — page 8

Gloria Mari Beffa

In this paper we present an overview of the connection between completely integrable systems and the background geometry of the flow. This relation is better seen when using a group-based concept of moving frame introduced by Fels and Olver in [Acta Appl. Math. 51 (1998), 161-213; 55 (1999), 127-208]. The paper discusses the close connection between differen

B. Basu, S. Dhar, S. Chatterjee

We have studied the physics of atoms with permanent electric dipole moment and non vanishing magnetic moment interacting with an electric field and inhomogeneous magnetic field. This system can be demonstrated as the atomic analogue of Landau quantization of charged particles in a uniform magnetic field. This Landau-like atomic problem is also studied with s

Bradley Efron

Modern statisticians are often presented with hundreds or thousands of hypothesis testing problems to evaluate at the same time, generated from new scientific technologies such as microarrays, medical and satellite imaging devices, or flow cytometry counters. The relevant statistical literature tends to begin with the tacit assumption that a single combined

J. Fujioka, S. Miyasaka, Y. Tokura

The doping variation of charge and orbital dynamics in perovskite-type Y1-xCaxVO3 (0<x<0.1) is investigated by measurements of the optical conductivity and Raman scattering spectra in comparison with the larger-bandwidth system La1-xSrxVO3. We also take into consideration the magnitude of the GdFeO3-type orthorhombic lattice distortion, which is large and sm

Alessandro Barducci, Giovanni Bussi, Michele Parrinello

We present a method for determining the free energy dependence on a selected number of collective variables using an adaptive bias. The formalism provides a unified description which has metadynamics and canonical sampling as limiting cases. Convergence and errors can be rigorously and easily controlled. The parameters of the simulation can be tuned so as to

Jiao Wang, Anders S. Mouritzen, Jiangbin Gong

Controlling the translational motion of cold atoms using optical lattice potentials is of both theoretical and experimental interest. By designing two on-resonance time sequences of kicking optical lattice potentials, a novel connection between two paradigms of nonlinear mapping systems, i.e., the kicked rotor model and the kicked Harper model, is establishe

Kenneth W. Cavagnolo, Megan Donahue, G. Mark Voit, Ming Sun

We explore the band dependence of the inferred X-ray temperature of the intracluster medium (ICM) for 192 well-observed galaxy clusters selected from the Chandra Data Archive. If the hot ICM is nearly isothermal in the projected region of interest, the X-ray temperature inferred from a broad-band (0.7-7.0 keV) spectrum should be identical to the X-ray temper

R. G. T. Zegers, R. Meharchand, T. Adachi, Sam M. Austin

The 24Mg(3He,t)24Al reaction has been studied at E(3He)=420 MeV. An energy resolution of 35 keV was achieved. Gamow-Teller strengths to discrete levels in 24Al are extracted by using a recently developed empirical relationship for the proportionality between Gamow-Teller strengths and differential cross sections at zero momentum transfer. Except for small di

Shijong Ryang

By applying the conformal SO(2,4) transformations to the folded rotating string configuration with two spins given by a certain limit from the helical string solution in AdS_3 x S^1, we construct new string solutions whose energy-spin relations are characterized by the boost parameter. When two SO(2,4) transformations are performed with two boost parameters

Patrick Weltevrede, Ben Stappers, R. T. Edwards

A large sample of about two hundred pulsars have been observed to study their subpulse modulation at an observing wavelength of (when achievable) both 21 and 92 cm using the Westerbork Synthesis Radio Telescope. For 57 pulsars drifting subpulses are discovered for the first time and are confirmed for many others. This leads to the conclusion that it could we

C. L. Barbosa, R. D. Blum, P. S. Conti, A. Damineli

We present $K$-band spectra of the near infrared counterparts to IRS2E and IRS2W which is associated with the ultracompact HII region W51d, both of them embedded sources in the Galactic compact HII region W51 IRS2. The high spatial resolution observations were obtained with the laser guide star facility and Near infrared Integral Field Spectrograph (NIFS) mo

Arnaud Durand

We investigate the large intersection properties of the set of points that are approximated at a certain rate by a family of affine subspaces. We then apply our results to various sets arising in the metric theory of Diophantine approximation, in the study of the homeomorphisms of the circle and in the perturbation theory for Hamiltonian systems.

Cesar Meirelles Filho

We have analyzed pair production in the innermost region of a two-temperature external soft photon comptonized accretion disk. We have shown that, if the viscosity parameter is greater than a temperature and r dependent critical value, the solution to the disk equation is double valued: one, advection dominated and the other, radiation dominated. When the vi

K. Sasaki, R. Saito, G. Dresselhaus, M. S. Dresselhaus

The quantum corrections to the frequencies of the $Γ$ point longitudinal optical (LO) and transverse optical (TO) phonon modes in carbon nanotubes are investigated theoretically. The frequency shift and broadening of the TO phonon mode strongly depend on the curvature effect due to a special electron-phonon coupling in carbon nanotubes, which is shown by the

Alicia Dickenstein, Laura Felicia Matusevich, Ezra Miller

An explicit lattice point realization is provided for the primary components of an arbitrary binomial ideal in characteristic zero. This decomposition is derived from a characteristic-free combinatorial description of certain primary components of binomial ideals in affine semigroup rings, namely those that are associated to faces of the semigroup. These res

L. Gizon

Solar oscillations consist of a rich spectrum of internal acoustic waves and surface gravity waves, stochastically excited by turbulent convection. They have been monitored almost continuously over the last ten years with high-precision Doppler images of the solar surface. The purpose of helioseismology is to retrieve information about the structure and the

Akihiro Suzuki, Toshikazu Shigeyama

A novel method to derive stationary solutions of the Vlasov-Maxwell system is established. This method is based on the assumption that the deviation of the velocity distribution from the Maxwell-Boltzmann distribution can be expanded by the Hermite polynomials. By applying our method, a new two-dimensional equilibrium is derived, which may provide an initial

L. C. Osborne, S. E. Palmer, S. G. Lisberger, W. Bialek

To evaluate the nature of the neural code in the cerebral cortex, we have used a combination of theory and experiment to assess how information is represented in a realistic cortical population response. We have shown how a sensory stimulus could be estimated on a biologically-realistic time scale, given brief individual responses from a population of neuron

Fernando D. Gaspoz, Pedro Morin

In this article we prove that it is possible to construct, using newest-vertex bisection, meshes that equidistribute the error in $H^1$-norm, whenever the function to approximate can be decomposed as a sum of a regular part plus a singular part with singularities around a finite number of points. This decomposition is usual in regularity results of Partial D

Tao Han, Rakhi Mahbubani, Devin G. E. Walker, Lian-Tao Wang

We study methods of extracting new physics signals in final states with a top-quark pair plus large missing energy at the LHC. We consider two typical examples of such new physics: pair production of a fermionic top partner (a $T&#39;$ in Little Higgs models for example) and of a scalar top partner (a $\tilde{t}$ in SUSY). With a commonly-adopted discrete sy

Xiangmin Jiao, Hongyuan Zha

Differential quantities, including normals, curvatures, principal directions, and associated matrices, play a fundamental role in geometric processing and physics-based modeling. Computing these differential quantities consistently on surface meshes is important and challenging, and some existing methods often produce inconsistent results and require ad hoc

Boris Bukh

We asymptotically determine the size of the largest family F of subsets of {1,...,n} not containing a given poset P if the Hasse diagram of P is a tree. This is a qualitative generalization of several known results including Sperner&#39;s theorem.

Ted Dunning

Two meta-evolutionary optimization strategies described in this paper accelerate the convergence of evolutionary programming algorithms while still retaining much of their ability to deal with multi-modal problems. The strategies, called directional mutation and recorded step in this paper, can operate independently but together they greatly enhance the abil

E. Gomez

The magnitude of the angular momentum ($J^2$) in quantum mechanics is larger than expected from a classical model. We explain this deviation in terms of quantum fluctuations. A standard quantum mechanical calculation gives the correct interpretation of the components of the angular momentum in the vector model in terms of projections and fluctuations. We sho

D. Francia, J. Mourad, A. Sagnotti

We determine the current exchange amplitudes for free totally symmetric tensor fields $\vf_{μ_1 ... μ_s}$ of mass $M$ in a $d$-dimensional $dS$ space, extending the results previously obtained for $s=2$ by other authors. Our construction is based on an unconstrained formulation where both the higher-spin gauge fields and the corresponding gauge parameters $Λ

Keshav Dasgupta, Hassan Firouzjahi, Rhiannon Gwyn

We study the axion in a warped heterotic background. It is shown that the axion decay constant, f_a, is sensitive to the warped mass scale of the throat. As an explicit model, we construct a novel AdS-like geometry in heterotic string theory. We demonstrate that in this background f_a is given by the mass scale of the longest throat in the compactification.

E. Geis, V. Ziskin, T. Akdogan, H. Arenhoevel

We report new measurements of the neutron charge form factor at low momentum transfer using quasielastic electrodisintegration of the deuteron. Longitudinally polarized electrons at an energy of 850 MeV were scattered from an isotopically pure, highly polarized deuterium gas target. The scattered electrons and coincident neutrons were measured by the Bates L

Oscar Randal-Williams

Combining results of Wahl, Galatius--Madsen--Tillmann--Weiss and Korkmaz one can identify the homotopy-type of the classifying space of the stable non-orientable mapping class group $N_\infty$ (after plus-construction). At odd primes p, the F_p-homology coincides with that of $Q_0(HP^\infty_+)$, but at the prime 2 the result is less clear. We identify the F_

Yang Qi, Cenke Xu

We propose quantum phase transitions beyond the Landau&#39;s paradigm of Sp(4) spin Heisenberg models on the triangular and square lattices, motivated by the exact Sp(4)$\simeq$ SO(5) symmetry of spin-3/2 fermionic cold atomic system with only $s-$wave scattering. On the triangular lattice, we study a phase transition between the $\sqrt{3}\times\sqrt{3}$ spi

Youhei Masada, Shigehiro Nagataki, Kazunari Shibata, Toshio Terasawa

We present a theoretical model describing magnetar giant flares on the basis of solar flare/coronal mass ejection theory. In our model, a preflare activity plays a crucial role in driving evaporating flows and supplying baryonic matters into the magnetosphere. The loaded baryonic matter, that is called &#34;prominence&#34;, is then gradually uplifted via cru

Jonas T. Hartwig

Using the language of h-Hopf algebroids which was introduced by Etingof and Varchenko, we construct a dynamical quantum group, F_ell(GL(n)), from the elliptic solution of the quantum dynamical Yang-Baxter equation with spectral parameter associated to the Lie algebra sl_n. We apply the generalized FRST construction and obtain an h-bialgebroid F_ell(M(n)). Na

Randall L. Cooper

I construct a simple model of the convective burning layer during a type I X-ray burst to investigate the effects convection has on the stability of the layer to nonradial oscillations. A linear perturbation analysis demonstrates that the region is stable to nonradial oscillations when energy transport is convection-dominated, but it is unstable when energy

Victor Ginzburg, Travis Schedler, Boris Tsygan

We present a new approach to cyclic homology that does not involve the Connes differential and is based on a `noncommutative equivariant de Rham complex&#39; of an associative algebra. The differential in that complex is a sum of the Karoubi-de Rham differential, which replaces the Connes differential, and another operation analogous to contraction with a ve

Mark Van Raamsdonk

We study the SO(8) superconformal theory proposed recently by Bagger and Lambert as a possible worldvolume theory for multiple M2-branes. For their explicit example with gauge group SO(4), we rewrite the theory (originally formulated in terms of a three-algebra) as an ordinary SU(2) \times SU(2) gauge theory with bifundamental matter. In this description, th

Sebastiano Bernuzzi, Alessandro Nagar

In this work we discuss the time-evolution of nonspherical perturbations of a nonrotating neutron star described by a realistic Equation of State (EOS). We analyze 10 different EOS for a large sample of neutron star models. Various kind of generic initial data are evolved and the corresponding gravitational wave signals are computed. We focus on the dynamica

Keith Copsey, Robert B. Mann

We develop a careful definition of energy for nonsupersymmetric warped product asymptotically $AdS_d \times M_q$ solutions which include a nonzero p-form. In the case of an electric p-form extending along all the AdS directions, and in particular in the case of self-dual fields like those used in the Freund-Rubin construction, the Hamiltonian is well defined

Anthony H. Gonzalez, Doug Clowe, Marusa Bradac, Dennis Zaritsky

We present evidence for a Spitzer-selected luminous infrared galaxy (LIRG) behind the Bullet Cluster. The galaxy, originally identified in IRAC photometry as a multiply imaged source, has a spectral energy distribution consistent with a highly extincted (A_V~3.3), strongly star-forming galaxy at z=2.7. Using our strong gravitational lensing model presented i

Natalya A. Zimbovskaya

We explore electron transport through a quantum dot coupled to the source and drain charge reservoirs We trace the transition from the Coulomb blockade regime to Kondo regime in the electron transport through the dot occuring when we gradually strengthen the coupling of the dot to the charge reservoirs. The current-voltage $(I-V)$ characteristics are calcula

Franck van Breugel, Babita Sharma, James Worrell

Desharnais, Gupta, Jagadeesan and Panangaden introduced a family of behavioural pseudometrics for probabilistic transition systems. These pseudometrics are a quantitative analogue of probabilistic bisimilarity. Distance zero captures probabilistic bisimilarity. Each pseudometric has a discount factor, a real number in the interval (0, 1]. The smaller the dis

Guillaume Blanc, Laura Greggio

Using an extensive compilation of literature supernova rate data we study to which extent its evolution constrains the star formation history, the distribution of the type Ia supernova (SNIa) progenitor&#39;s lifetime, the mass range of core-collapse supernova (CCSN) progenitors, and the evolution of the iron density in the field. We find that the diagnostic

Thomas Jorg, Helmut G. Katzgraber

We perform Monte Carlo simulations of Ising spin-glass models in three and four dimensions, as well as of Migdal-Kadanoff spin glasses on a hierarchical lattice. Our results show strong evidence for universal scaling in the spin-glass phase in all three models. Not only does this allow for a clean way to compare results obtained from different coupling distr

S. H. Florez, J. A. Katine, M. Carey, L. Folks

The impact of radiofrequency (rf) currents on the direct current (dc) driven switching dynamics in current-perpendicular-to-plane nanoscale spin valves is demonstrated. The rf currents dramatically alter the dc driven free layer magnetization reversal dynamics as well as the dc switching level. This occurs when the frequency of the rf current is tuned to a f

G. F. Chen, Z. Li, D. Wu, G. Li

A series of layered CeO$_{1-x}$F$_x$FeAs compounds with x=0 to 0.20 are synthesized by solid state reaction method. Similar to the LaOFeAs, the pure CeOFeAs shows a strong resistivity anomaly near 145 K, which was ascribed to the spin-density-wave instability. F-doping suppresses this instability and leads to the superconducting ground state. Most surprising

Juan Miguel Ruiz

Let (M, g) be a closed Riemannian manifold and gE the Euclidean metric. We show that for m > 1, (M x R^m, (g + gE)) is not conformal to a positive Einstein manifold. Moreover, (M x R^m, (g + gE)) is not conformal to a Riemannian manifold of positive Ricci curvature, through a smooth, radial, positive, integrable function of R^m, for m > 1. These results are

Edmund Landau

This is an English translation of Edmund Landau&#39;s Doctoral Dissertation.

Alexey Voevodkin, Christopher J. Miller, Konstantin Borozdin, Katrin Heitmann

We present a combined optical and X-ray analysis of three optically selected X-ray bright groups with giant elliptical galaxies in the center. These massive ellipticals were targeted for XMM-Newton X-ray observations based on their large velocity dispersions and their proximity to a nearby ROSAT X-ray source. Additionally, these targets are significantly bri

Federico Camia, Matthijs Joosten, Ronald Meester

It is natural to expect that there are only three possible types of scaling limits for the collection of all percolation interfaces in the plane: (1) a trivial one, consisting of no curves at all, (2) a critical one, in which all points of the plane are surrounded by arbitrarily large loops and every deterministic point is almost surely surrounded by a count

L. L. Vaksman

This is Leonid Vaksman&#39;s monograph &#34;Quantum bounded symmetric domains&#34; (in Russian), preceded with an English translation of the table of contents and (a part) of the introduction. Quantum bounded symmetric domains are interesting from several points of view. In particular, they provide interesting examples for noncommutative complex analysis (i.

Charles Schwartz

Here we follow the basic analysis that is common for real and complex variables and find how it can be applied to a quaternionic variable. Non-commutativity of the quaternion algebra poses obstacles for the usual manipulations; but we show how many of those obstacles can be overcome. After a tiny bit of linear algebra we look at the beginnings of differentia

Rustam Sadykov

For each integer q>0 there is a cohomology theory such that the zero cohomology group of a manifold N of dimension n is a certain group of cobordism classes of proper fold maps of manifolds of dimension n+q into N. We prove a splitting theorem for the spectrum representing the cohomology theory of fold maps. For even q, the splitting theorem implies that the

Vitaly Skachek, Mark F. Flanagan

We present lower bounds on the minimum pseudocodeword effective Euclidean distance (or minimum &#34;pseudodistance&#34;) for coded modulation systems using linear codes with $q$-ary phase-shift keying (PSK) modulation over the additive white Gaussian noise (AWGN) channel. These bounds apply to both binary and nonbinary coded modulation systems which use dire

Rafael F. Wyrembelski, Tobias J. Oechtering, Igor Bjelakovic, Clemens Schnurr

We consider the broadcast phase of a three-node network, where a relay node establishes a bidirectional communication between two nodes using a spectrally efficient two-phase decode-and-forward protocol. In the first phase the two nodes transmit their messages to the relay node. Then the relay node decodes the messages and broadcasts a re-encoded composition

Lado Samushia, Bharat Ratra

We use the Allen et al. (2008) galaxy cluster gas mass fraction versus redshift data to constrain parameters of three different dark energy models: a cosmological constant dominated one ($Λ$CDM); the XCDM parameterization of dark energy; and a slowly-rolling scalar field model with inverse-power-law potential energy density. (Instead of using the Monte Carlo

Matthias Opel, Karl-Wilhelm Nielsen, Sebastian Bauer, Sebastian T. B. Goennenwein

The existence of semiconductors exhibiting long-range ferromagnetic ordering at room temperature still is controversial. One particularly important issue is the presence of secondary magnetic phases such as clusters, segregations, etc... These are often tedious to detect, leading to contradictory interpretations. We show that in our cobalt doped ZnO films gr

Rebecca N. Palmer, Alexander Klein, Dieter Jaksch

We explore the behavior of interacting bosonic atoms in an optical lattice subject to a large artificial magnetic field. We extend earlier investigations of this system where the number of magnetic flux quanta per unit cell alpha is close to a simple rational number [Phys. Rev. Lett. 96, 180407 (2006)]. Interesting topological states such as the Laughlin and

N. B. Kopnin, E. B. Sonin

Possible superconductivity of electrons with the Dirac spectrum is analyzed using the BCS model. We calculate the critical temperature, the superconducting energy gap, and supercurrent as functions of the doping level and of the pairing interaction strength. Zero doping is characterized by existence of the quantum critical point such that the critical temper

Matteo Beccaria, Valentina Forini

A recently discovered generalized Gribov-Lipatov reciprocity holds for the anomalous dimensions of various twist operators in N=4 SYM. Here, we consider a class of scaling psu(2,2|4) operators that reduce at one-loop to twist-3 maximal helicity gluonic operators. We extract from the asymptotic long-range Bethe Ansatz a closed expression for the spin dependen

E. M. Sessolo, D. W. McKay

We calculate low scale gravity effects on the cross section for neutrino-nucleon scattering at center of mass energies up to the Greisen-Zatsepin-Kuzmin (GZK) scale, in the eikonal approximation. We compare the cases of an infinitely thin brane embedded in n=5 compactified extra-dimensions, and of a brane with a physical tension M_{S}=1 TeV and M_{S}=10 TeV.

Jim Bryan, Amin Gholampour

Let G be a polyhedral group, namely a finite subgroup of SO(3). Nakamura&#39;s G-Hilbert scheme provides a preferred Calabi-Yau resolution Y of the polyhedral singularity C^3/G. The classical McKay correspondence describes the classical geometry of Y in terms of the representation theory of G. In this paper we describe the quantum geometry of Y in terms of R

David J. Hemmer

Cohomology of Specht modules for the symmetric group can be equated in low degrees with corresponding cohomology for the Borel subgroup B of the general linear group GL_d(k), but this has never been exploited to prove new symmetric group results. Using work of Doty on the submodule structure of symmetric powers of the natural GL_d(k) module together with wor

Christophe Garban, Gábor Pete, Oded Schramm

Consider the indicator function $f$ of a two-dimensional percolation crossing event. In this paper, the Fourier transform of $f$ is studied and sharp bounds are obtained for its lower tail in several situations. Various applications of these bounds are derived. In particular, we show that the set of exceptional times of dynamical critical site percolation on

Mattias Blennow

We discuss the effects of neutrino mixing and the neutrino mass hierarchy when considering the capture of the cosmic neutrino background (CNB) on radioactive nuclei. The implications of mixing and hierarchy at future generations of tritium decay experiments are considered. We find that the CNB should be detectable at these experiments provided that the resol

Lajos Diósi

I discuss the robustness of the pumped cavity dynamics against phase diffusion of the laser and conclude that opto-mechanical cooling has extreme sensitivity compared to laser cooling of atoms. Certain proposals of ground state opto-mechanical cooling by single cavity would require an unrealistic sharp laser linewidth or equivalently, a very low level of pha

D. Sornette, M. J. Werner

This entry in the Encyclopedia of Complexity and Systems Science, Springer present a summary of some of the concepts and calculational tools that have been developed in attempts to apply statistical physics approaches to seismology. We summarize the leading theoretical physical models of the space-time organization of earthquakes. We present a general discus

Zhi-Wei Sun

We study whether sufficiently large integers can be written in the form cp+T_x, where p is either zero or a prime congruent to r mod d, and T_x=x(x+1)/2 is a triangular number. We also investigate whether there are infinitely many positive integers not of the form (2^ap-r)/m+T_x with p a prime and x an integer. Besides two theorems, the paper also contains s

T. A. Niehaus, R. López, J. F. Rico

Using the shift-operator technique, a compact formula for the Fourier transform of a product of two Slater-type orbitals located on different atomic centers is derived. The result is valid for arbitrary quantum numbers and was found to be numerically stable for a wide range of geometrical parameters and momenta. Details of the implementation are presented to

P. Bourgade

We give a probabilistic proof of the Weyl integration formula on U(n), the unitary group with dimension $n$. This relies on a suitable definition of Haar measures conditioned to the existence of a stable subspace with any given dimension $p$. The developed method leads to the following result: for this conditional measure, writing $Z_U^{(p)}$ for the first n

Ross G. Pinsky

Let $D\subsetneq R^d$ be an unbounded domain and let $B(t)$ be a Brownian motion in $D$ with normal reflection at the boundary. We study the transcience/recurrence dichotomy, focusing mainly on domains of the form $D=\{(x,z)\in R^{l+m}:|z|<H(|x|)\}$, where $d=l+m$ and $H$ is a sufficiently regular function. This class of domains includes various horn-shaped

Christian Brouder, Frédéric Patras

In quantum field theory (QFT), the vacuum expectation value of a normal product of creation and annihilation operators is always zero. This simple property paves the way to the classical treatment of perturbative QFT. This is no longer the case in the presence of initial correlations, that is if the vacuum is replaced by a general state. As a consequence, th

Claude LeBrun

Which smooth compact 4-manifolds admit an Einstein metric with non-negative Einstein constant? A complete answer is provided in the special case of 4-manifolds that also happen to admit either a complex structure or a symplectic structure.

N. Ryzhanova, A. Vedyayev, A. Pertsova, B. Dieny

Quasi-two-dimensional transport is investigated in a system consisting of one ferromagnetic layer placed between two insulating layers. Using the mechanism of skew-scattering to describe the Extraordinary Hall Effect (EHE) and calculating the conductivity tensor, we compare the quasi- two-dimensional Hall resistance with the resistance of a massive sample. I

Michael Stone, Inaki Anduaga, Lei Xing

We explore the classical version of the mapping, due to Abanov and Wiegmann, of Calogero-Sutherland hydrodynamics onto the Benjamin-Ono equation ``on the double.&#39;&#39; We illustrate the mapping by constructing the soliton solutions to the hydrodynamic equations, and show how certain subtleties arise from the need to include corrections to the naive repla

Claude LeBrun

The Einstein-Maxwell equations on a smooth compact 4-manifold are reformulated as a purely Riemannian variational problem analogous to Calabi&#39;s variational problem for extremal Kahler metrics. Next, Seiberg-Witten theory is used to show that these two problems are in fact intimately related. Extremal Kahler metrics are then used to probe the limits of Se

Dajano Tossici

Let R be a discrete valuation ring of unequal characteristic with fraction field K which contains a primitive p^2-th root of unity. Let X be a faithfully flat R-scheme and G be a finite abstract group. Let us consider a G-torsor Y_K\to X_K and let Y be the normalization of X_K in Y. If G=Z/p^n Z, n<3, under some hypothesis on X, we attach some invariants to

B. M. Brown, G. Grubb, I. G. Wood

In this paper, we combine results on extensions of operators with recent results on the relation between the M-function and the spectrum, to examine the spectral behaviour of boundary value problems. M-functions are defined for general closed extensions, and associated with realisations of elliptic operators. In particular, we consider both ODE and PDE examp

Manuel Bähr, Stefan Gieseke, Michael H. Seymour

In this paper we describe a new model of multiple partonic interactions that has been implemented in Herwig++. Tuning its two free parameters we find a good description of CDF underlying event data. We show extrapolations to the LHC.

Christian Stump

We construct a bijection between 231-avoiding permutations and Dyck paths that sends the sum of the major index and the inverse major index of a 231-avoiding permutation to the major index of the corresponding Dyck path. Furthermore, we relate this bijection to others and exhibit a bistatistic on 231-avoiding permutations which is related to the q,t-Catalan

Thorsten Feldmann, Martin Jung, Thomas Mannel

Precision measurements of branching fractions and CP asymmetries in non-leptonic b -> s decays reveal certain &#34;puzzles&#34; when compared with Standard Model expectations based on a global fit of the CKM triangle and general theoretical expectations. Without reference to a particular model, we investigate to what extent the (small) discrepancies observed

Samir D. Mathur

As we follow our Universe to early times, we find that matter was crushed to high densities, somewhat similar to the behavior at a black hole singularity. String theory has made progress in explaining the internal structure of black holes, so we would like to extrapolate the ideas learnt from black holes to the early Universe. If we assume that we want the m

Shuntaro Nakamura, Ken-ichi Okumura, Masahiro Yamaguchi

Although the mirage mediation is one of the most plausible mediation mechanisms of supersymmetry breaking, it suffers from two crucial problems. One is the μ-/B μ-problem and the second is the cosmological one. The former stems from the fact that the B parameter tends to be comparable with the gravitino mass, which is two order of magnitude larger than the o

Michael J. W. Hall

It is shown that a canonical time observable may be defined for any quantum system having a discrete set of energy eigenvalues, thus significantly generalising the known case of time observables for periodic quantum systems (such as the harmonic oscillator). The general case requires the introduction of almost-periodic probability operator measures (POMs), w

Simon Cox, Gennady Mishuris

Simulations of motion by mean curvature in bounded domains, with applications to bubble motion and grain growth, rely upon boundary conditions that are only approximately compatible with the equation of motion. Three closed form solutions for the problem exist, governing translation, rotation and expansion of a single interface [1], providing the only benchm

R. Blossey, C. V. Giuraniuc

We introduce a minimal model description for the dynamics of transcriptional regulatory networks. It is studied within a mean-field approximation, i.e., by deterministic ode&#39;s representing the reaction kinetics, and by stochastic simulations employing the Gillespie algorithm. We elucidate the different results both approaches can deliver, depending on th

I. Alikhanov

We possess convincing experimental evidence for the fact that the real photon has non-trivial parton structure. On the other hand, interactions of the cosmic microwave background photons with high energy particles propagating through the Universe play an important role in astrophysics. In this context, to invoke the parton content could be convenient for cal

Mingyu Xu

In this paper we study different algorithms for reflected backward stochastic differential equations (BSDE in short) with two continuous barriers basing on random work framework. We introduce different numerical algorithms by penalization method and reflected method. At last simulation results are also presented.

Z. Neda, Sz. Horvat, H. M. Tohati, A. Derzsi

A complex two-parameter model resembling the classical voter model is introduced to describe macroecological properties of tropical tree communities. Monte-Carlo type computer simulations are performed on the model, investigating species abundances and the spatial distribution of individuals and species. Simulation results are critically compared with the ex

E. Friedman, A. Gal

Realistic calculations of nuclear disappearance lifetimes induced by neutron-antineutron oscillations are reported for oxygen and iron, using antineutron nuclear potentials derived from a recent comprehensive analysis of antiproton atomic X-ray and radiochemical data. A lower limit of 3.3 x 10E8 s on the neutron-antineutron oscillation time is derived from t

Christoph Wockel

In this paper we introduce principal 2-bundles and show how they are classified by non-abelian Cech cohomology. Moreover, we show that their gauge 2-groups can be described by 2-group-valued functors, much like in classical bundle theory. Using this, we show that, under some mild requirements, these gauge 2-groups possess a natural smooth structure. In the l

Zhongzhi Zhang, Shuigeng Zhou, Lichao Chen, Jihong Guan

Real networks can be classified into two categories: fractal networks and non-fractal networks. Here we introduce a unifying model for the two types of networks. Our model network is governed by a parameter $q$. We obtain the topological properties of the network including the degree distribution, average path length, diameter, fractal dimensions, and betwee

Jorge Mondejar, Antonio Pineda

We obtain the corrections in $1/n$ and in $1/\ln n$ ($n$ is the principal quantum number of the bound state) of the decay constants of scalar and pseudoscalar currents in two and four dimensions in the large $N_c$. We obtain them from the operator product expansion provided a model for the large $n$ mass spectrum is given. In the two-dimensional case the spe

C. J. Papachristou

A number of characteristics of integrable nonlinear partial differential equations (PDE&#39;s) for classical fields are reviewed, such as Backlund transformations, Lax pairs, and infinite sequences of conservation laws. An algebraic approach to the symmetry problem of PDE&#39;s is described, suitable for PDE&#39;s the solutions of which are non-scalar fields

Benjamin Lenk, Gerrit Eilers, Jaroslav Hamrle, Markus Münzenberg

The spin-wave relaxation mechanisms after intense laser excitation in ferromagnetic nickel films are investigated with all-optical pump-probe experiments. Uniform precession (Kittel mode), Damon-Eshbach surface modes and perpendicular standing spin waves can be identified by their dispersion f(H). However, different to other ferromagnets f(H) deviates from t

Massimiliano Rinaldi

We consider the problem of calculating the Green&#39;s functions associated to a massive scalar field with modified dispersion relations. We analyze the case when dispersion is modified by higher derivative spatial operators acting on the field orthogonally to a preferred direction, determined by a unit time-like vector field. By assuming that the integral c

Akimichi Takemura, Vladimir Vovk, Glenn Shafer

We prove game-theoretic generalizations of some well known zero-one laws. Our proofs make the martingales behind the laws explicit, and our results illustrate how martingale arguments can have implications going beyond measure-theoretic probability.

Srikanth B. Iyengar, Tim Roemer

This article concerns linear parts of minimal resolutions of finitely generated modules over commutative local, or graded rings. The focus is on the linearity defect of a module, which marks the point after which the linear part of its minimal resolution is acyclic. The results established track the change in this invariant under some standard operations in

S. Roy, S. Ghosh Deb, C. Sinha

A quantum mechanical approach is proposed for the formation of antihydrogen in the ground and excited states (2s, 2p) via the mechanism of three body recombination (TBR) inside a trapped plasma of anti proton and positron or in the collision between the two beams of them. Variations of the differential (DCS) as well as the total (TCS) formation cross section

Hao Zheng

We categorify the highest weight integrable representations and their tensor products of a symmetric quantum Kac-Moody algebra. As byproducts, we obtain a geometric realization of Lusztig's canonical bases of these representations as well as a new positivity result. The main ingredient in the underlying geometric construction is a class of micro-local perver

Heesang Park, Jongil Park, Dongsoo Shin

As the sequel to [5, 7], we construct a simply connected minimal complex surface of general type with p_g = 0 and K^2 = 4 by using a rational blow-down surgery and Q-Gorenstein smoothing theory.

Litan Yan, Junfeng Liu, Xiangfeng Yang

Let ${\mathscr L}^H(x,t)=2H\int_0^tδ(B^H_s-x)s^{2H-1}ds$ be the weighted local time of fractional Brownian motion $B^H$ with Hurst index $1/2<H<1$. In this paper, we use Young integration to study the integral of determinate functions $\int_{\mathbb R}f(x){\mathscr L}^H(dx,t)$. As an application, we investigate the {\it weighted quadratic covariation} $[f(B^

P. B. Blakie

In this paper we describe a method for evolving the projected Gross-Pitaevskii equation (PGPE) for a Bose gas in a harmonic oscillator potential. The central difficulty in solving this equation is the requirement that the classical field is restricted to a small set of prescribed modes that constitute the low energy classical region of the system. We present