November 2005 arXiv papers — page 5

Beatrix C. Hiesmayr, Matyas Koniorczyk, Heide Narnhofer

We consider translationally invariant states of an infinite one dimensional chain of qubits or spin-1/2 particles. We maximize the entanglement shared by nearest neighbours via a variational approach based on finitely correlated states. We find an upper bound of nearest neighbour concurrence equal to C=0.434095 which is 0.09% away from the bound C_W=0.434467

Christopher Hardin

Given a universal Horn formula of Kleene algebra with hypotheses of the form r = 0, it is already known that we can efficiently construct an equation which is valid if and only if the Horn formula is valid. This is an example of <i>elimination of hypotheses</i>, which is useful because the equational theory of Kleene algebra is decidable while the universal

Rupa Chatterjee, Evan S. Frodermann, Ulrich W. Heinz, Dinesh K. Srivastava

We predict the transverse momentum (pT) dependence of elliptic flow of thermal photons for Au+Au collisions at the Relativistic Heavy Ion Collider. We model the system hydrodynamically, assuming formation of a thermalized quark-gluon plasma at some early time, followed by cooling through expansion, hadronization and decoupling. Photons are emitted throughout

M. Nowakowski, N. G. Kelkar, T. Mart

Although the neutron (n) does not carry a total electric charge, its charge and magnetization distributions represented in momentum space by the electromagnetic form factors, $F_1^{(n)} (q^2)$ and $F_2^{(n)} (q^2)$, lead to an electromagnetic potential of the neutron. Using this fact, we calculate the electromagnetic corrections to the binding energy, $B_d$,

Pasquale D. Serpico

We discuss the possibility to probe leptonic mixing parameters at high-energy neutrino telescopes in a model-independent way, using astrophysical neutron and pion sources. In particular we show how the octant of the 2-3 mixing angle might be determined independently of prior knowledge of the source, even when current uncertainties on the other mixing paramet

Paolo Merlatti

In type IIB string theory, we consider fractional D3-branes in the orbifold background dual to four-dimensional N=2 supersymmetric Yang-Mills theory. We find the gravitational dual description of the generation of a non-trivial field theory potential on the Coulomb branch. When the orbifold singularity is softened to the smooth Eguchi-Hanson space, the resul

Brian R. Hunt, Eric J. Kostelich, Istvan Szunyogh

Data assimilation is an iterative approach to the problem of estimating the state of a dynamical system using both current and past observations of the system together with a model for the system&#39;s time evolution. Rather than solving the problem from scratch each time new observations become available, one uses the model to ``forecast&#39;&#39; the curre

Giuseppe Bimonte

A new general expression is derived for the fluctuating electromagnetic field outside a metal surface, in terms of its surface impedance. It provides a generalization to real metals of Lifshitz theory of molecular interactions between dielectric solids. The theory is used to compute the radiative heat transfer between two parallel metal surfaces at different

Michael L. Balogh, Arif Babul, G. Mark Voit, Ian G. McCarthy

(Abridged) We revisit the scaling relationships between the dark matter mass and observed X-ray luminosity and temperature of galaxy clusters and groups in the local Universe. Specifically, we compare recent observations with analytic models of the intracluster medium in which the gas entropy distribution has been shifted by a variable amount, K0, to investi

2 Collaboration, C. Lazzeroni, D. J. Munday, M. W. Slater

We report the results from a study of ~23 Million K+- ==> pi+- pizero pizero decays recorded by the NA48/2 experiment at the CERN SPS, showing an anomaly in the pizero pizero invariant mass distribution in the region around 2m+, where m+ is the charged pion mass. This anomaly, never observed in previous experiments, can be interpreted as an effect due mainly

Julien Lesgourgues, Laurence Perotto, Sergio Pastor, Michel Piat

We evaluate the ability of future cosmic microwave background (CMB) experiments to measure the power spectrum of large scale structure using quadratic estimators of the weak lensing deflection field. We calculate the sensitivity of upcoming CMB experiments such as BICEP, QUaD, BRAIN, ClOVER and PLANCK to the non-zero total neutrino mass M_nu indicated by cur

Jonathan Oppenheim, Robert W. Spekkens, Andreas Winter

Recently, it was discovered that the `quantum partial information&#39; needed to merge one party&#39;s state with another party&#39;s state is given by the conditional entropy, which can be negative [Horodecki, Oppenheim, and Winter, Nature 436, 673 (2005)]. Here we find a classical analogue of this, based on a long known relationship between entanglement an

M. Harada, C. Sasaki

We study the chiral symmetry restoration using the generalized hidden local symmetry (GHLS) which incorporates the rho and A_1 mesons as the gauge bosons of the GHLS and the pion as the Nambu-Goldstone boson consistently with the chiral symmetry of QCD. We show that a set of parameter relations, which ensures the first and second Weinberg&#39;s sum rules, is

Ashish Khisti, Uri Erez, Amos Lapidoth, Gregory Wornell

A generalization of the problem of writing on dirty paper is considered in which one transmitter sends a common message to multiple receivers. Each receiver experiences on its link an additive interference (in addition to the additive noise), which is known noncausally to the transmitter but not to any of the receivers. Applications range from wireless multi

C. Adler

We present measurements of position and angular resolution of drift chambers operated with a Xe,CO$_2$(15%) mixture. The results are compared to Monte Carlo simulations and important systematic effects, in particular the dispersive nature of the absorption of transition radiation and non-linearities, are discussed. The measurements were carried out with prot

Alexander Studenikin

Motivated by the need of elaboration of the quantum theory of the spin light of neutrino in matter ($SL\nu$), we have studied in more detail the exact solutions of the Dirac equation for neutrinos moving in the background matter. These exact neutrino wavefunctions form a basis for a rather powerful method of investigation of different neutrino processes in m

William Komp

In this paper, we consider a couple of alternative dark energy models using the total equation of state of the cosmological fluid, $\wt$. These models are fit to the recent type-Ia supernovae data and are compared to previously considered models. The first model is based on the hyperbolic tangent and provides a good estimate of the rate of the transition to

A. Andronic

We present measurements of the spectral distribution of transition radiation generated by electrons of momentum 1 to 10 GeV/c in different radiator types. We investigate periodic foil radiators and irregular foam and fiber materials. The transition radiation photons are detected by prototypes of the drift chambers to be used in the Transition Radiation Detec

Urs Hartl

We develop the analog in equal positive characteristic of Fontaine&#39;s theory for crystalline Galois representations of a p-adic field. In particular we describe the analog of Fontaine&#39;s functor which assigns to a crystalline Galois representation an isocrystal with a Hodge filtration. In equal characteristic the role of isocrystals and Hodge filtratio

C. Romeike, M. R. Wegewijs, W. Hofstetter, H. Schoeller

We consider transport through a single-molecule magnet strongly coupled to metallic electrodes. We demonstrate that for half-integer spin of the molecule electron- and spin-tunneling \emph{cooperate} to produce both quantum tunneling of the magnetic moment and a Kondo effect in the linear conductance. The Kondo temperature depends sensitively on the ratio of

Barak Bringoltz

We study the critical behavior at nonzero temperature phase transitions of an effective Hamiltonian derived from lattice QCD in the strong-coupling expansion. Following studies of related quantum spin systems that have a similar Hamiltonian, we show that for large $N_c$ and fixed $g^2N_c$, mean field scaling is not expected, and that the critical region has

Andrei Linde, Viatcheslav Mukhanov

We discuss nontrivial features of the large scale structure of the universe in the simplest curvaton model proposed in our paper astro-ph/9610219. The amplitude of metric perturbations in this model takes different values in different parts of the universe. The spatial distribution of the amplitude looks like a web consisting of exponentially large cells. De

Ivan Soprunov

We consider families of sparse Laurent polynomials f_1,...,f_n with a finite set of common zeroes Z_f in the complex algebraic n-torus. The global residue assigns to every Laurent polynomial g the sum of its Grothendieck residues over the set Z_f. We present a new symbolic algorithm for computing the global residue as a rational function of the coefficients

F. Fazileh, X. Chen, R. J. Gooding, K. V. Tabunshchyk

We have examined the behaviour of noninteracting electrons moving on a corner-sharing tetrahedral lattice into which we introduce a uniform (box) distribution, of width W, of random on-site energies. We have used both the relative localization length and the spectral rigidity to analyze the nature of the eigenstates, and have determined both the mobility edg

U. Bach, T. P. Krichbaum, A. Kraus, A. Witzel

To determine the location of the intra-day variable (IDV) emission region within the jet of the BL Lac object S5 0716+714, a multi-epoch VSOP polarization experiment was performed in Autumn 2000. To detect, image, and monitor the short term variability of the source, three space-VLBI experiments were performed with VSOP at 5 GHz, separated in time by six day

J. I. Read, M. I. Wilkinson, N. Wyn Evans, G. Gilmore

There are two main tidal effects which can act on the Local Group dwarf spheroidals (dSphs): tidal stripping and tidal shocking. Using N-body simulations, we show that tidal stripping always leads to flat or rising projected velocity dispersions beyond a critical radius; it is $\sim 5$ times more likely, when averaging over all possible projection angles, th

Armen Sedrakian, John W. Clark

We study the finite temperature-density phase diagram of an attractive fermionic system that supports two-body (dimer) and three-body (trimer) bound states in free space. Using interactions characteristic for nuclear systems, we obtain the critical temperature T_c2 for the superfluid phase transition and the limiting temperature T_c3 for the extinction of tr

David Burns, Otmar Venjakob

We discuss the formalism of Iwasawa theory descent in the setting of the localized K_1-groups of Fukaya and Kato. We then prove interpolation formulas for the `leading terms&#39; of the global Zeta isomorphisms that are associated to certain Tate motives and of the p-adic L-functions that are associated to certain critical motives.

P. L. Dufton, R. S. I. Ryans, S. Simon-Diaz, C. Trundle

High-resolution spectra for 24 SMC and Galactic B-type supergiants have been analysed to estimate the contributions of both macroturbulence and rotation to the broadening of their metal lines. Two different methodologies are considered, viz. goodness-of-fit comparisons between observed and theoretical line profiles and identifying zeros in the Fourier transf

M. Ridderstad, M. Juvela, K. Lehtinen, D. Lemke

We have analyzed the properties of dust in the high galactic latitude translucent cloud Lynds 1780 using ISOPHOT maps at 100 and 200 micrometers and raster scans at 60, 80, 100, 120, 150 and 200 micrometers. In far-infrared (FIR) emission, the cloud has a single core that coincides with the maxima of visual extinction and 200um optical depth. At the resoluti

Piotr Kosinski, Magdalena Zych

An elementary proof is given of the bound on &#34;ortogonalization time&#34;.

Ganna Kudryavtseva

It is proved that the automorphism group of a semigroup being an inflation of its proper subsemigroup decomposes into a semidirect product of two groups one of which is a direct sum of full symmetric groups.

Guo-Ping Guo, Hui Zhang, Guang-Can Guo

By exploiting the fermionic qubit parity measurement, we present a scheme to realize quantum non-demolition (QND) measurement of Bell-states and generate n-party GHZ state in quantum dot. Compared with the original protocol, the required electron transfer before and after parity measurement can be nonadiabatic, which may speed up the operation speed and make

Soon-Tae Hong, Joohan Lee, Tae Hoon Lee, Phillial Oh

We solve the quantum mechanical problem of a charged particle on S^2 in the background of a magnetic monopole for both bosonic and supersymmetric cases by constructing Hilbert space and realizing the fundamental operators obeying complicated Dirac bracket relations in terms of differential operators. We find the complete energy eigenfunctions. Using the lowe

S. Ando, R. H. Cyburt, S. W. Hong, C. H. Hyun

The total cross section for radiative neutron capture on a proton, $np \to d γ$, is evaluated at big bang nucleosynthesis (BBN) energies. The electromagnetic transition amplitudes are calculated up to next-to leading order within the framework of pionless effective field theory with dibaryon fields. We also calculate the $dγ\to np$ cross section and the phot

S Datta

We investigate the thermodynamic properties of a trappoed Bose gas of Rb atoms interacting through a repulsive potential by Quantum Monte Carlo method based upon the generalization of Feynman-Kac method[1] applicable to many body systems at T=0 to finite temperatures. In this letter,we report the temperature variation of condensation fraction, chemical poten

Hock-Seng Goh, Siew-Phang Ng, Nobuchika Okada

We explore the possibility of gauge mediation in a paradigm whereby supersymmetry is posited to be an accidental symmetry of Nature and the Standard Model fields are composite bound states that emerge from a conformal field theory. The resultant effective theory can, through sequestering and conformal dynamics, exhibit most of the properties of low energy su

H. Adachi, P. Miranović, M. Ichioka, K. Machida

We study the basal-plane anisotropies of reversible magnetization and torque in a mixed state of layered d-wave superconductors based on the quasiclassical version of the BCS-Gor&#39;kov theory. Both the longitudinal magnetization ($M_L$) and torque ($τ$) show fourfold oscillations as a function of the field angle $χ$. The relationship between the node posit

Y. C. Ma, N. L. Wang

We present in-plane optical study on Tl$_{2}$Ba$_{2}$CuO$_{6+δ}$ single crystals with substantially different $T_c$. The study reveals that the overdoping does not lead to a further increase of the carrier density but a decrease of scattering rate. The most significant change occurs at low temperature and in the low frequency. A characteristic spectral featu

R. Muradian, Diego Frias

This is an exposition of some basic mathematical aspects of quantum logic gates. At first we established some general formulas for the case of arbitrary quantum gate A with unique restriction A^2=I. The explicit form of the generators and roots of matrix A have been found . Then we apply general results to the particular cases of one-qubit and multi-qubit qu

Bing Chen, Z. Song, C. P. Sun

As a demonstration of the spectrum-parity matching condition (SPMC) for quantum state transfer, we investigate the propagation of single-magnon state in the Heisenberg chain in the confined external tangent magnetic field analytically and numerically. It shows that the initial Gaussian wave packet can be retrieved at the counterpart location near-perfectly o

Dariusz Chruscinski, Andrzej Kossakowski

Using well known duality between quantum maps and states of composite systems we introduce the notion of Schmidt number of a quantum channel. It enables one to define classes of quantum channels which partially break quantum entanglement. These classes generalize the well known class of entanglement breaking channels.

Shi-Jian Gu, Guang-Shan Tian, Hai-Qing Lin

We examine several well known quantum spin models and categorize behavior of pairwise entanglement at quantum phase transitions. A unified picture on the connection between the entanglement and quantum phase transition is given.

Sang Pyo Kim

We introduce a novel method to find exact density operators for a spin-1/2 particle in time-dependent magnetic fields by using the one-mode bosonic representation of $su(2)$ and the connection with a time-dependent oscillator. As illustrative examples, we apply the method to find the density operators for constant and/or oscillating magnetic fields, which tu

Joe Henson

The principle of common cause is discussed as a possible fundamental principle of physics. Some revisions of Reichenbach&#39;s formulation of the principle are given, which lead to a version given by Bell. Various similar forms are compared and some equivalence results proved. The further problems of causality in a quantal system, and indeterministic causal

Ala Trusina, Kim Sneppen, Ian B. Dodd, Keith E. Shearwin

The relationship between the design and functionality of molecular networks is now a key issue in biology. Comparison of regulatory networks performing similar tasks can give insights into how network architecture is constrained by the functions it directs. We here discuss methods of network comparison based on network architecture and signaling logic. Intro

David R. B. Stockwell

WhyWhere is a new ecological niche modeling (ENM) algorithm for mapping and explaining the distribution of species. The algorithm uses image processing methods to efficiently sift through large amounts of data to find the few variables that best predict species occurrence. The purpose of this paper is to describe and justify the main parameterizations and to

David R. B. Stockwell, James H. Beach, Aimee Stewart, Gregory Vorontsov

Lifemapper (http://www.lifemapper.org) is a predictive electronic atlas of the Earth&#39;s biological biodiversity. Using a screensaver version of the GARP genetic algorithm for modeling species distributions, Lifemapper harnesses vast computing resources through &#39;volunteers&#39; PCs similar to SETI@home, to develop models of the distribution of the worl

Anders Eriksson, Olof Görnerup, Martin Nilsson Jacobi, Steen Rasmussen

At an early stage in pre-biotic evolution, groups of replicating molecules must coordinate their reproduction to form aggregated units of selection. Mechanisms that enable this to occur are currently not well understood. In this paper we introduce a deterministic model of primitive replicating aggregates, proto-organisms, that host populations of replicating

Alexander K. Motovilov

We discuss the structure of the two- and three-body T-matrices, scattering matrices, and resolvents continued to the unphysical energy sheets. Our conclusions arise due to the representations that have been found for analytically continued momentum-space kernels of the T-operators. These representations are explicitly written only in terms of the physical-sh

Chung-I Chou, Sai-Ping Li

The Political Districting Problem is mapped to a $q$-state Potts model in which the constraints can be written as interactions between sites or external fields acting on the system. Districting into $q$ voter districts is equivalent to finding the ground state of this $q$-state Potts model. We illustrate this by districting Taipei city in its 2008 Legislatur

E. L. Saldin, E. A. Schneidmiller, M. V. Yurkov

Since spring, 2005 vacuum ultraviolet free electron laser (VUV FEL) at DESY operates as user facility in the wavelength range around 30 nm. Electron beam formation system at the VUV FEL is essentially nonlinear and naturally results in a formation of a short high-current leading peak in the density distribution that produces FEL radiation. The main feature o

Andrea Scharnhorst, Werner Ebeling

The acquisition of competence is a key element in the ability to assert oneself in the complex and rapidly changing modern worlds of work. This paper examines the evolution of competence, i.e. the role of competences in an evolutionary problem-solving process, and the role of flexibility as a meta-competence from the perspective of the general concept of Geo

Francois Henault

This paper deals with the theoretical principle and optical design of a phase-shifting telescope-interferometer. What is called a &#34;Telescope-Interferometer&#34; (T-I) is indeed a novel, recently proposed Wavefront Error (WFE) sensing technique, whose basic idea consists in combining the main pupil of a telescope with a second, off-axis reference arm. The

L. Lacaze, P. Le Gal, S. Le Dizès

A theoretical and experimental study of the spin-over mode induced by the elliptical instability of a flow contained in a slightly deformed rotating spherical shell is presented. This geometrical configuration mimics the liquid rotating cores of planets when deformed by tides coming from neighboring gravitational bodies. Theoretical estimations for the growt

Giampiero Esposito

In this expository article we describe the attempt of defining cosmological singularities and we discuss their meaning in classical and quantum cosmology.

Christian R. Rosberg, Ivan L. Garanovich, Andrey A. Sukhorukov, Dragomir N. Neshev

We demonstrate experimentally all-optical beam steering in modulated photonic lattices induced optically by three beam interference in a biased photorefractive crystal. We identify and characterize the key physical parameters governing the beam steering, and show that the spatial resolution can be enhanced by the additional effect of nonlinear beam self-loca

P. Le Gal, L. Lacaze, S. Le Dizès

It is usually believed that the geo-dynamo of the Earth or more generally of other planets, is created by the convective fluid motions inside their molten cores. An alternative to this thermal or compositional convection can however be found in the inertial waves resonances generated by the eventual precession of these planets or by the possible tidal distor

Francesco Guerra, Nadia Robotti

Ettore Majorana proposed an important improvement to the Thomas-Fermi statistical model for atoms, with a communication at the general meeting of the Italian Physical Society, held in Rome, on December 29th, 1928, regularly published on Nuovo Cimento. This communication did not receive any mention, neither in the numerous publications of Fermi and his associ

Geetha Gopakumar, Chiranjib Sur, Bhanu Pratap Das, Rajat K. Chaudhuri

The connections between the Random Phase Approximation (RPA) and Many-Body Perturbation Theory (MBPT) and its all order generalisation, the Coupled- Cluster Theory (CCT) have been explored. Explicit expressions have been derived for the electric dipole amplitudes for allowed and forbidden transitions induced by the parity non-conserving neutral weak interact

O. G. Grebenyuk

The vector and tensor analyzing powers as well as the polarization of the outgoing proton are calculated for the exclusive deuteron break-up reaction $\vec{d}p \to \vec{p}pn$ at a deuteron beam energy of 2 GeV. Two component covariant formalism of Stapp has been used to have the completely Lorentz invariant model. In addition to the Impulse Approximation the

T. Frederico, M. T. Yamashita, A. Delfino, Lauro Tomio

The classification of large halos formed by two identical particles and a core is systematically addressed according to interparticle distances. The root-mean-square distances between the constituents are described by universal scaling functions obtained from a renormalized zero-range model. Applications for halo nuclei, $^{11}$Li and $^{14}$Be, and for atom

R. Tamagaki, T. Takatsuka

We study baryonic superfluidity under the combined pion condensation with delta-mixing, where both condensates of the neutral and charged pions take place in neutron stars. Outline of formulation treating such superfluidity is presented and energy gap calculations show the possibility that critical temperatures are higher than about 1x10^9 K.

Nir Barnea, Winfried Leidemann, Giuseppina Orlandini, Victor D. Efros

Using the Lorentz Integral Transform (LIT) method we compare the results for the triton total photodisintegration cross section obtained using the Correlated Hyperspherical Harmonics (CHH) and the Effective Interaction Hyperspherical Harmonics (EIHH) techniques. We show that these two approaches, while rather different both conceptually and computationally,

I. Barabanov, S. Belogurov, L. Bezrukov, A. Denisov

Production of $^{60}$Co and $^{68}$Ge from stable isotopes of Germanium by nuclear active component of cosmic rays is a principal background source for a new generation of $^{76}$Ge double beta decay experiments like GERDA and Majorana. The biggest amount of cosmogenic activity is expected to be produced during transportation of either enriched material or a

Michael McCumber, Justin Frantz

As in previous analyses at sqrt(s_NN) 200 GeV, correlations in azimuthal angles between inclusive charge particles at intermediate transverse momentum (p_T = 1.0-4.0) GeV/c are studied at sqrt(s_NN) 62.4 GeV. The jet correlations reveal similar modification as in 200 GeV. Specifically large modification, including the &#34;volcano&#34; or &#34;cone&#34; stru

L. Qiao, I. G. Kevrekidis, C. Punckt, H. H. Rotermund

We explore the effect of boundary curvature on the instability of reactive pulses in the catalytic oxidation of CO on microdesigned Pt catalysts. Using ring-shaped domains of various radii, we find that the pulses disappear (decollate from the inert boundary) at a turning point bifurcation, and trace this boundary in both physical and geometrical parameter s

Maciej Blaszak, Krzysztof Marciniak

We propose a general scheme of constructing of soliton hierarchies from finite dimensional Stäckel systems and related separation relations. In particular, we concentrate on the simplest class of separation relations, called Benenti class, i.e. certain Stäckel systems with quadratic in momenta integrals of motion.

J. R. Sanchez, R. Lopez-Ruiz

The searching for the stable patterns in the evolution of cellular automata is implemented using stochastic synchronization between the present structures of the system and its precedent configurations. For most of the known evolution rules with complex behavior a dynamic competition among all the possible stable patterns is established and no stationary reg

György Steinbrecher, Boris Weyssow

The stability against perturbations of a dynamical system conserving a generalized phase-space volume is studied by exploiting the similarity between statistical physics formalism and that of ergodic theory. A general continuity theorem is proved. Resulting from this theorem the double average - time and ensemble - of an observable of a weakly perturbed ergo

Jacek Gilewicz, Elie Leopold, Andreas Ruffing, Galliano Valent

The orthogonal polynomials with recurrence relation \[(\la\_n+μ\_n-z) F\_n(z)=μ\_{n+1} F\_{n+1}(z)+\la\_{n-1} F\_{n-1}(z)\] with two kinds of cubic transition rates $\la\_n$ and $μ\_n,$ corresponding to indeterminate Stieltjes moment problems, are analyzed. We derive generating functions for these two classes of polynomials, which enable us to compute their

Olga Rozanova

The question on expansion of moving volume inside of a smooth flow of the compressible liquid is under consideration. We find a condition on initial data such that if it holds, then within a finite time either the boundary of the moving volume attains a given neighborhood of a certain point (that do not belong to the volume initially), or some a priori estim

Katerina Ozanova

We discuss magnetic Schrodinger operators perturbed by measures from the generalized Kato class. Using an explicit Krein-like formula for their resolvent, we prove that these operators can be approximated in the strong resolvent sense by magnetic Schrodinger operators with point potentials. Since the spectral problem of the latter operators is solvable, one

L. Stodolsky

The study of the number of photons leads to a new way of characterizing curves and to a novel integral invariant over curves.

Peter Kuchment, Boris Vainberg

The article is devoted to the following question. Consider a periodic self-adjoint difference (differential) operator on a graph (quantum graph) G with a co-compact free action of the integer lattice Z^n. It is known that a local perturbation of the operator might embed an eigenvalue into the continuous spectrum (a feature uncommon for periodic elliptic oper

Leslie Ann Goldberg, Markus Jalsenius, Russell Martin, Mike Paterson

We consider the anti-ferromagnetic Potts model on the the integer lattice Z^2. The model has two parameters, q, the number of spins, and λ=\exp(-β), where βis ``inverse temperature&#39;&#39;. It is known that the model has strong spatial mixing if q>7 or if q=7 and λ=0 or λ> 1/8 or if q=6 and λ=0 or λ> 1/4. The lambda=0 case corresponds to the model in which

Mark Elin

In this note we obtain some distortion results for spirallike functions with respect to a boundary point. In particular, we find the maximal domain covered by all spirallike functions of order $β$.

Daniel K. Biss, Daniel Dugger, Daniel C. Isaksen

Cayley-Dickson algebras are an infinite sequence of non-associative algebras starting with the reals, complexes, quaternions, and octonions. We study the zero-divisors in the higher Cayley-Dickson algebras. In particular, we show that the annihilator of any element in the 2^n-dimensional Cayley-Dickson algebra has dimension at most 2^n-4n+4. Moroever, every

Pierpaolo Esposito, Nassif Ghoussoub, Yujin Guo

We study the branch of semi-stable and unstable solutions (i.e., those whose Morse index is at most one) of the Dirichlet boundary value problem $-Δu=\frac{λf(x)}{(1-u)^2}$ on a bounded domain $Ω\subset \R^N$, which models --among other things-- a simple electrostatic Micro-Electromechanical System (MEMS) device. We extend the results of [11] relating to the

N. Bergeron

We give a new proof of a Theorem of Vogan which classify the cohomological representations of a real semisimple Lie group $G$ which are isolated in the unitary dual of $G$. We investigate the same question in the automorphic dual, and obtain partial results. We derive applications of all this results (or conjectures) to the study of the cohomology of arithme

V. M. Gichev

Let $\De u+\la u=\De v+\la v=0$, where $\De$ is the Laplace--Beltrami operator on a compact connected smooth manifold $M$ and $\la>0$. If $H^1(M)=0$ then there exists $p\in M$ such that $u(p)=v(p)=0$. For homogeneous $M$, $H^1(M)\neq0$ implies the existence of a pair $u,v$ as above that has no common zero.

Stephane Genieys, Vitaly Volpert, Pierre Auger

We study a reaction-diffusion equation with an integral term describing nonlocal consumption of resources. We show that a homogeneous equilibrium can lose its stability resulting in appearance of stationary spatial structures. It is a new mechanism of pattern formation in population dynamics that can explain emergence of biological species due to intra-speci

Hatem Mejjaoli

In this paper we define and study the Dunkl convolution product and the Dunkl transform on spaces of distributions on $ \mathbb{R}^d$. By using the main results obtained, we study the hypoelliptic Dunkl convolution equations in the space of distributions.

Barbara McGillivray

In this paper we study the higher secant varieties of Grassmann varieties in relation to Waring&#39;s problem for alternating tensors and to Alexander-Hirschowitz theorem. We show how to identify defective higher secant varieties of Grassmannians using a probabilistic method involving Terracini&#39;s Lemma, and we describe an algorithm which can compute, by

Boris Adamczewski, Yann Bugeaud, Les J. L. Davison

It is widely believed that the continued fraction expansion of every irrational algebraic number $α$ either is eventually periodic (and we know that this is the case if and only if $α$ is a quadratic irrational), or it contains arbitrarily large partial quotients. Apparently, this question was first considered by Khintchine. A preliminary step towards its re

Boris Adamczewski, Yann Bugeaud

We use the Schmidt Subspace Theorem to establish the transcendence of a class of quasi-periodic continued fractions. This improves earlier works of Maillet and of A. Baker. We also improve an old result of Davenport and Roth on the rate of increase of the denominators of the convergents to any real algebraic number.

Boris Adamczewski, Yann Bugeaud

Let $\k$ be an arbitrary field. For any fixed badly approximable power series $Θ$ in $\k((X^{-1}))$, we give an explicit construction of continuum many badly approximable power series $Φ$ for which the pair $(Θ, Φ)$ satisfies the Littlewood conjecture. We further discuss the Littlewood conjecture for pairs of algebraic power series.

Frederic A. B. Edoukou

We study the functional codes $C_2(X)$ defined on projective varieties $X$, in the case where $X\subset \mathbb{P}^3$ is a 1-degenerate quadric or a non-degenerate quadric (hyperbolic or elliptic). We find the minimum distance of these codes, the second weight, and the third weight. We also show the geometrical structure of the first weight and second weight

Boris Adamczewski, Yann Bugeaud

For any given real number $α$ with bounded partial quotients, we construct explicitly continuum many real numbers $β$ with bounded partial quotients for which the pair $(α, β)$ satisfies a strong form of the Littlewood conjecture. Our proof is elementary and rests on the basic theory of continued fractions.

Boris Adamczewski, Yann Bugeaud

The continued fraction expansion of an irrational number $α$ is eventually periodic if and only if $α$ is a quadratic irrationality. However, very little is known regarding the size of the partial quotients of algebraic real numbers of degree at least three. Because of some numerical evidence and a belief that these numbers behave like most numbers in this r

Boris Adamczewski, Yann Bugeaud

Let $b \ge 2$ be an integer. We prove that the $b$-adic expansion of every irrational algebraic number cannot have low complexity. Furthermore, we establish that irrational morphic numbers are transcendental, for a wide class of morphisms. In particular, irrational automatic numbers are transcendental. Our main tool is a new, combinatorial transcendence crit

Ivan Cheltsov, Jihun Park

We prove that for n= 5, 6, 7, a nodal hypersurface of degree n in P^4 is factorial if it has at most (n-1)^2-1 nodes.

Mirel Sorin Stoian

In this paper we present some spectral property for quotient bounded operators and locally bounded operators on locally convex spaces. We introduce the spectral radius of a quotient bounded operator and we show that the Gelfand formula for spectral radius and Newmann series have the same properties like in Banach spaces. Moreover, the geometrical radius of t

Claudio Arezzo, Alessandro Ghigi, Andrea Loi

In this paper we study the first eigenvalue of the Laplacian on a compact Kaehler manifold using stable bundles and balanced bases.

W. A. de Graaf

First we describe the Skjelbred-Sund method for classifying nilpotent Lie algebras. Then we use it to classify 6-dimensional nilpotent Lie algebras over any field of characteristic not 2. The proof of this classification is essentially constructive: for a given 6-dimensional nilpotent Lie algebra L, following the steps of the proof, it is possible to find a

Alireza Abdollahi, Aliakbar Mohammadi Hassanabadi

Let $n>0$ be an integer and $\mathcal{X}$ be a class of groups. We say that a group $G$ satisfies the condition $(\mathcal{X},n)$ whenever in every subset with $n+1$ elements of $G$ there exist distinct elements $x,y$ such that $<x,y>$ is in $\mathcal{X}$. Let $\mathcal{N}$ and $ \mathcal{A}$ be the classes of nilpotent groups and abelian groups, respectivel

D. Kaledin

We introduce a version of the Cartier isomorphism for de Rham cohomology valid for associative, not necessarily commutative algebras over a field of positive characteristic. Using this, we imitate the well-known argument of P. Deligne and L. Iluusie and prove, in some cases, a conjecture of M. Kontsevich which claims that the Hodge-to-de Rham, a.k.a. Hochsch

Prakash Belkale

We give a geometric proof of a conjecture of W. Fulton on the multiplicities of irreducible representations in a tensor product of irreducible representations for GL(r).

Michael A. Hill

In this paper, we introduce a Hopf algebra, developed by the author and Andre Henriques, which is usable in the computation of the tmf homology of a space. As an application, we compute the tmf homology of BSigma_3 in a manner analogous to Mahowald&#39;s computation of the ko homology RP^infty.

G. Giacomin, F. L. Toninelli

We consider general disordered models of pinning of directed polymers on a defect line. This class contains in particular the $(1+1)$--dimensional interface wetting model, the disordered Poland--Scheraga model of DNA denaturation and other $(1+d)$--dimensional polymers in interaction with flat interfaces. We consider also the case of copolymers with adsorpti