October 2006 arXiv papers — page 43

O. A. Collins, S. D. Jenkins, A. Kuzmich, T. A. B. Kennedy

Long-distance quantum communication via distant pairs of entangled quantum bits (qubits) is the first step towards more secure message transmission and distributed quantum computing. To date, the most promising proposals require quantum repeaters to mitigate the exponential decrease in communication rate due to optical fiber losses. However, these are exquis

Malcolm P. Kennett, Ross H. McKenzie

Many of the most interesting and technologically important electronic materials discovered in the past two decades have two common features: a layered crystal structure and strong interactions between electrons. Two of the most fundamental questions about such layered metals concern the origin of intralayer anisotropies and the coherence of interlayer charge

H. E. Puthoff

In 1953 Casimir proposed a semiclassical model for the electron based on the concept that net inward radiation pressure from the electromagnetic vacuum fluctuations fields (as in the Casimir effect, generally) might play the role of Poincare stresses, compensating outward coulomb pressure to yield a stable configuration at small dimensions. Given that in sca

Yaroslav Tserkovnyak, Bertrand I. Halperin, Alexey A. Kovalev, Arne Brataas

We derive boundary conditions for the coupled spin-charge diffusion equations at a transmitting interface between two-dimensional electron systems with different strengths of the Rashba spin-orbit (SO) coupling $α$, and an electric field parallel to the interface. We consider the limit where the spin-diffusion length l_s is long compared to the electron mean

M. R. Calvo, A. I. Mares, V. Climent, J. M. van Ruitenbeek

Electrochemical methods have recently become an interesting tool for fabricating and characterizing nanostructures at room temperature. Simplicity, low cost and reversibility are some of the advantages of this technique that allows to work at the nanoscale without requiring sophisticated instrumentation. In our experimental setup, we measure the conductance

C. E. DeForest

Fine-scale structure in the corona appears not to be well resolved by current imaging instruments. Assuming this to be true offers a simple geometric explanation for several current puzzles in coronal physics, including: the apparent uniform cross-section of bright threadlike structures in the corona; the low EUV contrast (long apparent scale height) between

Atsushi Yamashita

Let $X, Y$ be separable metrizable spaces, where $X$ is noncompact and $Y$ is equipped with an admissible complete metric $d$. We show that the space $C(X,Y)$ of continuous maps from $X$ into $Y$ equipped with the uniform topology is locally homeomorphic to the Hilbert space of weight $2^{\aleph_0}$ if (1) $(Y, d)$ is an ANRU, a uniform version of ANR and (2

Caterina Guiot, Pier Paolo Delsanto, Thomas S. Deisboeck

We present an analogy between two unrelated instabilities. One is caused by the impact of a drop of water on a solid surface while the other one concerns a tumor that develops invasive cellular branches into the surrounding host tissue. In spite of the apparent abstractness of the idea, it yields a very practical result, i.e. an index that predicts tumor inv

H. Alnes, K. Olaussen, F. Ravndal, I. K. Wehus

The vacuum expectation value of the electromagnetic energy-momentum tensor between two parallel plates in spacetime dimensions D > 4 is calculated in the axial gauge. While the pressure between the plates agrees with the global Casimir force, the energy density is divergent at the plates and not compatible with the total energy which follows from the force.

Miguel Campiglia, Cayetano Di Bartolo, Rodolfo Gambini, Jorge Pullin

We discuss in detail the uniform discretization approach to the quantization of totally constrained theories. This approach allows to construct the continuum theory of interest as a well defined, controlled, limit of well behaved discrete theories. We work out several finite dimensional examples that exhibit behaviors expected to be of importance in the quan

L. Zamick

In a previous work we considered the number of pairs of particles with angular momentum J12 for systems with angular momentum zero.Here we extend the work to states of any total angular momentum.We find simplified relations satisfied for a system of four nucleoons with isospin zero and two.

Stefano Galatolo, Dong Han Kim

We investigate the connection between the dynamical Borel-Cantelli and waiting time results. We prove that if a system has the dynamical Borel-Cantelli property, then the time needed to enter for the first time in a sequence of small balls scales as the inverse of the measure of the balls. Conversely if we know the waiting time behavior of a system we can pr

Emanuele Di Marco

We present recent results on time integrated and time dependent CP violation for charmless hadronic B decays using BABAR detector at the PEP-II B-factory.

E. Boos, V. Bunichev, L. Dudko, M. Perfilov

The paper is devoted to studies of prospects to search for hypothetical W-prime gauge bosons at hadron colliders via single-top quark production process. A special attention is paid to the interference between the Standard Model (SM) W and W-prime} boson contributions. A model independent analysis is performed for a wide interval of W-prime} masses potential

Letizia Stanghellini

Planetary nebulae (PN) represent the evolutionary fate of the asymptotic giant branch (AGB) stellar envelopes, thus are ideally suited to study the chemical impact of AGB stars. Stellar evolution predict elemental enrichment through the AGB evolution, and convective dredge-up episodes allow the products of stellar evolution to reach the stellar outer layers.

E. J. Griffith, C. D. Hill, J. F. Ralph, H. M. Wiseman

We propose techniques for implementing two different rapid state purification schemes, within the constraints present in a superconducting charge qubit system. Both schemes use a continuous measurement of charge (z) measurements, and seek to minimize the time required to purify the conditional state. Our methods are designed to make the purification process

Oliver Brein, Thomas Hahn

We present a calculation of the cross section for the process e+ e- --> W+/- H-/+ in the minimal supersymmetric standard model (MSSM) and the Two Higgs Doublet Model (THDM). We study the basic features of the MSSM prediction for some distinctive parameter scenarios. We find large effects from virtual squarks for scenarios with large mixing in the stop sector

L. A. Bunimovich, C. P. Dettmann

One or more small holes provide non-destructive windows to observe corresponding closed systems, for example by measuring long time escape rates of particles as a function of hole sizes and positions. To leading order the escape rate of chaotic systems is proportional to the hole size and independent of position. Here we give exact formulas for the subsequen

Simone Mercuri

In order to introduce an interaction between gravity and fermions in the Ashtekar-Barbero-Immirzi formalism without affecting classical dynamics a non-minimal term is necessary. The non-minimal term together with the Holst modification to the Hilbert-Palatini action reconstruct the Nieh-Yan invariant. As a consequence the Immirzi parameter, differently from

M. A. Clark, A. D. Kennedy

Improved staggered fermion formulations are a popular choice for lattice QCD calculations. Historically, the algorithm used for such calculations has been the inexact R algorithm, which has systematic errors that only vanish as the square of the integration step-size. We describe how the exact Rational Hybrid Monte Carlo (RHMC) algorithm may be used in this

Marek Korkusinski, Irene Puerto Gimenez, Pawel Hawrylak, Louis Gaudreau

We analyze theoretically and experimentally the electronic structure and charging diagram of three coupled lateral quantum dots filled with electrons. Using the Hubbard model and real-space exact diagonalization techniques we show that the electronic properties of this artificial molecule can be understood using a set of topological Hunds rules. These rules

Hee Jung Kim, Daniel Ruberman

Some generalizations and variations of the Fintushel-Stern rim surgery are known to produce smoothly knotted surfaces. We show that if the fundamental groups of their complements are cyclic, then these surfaces are topologically unknotted. Using a twist-spinning construction from high-dimensional knot theory, we construct examples of knotted surfaces whose c

Vincent Piétu, Anne Dutrey, Stéphane Guilloteau, Edwige Chapillon

We performed sub-arcsecond high-sensitivity nterferometric observations of the thermal dust emission at 1.4 mm and 2.8 mm in the disks surrounding LkCa 15 and MWC 480, with the new 750 m baselines of the IRAM PdBI array. This provides a linear resolution of about 60 AU at the Taurus distance. We report the existence of a cavity of about 50 AU radius in the i

C. D. Westbrook, R. J. Hogan, A. J. Illingworth

A new method of accurately calculating the capacitance of realistic ice particles is described: such values are key to accurate estimates of deposition and evaporation rates in NWP models. The trajectories of diffusing water molecules are directly sampled, using random `walkers'. By counting how many of these trajectories intersect the surface of the ice

Leonardo Angelini, Stefano Boccaletti, Daniele Marinazzo, Mario Pellicoro

We introduce a novel method for identifying the modular structures of a network based on the maximization of an objective function: the ratio association. This cost function arises when the communities detection problem is described in the probabilistic autoencoder frame. An analogy with kernel k-means methods allows to develop an efficient optimization algo

Koji Nuida, Manabu Hagiwara, Hajime Watanabe, Hideki Imai

It is known that Tardos's collusion-secure probabilistic fingerprinting code (Tardos code; STOC'03) has length of theoretically minimal order with respect to the number of colluding users. However, Tardos code uses certain continuous probability distribution in codeword generation, which creates some problems for practical use, in particular, it requires lar

Gerhard C. Hegerfeldt, Jens Timo Neumann, Lawrence S. Schulman

The passage-time distribution for a spread-out quantum particle to traverse a specific region is calculated using a detailed quantum model for the detector involved. That model, developed and investigated in earlier works, is based on the detected particle's enhancement of the coupling between a collection of spins (in a metastable state) and their envir

N. V. Shevchenko, A. Gal, J. Mares

We report on the first genuinely three-body ${\bar K}NN - πΣN$ coupled-channel Faddeev calculation in search for quasi-bound states in the $K^- p p$ system. The main absorptivity in the $K^- p$ subsystem is accounted for by fitting to $K^- p$ data near threshold. Our calculation yields one such quasi-bound state, with $I=1/2$, $J^π=0^-$, bound in the range $

Charles D. Dermer

Our knowledge of the high-energy universe is undergoing a period of rapid change as new astronomical detectors of high-energy radiation start to operate at their design sensitivities. Now is a boomtime for high-energy astrophysics, with new discoveries from Swift and HESS, results from MAGIC and VERITAS starting to be reported, the upcoming launches of the g

A. M. Tsvelik, A. V. Chubukov

We model the Fermi surface of the cuprates by one-dimensional nested parts near $(0,π)$ and $(π,0)$ and unnested parts near the zone diagonals. Fermions in the nested regions form 1D spin liquids, and develop spectral gaps below some $\sim T^*$, but superconducting order is prevented by 1D phase fluctuations. We show that the Josephson coupling between order

Utpal Chattopadhyay, Debottam Das, Partha Konar, D. P. Roy

We investigate the phenomenology of a wino LSP as obtained in AMSB and some string models. The WMAP constraint on the DM relic density implies a wino LSP mass of 2.0-2.3 TeV. We find a viable signature for such a heavy wino at CLIC, operating at its highest CM energy of 5 TeV. One also expects a viable monochromatic $γ$-ray signal from its pair-annihilation

M. Van den Nest, H. J. Briegel

We establish a connection between measurement-based quantum computation and the field of mathematical logic. We show that the computational power of an important class of quantum states called graph states, representing resources for measurement-based quantum computation, is reflected in the expressive power of (classical) formal logic languages defined on t

I. A. Sadovskyy, G. B. Lesovik, G. Blatter

We show that a quantum dot connected via tunnel barriers to superconducting leads traps a continuously tunable and hence fractional charge. The fractional charge on the island is due to particle-hole symmetry breaking and can be tuned via a gate potential acting on the dot or via changes in the phase difference across the island. We determine the groundstate

J. Bleibel, G. Burau, Amand Faessler, C. Fuchs

The implications of parton recombination processes on the dynamics of ultrarelativistic heavy-ion reactions are investigated. To do so, the quark-gluon string transport model has been extended for partonic recombination and fusion processes. Parton recombination leads to short equilibration times and improves significantly on the theoretical description of m

C. Sevik, C. Bulutay

An extensive theoretical study is performed for wide bandgap crystalline oxides and nitrides, namely, SiO_{2}, GeO_{2}, Al_{2}O_{3}, Si_{3}N_{4}, and Ge_{3}N_{4}. Their important polymorphs are considered which are for SiO_{2}: $α$-quartz, $α$- and $β$-cristobalite and stishovite, for GeO_{2}: $α$-quartz, and rutile, for Al_{2}O_{3}: $α$-phase, for Si_{3}N_{

A. Bourgeois, A. A. Aligia, T. Kroll, M. D. Núñez-Regueiro

We construct an effective Hamiltonian for the motion of T2g highly correlated states in NaxCoO2. We solve exactly a multiband model in a CoO6 cluster with electronic occupation corresponding to a nominal Co valence of either +3 or +4. Using the ensuing ground states, we calculate the effective O mediated hopping t=0.10 eV between many-body T2g states, and es

Erik Christensen, Cristina Ivan, Michel L. Lapidus

We construct spectral triples and, in particular, Dirac operators, for the algebra of continuous functions on certain compact metric spaces. The triples are countable sums of triples where each summand is based on a curve in the space. Several fractals, like a finitely summable infinite tree and the Sierpinski gasket, fit naturally within our framework. In t

S. J. Warren, N. C. Hambly, S. Dye, O. Almaini

The First Data Release (DR1) of the UKIRT Infrared Deep Sky Survey (UKIDSS) took place on 2006 July 21. UKIDSS is a set of five large near-infrared surveys, covering a complementary range of areas, depths, and Galactic latitudes. DR1 is the first large release of survey-quality data from UKIDSS and includes 320 sq degs of multicolour data to (Vega) K=18, com

Yuji Kajiyama, Jisuke Kubo, Hiroshi Okada

We consider a non-supersymmetric extension of the standard model with a family symmetry based on D6 Z2 Z2, where one of Z2's is exactly conserved. This Z2 forbids the tree-level neutrino masses and simultaneously ensures the stability of cold dark matter candidates. From the assumption that cold dark matter is fermionic we can single out the D6 singlet r

Erich Graedel, Igor Walukiewicz

We study two-player games of infinite duration that are played on finite or infinite game graphs. A winning strategy for such a game is positional if it only depends on the current position, and not on the history of the play. A game is positionally determined if, from each position, one of the two players has a positional winning strategy. The theory of suc

Erich Graedel, Igor Walukiewicz

We study two-player games of infinite duration that are played on finite or infinite game graphs. A winning strategy for such a game is positional if it only depends on the current position, and not on the history of the play. A game is positionally determined if, from each position, one of the two players has a positional winning strategy. The theory of suc

Andreas Wipf, Thomas Heinzl, Tobias Kaestner, Christian Wozar

We study the Polyakov loop dynamics originating from finite-temperature Yang-Mills theory. The effective actions contain center-symmetric terms involving powers of the Polyakov loop, each with its own coupling. For a subclass with two couplings we perform a detailed analysis of the statistical mechanics involved. To this end we employ a modified mean field a

M. Beccaria, G. Macorini, L. Panizzi, F. M. Renard

We consider the process of associated stop-chargino production in the MSSM at LHC and show that, at the simplest Born level, the production rate is dramatically sensitive to the choice of the benchmark points, oscillating from potentially "visible" maxima of the picobarn size to much smaller, hardly "visible", values. Adopting a canonical cho

J. Haissinski, S. Dagoret, M. Urban, F. Zomer

Birefringence phenomena stemming from vacuum polarization are revisited in the framework of coherent scattering. Based on photon-photon scattering, our analysis brings out the direct connection between this process and vacuum birefringence. We show how this procedure can be extended to the Kerr and the Cotton-Mouton birefringences in vacuum, thus providing a

Hai-Bo Li, Mao-Zhi Yang

$\Dz-\Dzb$ mixing and significant CP violation in the charm system may indicate the signature of new physics. In this study, we suggest that the coherent $\DzDzb$ events from the decay of $Υ(1S) \to \Dz \Dzb$ can be used to measure both mixing parameters and CP violation in charm decays. The neutral $D$ mesons from $Υ(1S)$ decay are strongly boosted, so that

S. Kalyana Rama

We assume that our universe originated from highly excited and interacting strings with coupling constant g_s = {\cal O} (1). Fluctuations of spacetime geometry are large in such strings and the physics dictating the emergence of a final spacetime configuration is not known. We propose that, nevertheless, it is determined by an entropic principle that the fi

Lancelot F. James

This paper develops some general calculus for GGC and Dirichlet process means functionals. It then proceeds via an investigation of positive Linnik random variables, and more generally random variables derived from compositions of a stable subordinator with GGC subordinators, to establish various distributional equivalences between these models and phenomena

Saurya Das, S. Shankaranarayanan

We review aspects of black hole thermodynamics, and show how entanglement of a quantum field between the inside and outside of a horizon can account for the area-proportionality of black hole entropy, provided the field is in its ground state. We show that the result continues to hold for Coherent States and Squeezed States, while for Excited States, the ent

Maurice A. Leutenegger, Stanley P. Owocki, Steven M. Kahn, Frits B. S. Paerels

We fit the Doppler profiles of the He-like triplet complexes of \ion{O}{7} and \ion{N}{6} in the X-ray spectrum of the O star $ζ$ Puppis, using XMM-Newton RGS data collected over $\sim 400$ ks of exposure. We find that they cannot be well fit if the resonance and intercombination lines are constrained to have the same profile shape. However, a significantly

Pavel A. Bolokhov, Maxim Pospelov

We calculate the baryon asymmetry of the Universe resulting from the combination of higher-dimensional Lorentz-noninvariant CPT-odd operators and dimension five operators that induce the majorana mass for neutrinos. The strength of CPT-violating dimension five operators capable of producing the observed value of baryon abundance is directly related to neutri

P. Urquijo

We report a measurement of the inclusive electron energy spectrum for charmed semileptonic decays of B mesons in a 140fb-1 data sample collected at the \Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric energy e+ e- collider. We determine the first four moments of the electron energy spectrum for threshold values of the electron energy bet

Frederick A. Harris

During the last few years there has been a renaissance in charm and charmonium spectroscopy with higher precision measurements at the $ψ^{'}$ and $ψ(3770)$ coming from BESII and CLEOc and many new discoveries coming from B-factories. In this paper, I will review the status of $ψ(3770)$ and below.

R. Paul Butler, John A. Johnson, Geoffrey W. Marcy, Jason T. Wright

We report precise Doppler measurements of GJ849 (M3.5V) that reveal the presence of a planet with a minimum mass of 0.82 Mjup in a 5.16 year orbit. At a = 2.35 AU, GJ849b is the first Doppler-detected planet discovered around an M dwarf to orbit beyond 0.21 AU, and is only the second Jupiter mass planet discovered around a star less massive than 0.5 Msun. Th

Mark P. Davidson

A subjective survey of stochastic models of quantum mechanics is given along with a discussion of some key radiative processes, the clues they offer, and the difficulties they pose for this program. An electromagnetic basis for deriving quantum mechanics is advocated, and various possibilities are considered. It is argued that only non-local or non-causal th

Iara P. de Queiros, W. B. Cardoso, N. G. de Almeida

We solve the problem of the temporal evolution of one of two-modes embedded in a same dissipative environment and investigate the role of the losses after the preparation of a coherent state in only one of the two modes. Based on current cavity QED technology, we present a calculation of the fidelity of a superposition of coherent states engineered in a bimo

Sandu Popescu

A Knill-Laflamme-Milburn (KLM) type quantum computation with bosonic neutral atoms or bosonic ions is suggested. Crucially, as opposite to other quantum computation schemes involving atoms (ions), no controlled interactions between atoms (ions) involving their internal levels are required. Versus photonic KLM computation this scheme has the advantage that si

Antony L Tambyrajah

A theory of quantum dynamics based on a discrete structure underlying the space time manifold is developed for single particles. It is shown that at the micro domain the interaction of particles with the underlying discrete structure results in the quantum space time manifold. Regarding the resulting quantum space-time as perturbation from the Lorentz metric

M. S. Tomas

We consider the van der Waals interaction between two ground-state atoms embedded in adjacent semi-infinite magnetodielectric media, with emphasis on medium effects on it. We demonstrate that, in this case, at small atom-atom distances the van der Waals interaction is screened by the surrounding media in the same way as in an effective (single) medium. At la

Jeremy M. Merritt, Jochen Küpper, Roger E. Miller

Rotationally resolved infrared spectra are reported for the X-HCN (X = Cl, Br, I) binary complexes solvated in helium nanodroplets. These results are directly compared with that obtained previously for the corresponding X-HF complexes [J. M. Merritt, J. Küpper, and R. E. Miller, PCCP, 7, 67 (2005)]. For bromine and iodine atoms complexed with HCN, two linear

Tom G. Mackay, Akhlesh Lakhtakia

Refraction of obliquely incident plane waves due to the interface of a vacuous half-space and a half-space occupied by a simply moving, nondissipative, isotropic dielectric-magnetic medium is considered, when the medium's velocity lies parallel to the interface and in the plane of incidence. Counterposition of the refracted wavevector and time-averaged P

D. Gachet, N. Sandeau, H. Rigneault

We propose a full-vectorial numerical study of far field radiation patterns in coherent anti-Stokes Raman scattering (CARS) microscopy. We emphasis the particular role of the Raman depolarisation ratio of the observed medium and show how it modifies the radiation pattern of thin objects.

N. Sandeau, H. Giovannini

The main advantage of two-photon fluorescence confocal microscopy is the low absorption obtained with live tissues at the wavelengths of operation. However, the resolution of two-photon fluorescence confocal microscopes is lower than in the case of one-photon excitation. The 4Pi microscope type C working in two-photon regime, in which the excitation beams ar

Michel Lintz, Jocelyne Guéna, Marie-Anne Bouchiat

We present the atomic parity violation measurements made in Cs vapour using a pump-probe scheme. After pulsed excitation of the 6S-7S forbidden transition in the presence of a longitudinal electric field, a laser beam resonant with one of the 7S-6P transitions stimulates the 7S atom emission for a duration of 20 ns. The polarisation of the amplified probe be

William Horowitz

We examine the sensitivity and surface bias of convolved DGLV radiative and elastic loss in a realistic geometry including Bjorken expansion. We find that this more faithful treatment of the medium density is not a priori reproducible via fixed length approximations, and neither the fragility nor the surface emission of BDMPS-based models is seen.

V. Yu. Ponomarev, A. I. Vdovin

This is our formal Reply to revised version (v2) of arXiv: nucl-th/0510004v2.

E. Hiyama, Y. Yamamoto, Th. A. Rijken, T. Motoba

Two spin-doublet states of %$3/2^+$-$1/2^+$ and $7/2^+$-$5/2^+$ in $^7_Λ$Li are studied on the basis of the $α+Λ+n+p$ four-body model. We employ the two-body interactions which reproduce the observed properties of any subsystems composed of $αN$, $αΛ$ and $αNN$, and $αΛN$. Furthermore, the $ΛN$ interaction is adjusted so as to reproduce the $0^+$-$1^+$ split

T. X. Liu, W. G. Lynch, M. B. Tsang, X. D. Liu

Collisions of 112Sn and 124Sn nuclei, which differ in their isospin asymmetry, provide information about the rate of isospin diffusion and equilibration. While several different probes can provide accurate diffusion measurements, the ratios of the mirror nuclei may be the simplest and most promising one. Ratios of the mass seven mirror nuclei yields are anal

D. Verney, F. Ibrahim, O. Perru, O. Bajeat

New levels were attributed to $^{81}\_{31}$Ga$\_{50}$ and $^{83}\_{32}$Ge$\_{51}$ which were fed by the $β$-decay of their respective mother nuclei $^{81}\_{30}$Zn$\_{51}$ and $^{83}\_{31}$Ga$\_{52}$ produced by fission at the "PARRNe" ISOL set-up installed at the Tandem accelerator of the Institut de Physique Nucléaire, Orsay. We show that the low e

Fuqiang Wang

Mid-rapidity azimuthal correlations probe di-jets originating mainly from gluon-gluon hard-scattering. Measurements of such correlations have revealed significant (gluon-)jet modification in central Au+Au collisions. Azimuthal correlations at forward rapidity with a mid-rapidity high-pt hadron, on the other hand, are sensitive primarily to quark-gluon hard-s

Javier M. Buldu, M. C. Torrent, Jordi Garcia-Ojalvo

We examine the dynamics of semiconductor lasers coupled in a ring configuration. The lasers, which have stable output intensity when isolated, behave chaotically when coupled unidirectionally in a closed chain. In this way, we show that neither feedback nor bidirectional coupling is necessary to induce chaotic dynamics at the laser output. We study the synch

Luca Degiovanni, Giovanni Rastelli

In this paper the geometric theory of separation of variables for time-independent Hamilton-Jacobi equation is extended to include the case of complex eigenvalues of a Killing tensor on pseudo-Riemannian manifolds. This task is performed without to complexify the manifold but just considering complex-valued functions on it. The simple formalism introduced al

Adrian Constantin, Rossen I. Ivanov, Emil M. Prodanov

We show that the governing equations for two-dimensional gravity water waves with constant non-zero vorticity have a nearly-Hamiltonian structure, which becomes Hamiltonian for steady waves.

José F. Cariñena, Janusz Grabowski, Giuseppe Marmo

A rigorous geometric proof of the Lie's Theorem on nonlinear superposition rules for solutions of non-autonomous ordinary differential equations is given filling in all the gaps present in the existing literature. The proof is based on an alternative but equivalent definition of a superposition rule: it is considered as a foliation with some suitable pro

Michael Baake, Dirk Frettlöh, Uwe Grimm

Pinwheel patterns and their higher dimensional generalisations display continuous circular or spherical symmetries in spite of being perfectly ordered. The same symmetries show up in the corresponding diffraction images. Interestingly, they also arise from amorphous systems, and also from regular crystals when investigated by powder diffraction. We present f

José F. Cariñena, Janusz Grabowski, Giuseppe Marmo

We define quantum bi-Hamiltonian systems, by analogy with the classical case, as derivations in operator algebras which are inner derivations with respect to two compatible associative structures. We find such structures by means of the associative version of Nijenhuis tensors. Explicit examples, e.g. for the harmonic oscillator, are given.

Primitivo Acosta-Humanez, David Blazquez-Sanz

In this work we compute the families of classical Hamiltonians in two degrees of freedom in which the Normal Variational Equation around an invariant plane falls in Schroedinger type with polynomial or trigonometrical potential. We analyze the integrability of Normal Variational Equation in Liouvillian sense using the Kovacic's algorithm. We compute all

Sergi Elizalde, Toufik Mansour

We say that a permutation $π$ is a Motzkin permutation if it avoids 132 and there do not exist $a<b$ such that $π_a<π_b<π_{b+1}$. We study the distribution of several statistics in Motzkin permutations, including the length of the longest increasing and decreasing subsequences and the number of rises and descents. We also enumerate Motzkin permutations with

Sergi Elizalde

A k-triangulation of a convex polygon is a maximal set of diagonals so that no k+1 of them mutually cross in their interiors. We present a bijection between 2-triangulations of a convex n-gon and pairs of non-crossing Dyck paths of length 2(n-4). This solves the problem of finding a bijective proof of a result of Jonsson for the case k=2. We obtain the bijec

Alexander Burstein, Sergi Elizalde, Toufik Mansour

We complete the enumeration of Dumont permutations of the second kind avoiding a pattern of length 4 which is itself a Dumont permutation of the second kind. We also consider some combinatorial statistics on Dumont permutations avoiding certain patterns of length 3 and 4 and give a natural bijection between 3142-avoiding Dumont permutations of the second kin

Sergi Elizalde, Kevin Woods

Directed and undirected graphical models, also called Bayesian networks and Markov random fields, respectively, are important statistical tools in a wide variety of fields, ranging from computational biology to probabilistic artificial intelligence. We give an upper bound on the number of inference functions of any graphical model. This bound is polynomial o

Alan Adolphson, Steven Sperber

We compute a basis for the p-adic Dwork cohomology of a smooth complete intersection in projective space over a finite field and use it to give p-adic estimates for the action of Frobenius on this cohomology. In particular, we prove that the Newton polygon of the characteristic polynomial of Frobenius lies on or above the associated Hodge polygon. This resul

E. Cordero, F. Nicola

We study the dispersive properties of the Schrödinger equation. Precisely, we look for estimates which give a control of the local regularity and decay at infinity {\it separately}. The Banach spaces that allow such a treatment are the Wiener amalgam spaces, and Strichartz-type estimates are proved in this framework. These estimates improve some of the class

Alan Adolphson, Steven Sperber

Let f_1,...,f_r be homogeneous polynomials in K[x_1,...,x_n], K a field. Put F=y_1f_1+...+y_rf_r in K[x,y] and let I be the ideal of K[x,y] generated by the partials of F relative to the x_i and y_j. The Jacobian ring of F is the quotient J:=K[x,y]/I. We describe J by computing the cohomology of a certain complex whose top cohomology group is J.

N. Lanchier, C. Neuhauser

Competition is a major force in structuring ecological communities. The strength of competition can be measured using the concept of a niche. A niche comprises the set of requirements of an organism in terms of habitat, environment and functional role. The more niches overlap, the stronger competition is. The niche breadth is a measure of specialization: the

Michael Megrelishvili

We show that every Hausdorff topological group is a group retract of a minimal topological group. This first was conjectured by Pestov in 1983. Our main result leads to a solution of some problems of Arhangelskii. One of them is the problem about representability of a group as a quotient of a minimal group (Problem 519 in the first edition of &#34;Open Probl

Andreas Cap

This is an expanded version of a series of two lectures given at the IMA summer program &#34;Symmetries and Overdetermined Systems of Partial Differential Equations&#34;. The main part of the article describes the Riemannian version of the prolongation procedure for certain overdetermined system obtained recently in joint work with T.P. Branson, M.G. Eastwoo

Dmitry Kramkov, Mihai S\^{ı}rbu

We study the two-times differentiability of the value functions of the primal and dual optimization problems that appear in the setting of expected utility maximization in incomplete markets. We also study the differentiability of the solutions to these problems with respect to their initial values. We show that the key conditions for the results to hold tru

Luc Molinet, Jean-Claude Saut, Nikolay Tzvetkov

We prove that the Cauchy problem for the KP-I equation is globally well-posed for initial data which are localized perturbations (of arbitrary size) of a non-localized (i.e. not decaying in all directions) traveling wave solution (e.g. the KdV line solitary wave or the Zaitsev solitary waves which are localized in $x$ and $y$ periodic or conversely).

André Mas, Besnik Pumo

We introduce a new model of linear regression for random functional inputs taking into account the first order derivative of the data. We propose an estimation method which comes down to solving a special linear inverse problem. Our procedure tackles the problem through a double and synchronized penalization. An asymptotic expansion of the mean square previs

Kolarič Dejan

Let $K$ be a closed polydisc or ball in $\C^n$, and let $Y$ be a quasi projective algebraic manifold which is Zariski locally equivalent to $\C^p$, or a complement of an algebraic subvariety of codimension $\ge 2$ in such manifold. If $r$ is an integer satisfying $(n-r+1) (p-r+1)\geq 2$ then every holomorphic map from a neighborhood of $K$ to $Y$ with rank $

Thorsten Rheinländer, Gallus Steiger

We determine the minimal entropy martingale measure for a general class of stochastic volatility models where both price process and volatility process contain jump terms which are correlated. This generalizes previous studies which have treated either the geometric Lévy case or continuous price processes with an orthogonal volatility process. We proceed by

Jan Metzger, Felix Schulze

A possible evolution of a compact hypersurface in R^n by mean curvature past singularities is defined via the level set flow. In the case that the initial hypersurface has positive mean curvature, we show that the Brakke flow associated to the level set flow is actually a Brakke flow with equality. We obtain as a consequence that no mass drop can occur along

M. I. Graev, A. M. Vershik

We give a survey of several models of irreducible complementary series representations and their limits, special representations, for the groups SU(n,1) and SO(n,1), including new ones. These groups, whose geometrical meaning is well known, exhaust the list of simple Lie groups for which the identity representation is not isolated in the space of irreducible

Larry Guth

If (M^n, g) is a complete Riemannian manifold with filling radius at least R, then we prove that it contains a ball of radius R and volume at least c(n)R^n. If (M^n, hyp) is a closed hyperbolic manifold and if g is another metric on M with volume at most c(n)Volume(M,hyp), then we prove that the universal cover of (M,g) contains a unit ball with volume great

T. Kappeler, E. Loubet, P. Topalov

We study the exponential maps induced by Sobolev type right-invariant (weak) Riemannian metrics of order $k\ge1$ on the Lie group of smooth, orientation preserving diffeomorphisms of the circle. We prove that each of them defines an {\em analytic} Fréchet chart of the identity.

Michael Malisoff, Frederic Mazenc

We provide explicit closed form expressions for strict Lyapunov functions for time-varying discrete time systems. Our Lyapunov functions are expressed in terms of known nonstrict Lyapunov functions for the dynamics and finite sums of persistency of excitation parameters. This provides a discrete time analog of our previous continuous time Lyapunov function c

M. Eshaghi Gordji, F. Habibian, A. Rejali

The aim of this work is to generalize Johnson&#39;s techniques in order to apply them to establish a bijective correspondence between $S$-derivations and continuous derivations on $M_a(S,ω),$ where $S$ is a locally compact foundation semigroup with identity $e$, and $ω$ is a weight function on $S$, and apply it to find a necessary condition for amenability o

Steven N. Evans

We study the simultaneous zeros of a random family of $d$ polynomials in $d$ variables over the $p$-adic numbers. For a family of natural models, we obtain an explicit constant for the expected number of zeros that lie in the $d$-fold Cartesian product of the $p$-adic integers. Considering models in which the maximum degree that each variable appears is $N$,

Jyh-Haur Teh

We generalize the Harnack-Thom theorem to relate the ranks of the Lawson homology groups with $\Z_2$-coefficients of a real quasiprojective variety with the ranks of its reduced real Lawson homology groups. In the case of zero-cycle group, we recover the classical Harnack-Thom theorem and generalize the classical version to include real quasiprojective varie

Diego Rattaggi

Let $x$, $y$ be two integral quaternions of norm $p$ and $l$, respectively, where $p$, $l$ are distinct odd prime numbers. We investigate the structure of $<x,y>$, the multiplicative group generated by $x$ and $y$. Under a certain condition which excludes $<x,y>$ from being free or abelian, we show for example that $<x,y>$, its center, commutator subgroup an