March 2006 arXiv papers — page 41

Ko Nakamura, Toshikazu Shigeyama

We find self-similar solutions to describe the interaction of spherically symmetric ejecta expanding at relativistic speeds with an ambient medium having a power law density distribution. Using this solution, the time evolution of the Lorentz factor of the outer shock is derived as a function of the explosion energy, the mass of the ejecta, and parameters fo

Yong-Seon Song

The large scale structure formation in the standard Einstein gravity at later time is uniquely determined by the expansion history H(z) measured by the geometrical factor. A possible departure from the expected standard structure formation is detectable by growth structure test. We design new deviation parameters to test standard gravity at large scales and

A. Yu. Pirkovskii

We characterize projective and injective Banach modules in approximate terms, generalizing thereby a characterization of contractible Banach algebras given by F. Ghahramani and R. J. Loy. As a corollary, we show that each uniformly approximately amenable Banach algebra is amenable. Some applications to homological dimensions of Banach modules and algebras ar

Marco Peloso, Lorenzo Sorbo, Gianmassimo Tasinato

We consider a six dimensional space-time, in which two of the dimensions are compactified by a flux. Matter can be localized on a codimension one brane coupled to the bulk gauge field and wrapped around an axis of symmetry of the internal space. By studying the linear perturbations around this background, we show that the gravitational interaction between so

Saugata Ghosh

We obtain generalized Christoffel-Darboux (GCD) formula for skew-orthogonal polynomials (SOP). Using this, we present an alternative derivation of the level density and two-point function for Gaussian orthogonal ensembles (GOE) and Gaussian symplectic ensembles (GSE) of random matrices.

Davide Sarchi, Vincenzo Savona

We adopt a kinetic theory of polariton non-equilibrium Bose-Einstein condensation, to describe the formation of off-diagonal long-range order. The theory accounts properly for the dominant role of quantum fluctuations in the condensate. In realistic situations with optical excitation at high energy, it predicts a significant depletion of the condensate cause

Vincenzo Savona, Wolfgang Langbein

We present a model for the disorder of the heterointerfaces in GaAs quantum wells including long-range components like monolayer island formation induced by the surface diffusion during the epitaxial growth process. Taking into account both interfaces, a disorder potential for the exciton motion in the quantum well plane is derived. The excitonic optical pro

M. Ya. Amusia, A. S. Baltenkov

It is demonstrated that the fullerene shell affects dramatically the radiative and Auger vacancy decay of an endohedral atom A@C60. The collectivized electrons of the C60 shell add new possibilities for radiative and non-radiative decays similar to that in ordinary atoms where initial and final state vacancies almost always belong to different subshells. It

Luciano da Fontoura Costa

The current article shows how concepts from the areas of random walks, Markov chains, complex networks and image analysis can be naturally combined in order to provide a unified and biologically plausible model relating saliency and visual attention. Two types of models are proposed: (i) images are converted into complex networks by considering pixels as nod

A. Leviatan

The dynamics at the critical-point of a general first-order quantum phase transition in a finite system is examined, from an algebraic perspective. Suitable Hamiltonians are constructed whose spectra exhibit coexistence of states corresponding to two degenerate minima in the energy surface separated by an arbitrary barrier. Explicit expressions are derived f

Sergey Kitaev

We review selected known results on partially ordered patterns (POPs) that include co-unimodal, multi- and shuffle patterns, peaks and valleys ((modified) maxima and minima) in permutations, the Horse permutations and others. We provide several (new) results on a class of POPs built on an arbitrary flat poset, obtaining, as corollaries, the bivariate generat

Carlos Castano-Bernard

Let X_0+(N) be the Atkin-Lehner quotient of the modular curve X_0(N) associated to the Fricke involution wN. Assume N > 3 prime and endow the real locus X+ 0 (N)(R) with the real topology. In this paper we revisit a special case of result due to Ogg on the connected components of X_0+(N)(R). Then we obtain a formula for the homology class of each connected c

A. Toschi, A. A. Katanin, K. Held

We develop a diagrammatic approach with local and nonlocal self-energy diagrams, constructed from the local irreducible vertex. This approach includes the local correlations of dynamical mean field theory and long-range correlations beyond. It allows for example to describe (para-)magnons and weak localization effects in strongly correlated systems. As a fir

T. Padmanabhan

Nearly seventy per cent of the energy density in the universe is unclustered and exerts negative pressure. This conclusion -- now supported by numerous observations -- poses the greatest challenge for theoretical physics today. I discuss this issue with special emphasis on the cosmological constant as the possible choice for the dark energy. Several curious

Noam Soker

We examine recent studies on the formation rate of planetary nebulae and find this rate to be about one-third of the formation rate of white dwarfs. This implies than only about one-third of all planetary nebulae that evolve to form white dwarfs are actually bright enough to be observed. This finding corresponds with the claim that it is necessary for a bina

Victor Ivrii

I study the Schroedinger operator with the strong magnetic field, considering links between geometry of magnetic field, classical and quantum dynamics associated with operator and spectral asymptotics.

Mladen Barbic, Axel Scherer

The methodology for obtaining two- and three-dimensional magnetic resonance images by using azimuthally symmetric dipolar magnetic fields from ferromagnetic spheres is described. We utilize the symmetric property of a geometric sphere in the presence of a large externally applied magnetic field to demonstrate that a complete two- or three-dimensional structu

Andrew Theyken Bench

Using only a thought experiment and Einstein's correspondence principal, a model is derived that correctly predicts the Schwarzschild time dilation expression in limiting cases. The method requires almost no prerequisite knowledge from the student and is carried out with only algebraic techniques, allowing the introduction of a mathematical example of ge

Renat M. Yulmetyev, Sergey A. Demin, Peter Hänggi

In this chapter we present a new approach to the study of manifestations of chaos in real complex system. Recently we have achieved the following result. In real complex systems the informational measure of chaotic chatacter (IMC) can serve as a reliable quantitative estimation of the state of a complex system and help to estimate the deviation of this state

Renat M. Yulmetyev, Sergey A. Demin, Oleg Yu. Panischev, Peter Hänggi

Regular and stochastic behavior in the time series of Parkinsonian pathological tremor velocity is studied on the basis of the statistical theory of discrete non-Markov stochastic processes and flicker-noise spectroscopy. We have developed a new method of analyzing and diagnosing Parkinson's disease (PD) by taking into consideration discreteness, fluctua

S. E. Shnoll, V. A. Panchelyuga

As shown in a number of our works, the form of histograms - distributions of amplitude fluctuations - varies regularly in time, with these variations being similar for processes of any nature, from biochemical reactions to noise in the gravitational antenna and all types of the radioactive decay. In particular, we have revealed basic laws, suggesting a cosmo

Renat M. Yulmetyev, Sergey A. Demin, Oleg Yu. Panischev, Peter Hänggi

In this paper we consider the age-related alterations of heart rate variability on the basis of the study of non-Markovian effects. The age dynamics of relaxation processes is quantitatively described by means of local relaxation parameters, calculated by the specific localization procedure. We offer a quantitative informational measure of non-Markovity to e

E. Comay

Criteria for defining errors of a physical theory are formulated. It is shown that the Special Theory of Relativity (STR) has a solid mathematical basis. An enormous amount of experiments carried out in particle physics use beams of particles having a very high energy. The data of these experiments are consistent with STR and support our confidence that STR

P. Fraundorf

Consider the network of elements connected by adjacency in atomic number and periodic table column. If all elements except H-He are connected by identical springs and constrained to a z-spiral in 2D, a map sans spring-crossing results for various values of rest length in units of the H-He distance. If the z-spiral is removed, and the network allowed to relax

Charles F. Doran, Michael G. Faux, S. James Gates,, Tristan Hubsch

An off-shell representation of supersymmetry is a representation of the super Poincare algebra on a dynamically unconstrained space of fields. We describe such representations formally, in terms of the fields and their spacetime derivatives, and we interpret the physical concept of engineering dimension as an integral grading. We prove that formal graded off

Stéphan Clémençon, Gábor Lugosi, Nicolas Vayatis

The problem of ranking/ordering instances, instead of simply classifying them, has recently gained much attention in machine learning. In this paper we formulate the ranking problem in a rigorous statistical framework. The goal is to learn a ranking rule for deciding, among two instances, which one is "better," with minimum ranking risk. Since the na

Victor Ivrii

Survey: In this paper I consider sharp spectral asymptotics for multidimensional magnetic Schrödinger operator with irregular coefficients with respect to two parameters -- semiclassical parameter $h$ and coupling parameter $μ$. There are few principally different cases, depending on dimension, rank of magnetic intensity matrix, relation between $h$ and $μ$

Frederik S Herzberg

Consider a discrete finite-dimensional, Markovian market model. In this setting, discretely sampled American options can be priced using the so-called ``non-recombining'' tree algorithm. By successively increasing the number of exercise times, the American option price itself can be computed; for combinatorial reasons, we shall consider a recursive a

Jean-Francois Burnol

We study Hilbert space aspects of the Klein-Gordon equation in two-dimensional spacetime. We associate to its restriction to a spacelike wedge a scattering from the past light cone to the future light cone, which is then shown to be (essentially) the Hankel transform of order zero. We apply this to give a novel proof, solely based on the causality of this sp

S. Torquato, F. H. Stillinger

Sphere packings in high dimensions interest mathematicians and physicists and have direct applications in communications theory. Remarkably, no one has been able to provide exponential improvement on a 100-year-old lower bound on the maximal packing density due to Minkowski in $d$-dimensional Euclidean space $\Re^d$. The asymptotic behavior of this bound is

E. Ryckman, M. Visan

We obtain global well-posedness, scattering, uniform regularity, and global $L^6_{t,x}$ spacetime bounds for energy-space solutions to the defocusing energy-critical nonlinear Schrödinger equation in $\R\times\R^4$. Our arguments closely follow those of Colliander-Keel-Staffilani-Takaoka-Tao, though our derivation of the frequency-localized interaction Moraw

A. B. Pimenov, K. V. Stepanyantz

A method of Feynman diagrams summation, based on using Schwinger-Dyson equations and Ward identities, is verified by calculating some four-loop diagrams in N=1 supersymmetric electrodynamics, regularized by higher derivatives. In particular, for the considered diagrams correctness of an additional identity for Green functions, which is not reduced to the gau

Anca Tureanu

In the framework of quantum field theory (QFT) on noncommutative (NC) space-time with the symmetry group $O(1,1)\times SO(2)$, we prove that the Jost-Lehmann-Dyson representation, based on the causality condition taken in connection with this symmetry, leads to the mere impossibility of drawing any conclusion on the analyticity of the $2\to 2$-scattering amp

Valery N. Marachevsky

A pedagogical introduction to the heat kernel technique, zeta function and Casimir effect is presented. Several applications are considered. First we derive the high temperature asymptotics of the free energy for boson fields in terms of the heat kernel expansion and zeta function. Another application is chiral anomaly for local (MIT bag) boundary conditions

Sukanta Dutta, Kaoru Hagiwara, Qi-Shu Yan

We study the impact of LEP2 constraints on the dimensionless coefficients of the electroweak chiral Lagrangian on the precision observables using the improved renormalization group equations. We find that the current uncertainty in the triple and quartic gauge boson couplings can accommodate electroweak symmetry breaking models with $S(Λ=1 \textrm{TeV}) > 0$

Eric Gourgoulhon

This lecture provides some introduction to perfect fluid dynamics within the framework of general relativity. The presentation is based on the Carter-Lichnerowicz approach. It has the advantage over the more traditional approach of leading very straightforwardly to important conservation laws, such as the relativistic generalizations of Bernoulli's theor

Sergei Kopeikin

Relationship between the speed of gravity c_g and the speed of light c_e in the bi-metric theory of gravity is discussed. We reveal that the speed of light is a function of the speed of gravity which is a primary fundamental constant. Thus, experimental measurement of relativistic bending of light propagating in time-dependent gravitational field directly co

Joseph Y. halpern, Leandro Chaves Rego

Awareness has been shown to be a useful addition to standard epistemic logic for many applications. However, standard propositional logics for knowledge and awareness cannot express the fact that an agent knows that there are facts of which he is unaware without there being an explicit fact that the agent knows he is unaware of. We propose a logic for reason

Joseph Y. Halpern, Leandro Chaves Rego

There has been a great of work on characterizing the complexity of the satisfiability and validity problem for modal logics. In particular, Ladner showed that the validity problem for all logics between K, T, and S4 is {\sl PSPACE}-complete, while for S5 it is {\sl NP}-complete. We show that, in a precise sense, it is \emph{negative introspection}, the axiom

A. P. Castro, H. W. Leite Alves

We present, in this work, our preliminary results of a systematic theoretical study of the adsorption of N over As-terminated GaAs (100) (2$\times$1) surfaces. We analyzed the changes in the bond-lenghts, bond-angles and the energetics involved before and after deposition. Our results show that the N-atoms will prefer the unoccupied sites of the surface, clo

Eric Pop, David Mann, John Reifenberg, Kenneth Goodson

This work represents the first electro-thermal study of metallic single-wall carbon nanotubes (SWNTs) for interconnect applications. Experimental data and careful modeling reveal that self-heating is of significance in short (1 < L < 10 um) nanotubes under high-bias. The low-bias resistance of micron scale SWNTs is also found to be affected by optical phonon

R. L. Badzey, G. Zolfagharkhani, S. -B. Shim, A. Gaidarzhy

Bestriding the realms of classical and quantum mechanics, nanomechanical structures offer great promise for a huge variety of applications, from computer memory elements \cite{badzey04} and ultra-fast sensors to quantum computing. Intriguing as these possibilities are, there still remain many important hurdles to overcome before nanomechanical structures app

L. Brey, H. A. Fertig

We study the electronic states of narrow graphene ribbons (``nanoribbons&#39;&#39;) with zigzag and armchair edges. The finite width of these systems breaks the spectrum into an infinite set of bands, which we demonstrate can be quantitatively understood using the Dirac equation with appropriate boundary conditions. For the zigzag nanoribbon we demonstrate t

U. K. Roessler, A. N. Bogdanov, C. Pfleiderer

Supplementary information for our manuscript, entitled &#39;Spontaneous Skyrmion Ground States of Magnetic Metals&#39;, cond-mat/0603103, is presented. The physical nature of the gradient terms of our generalized micromagnetic model for ferromagnets with softened longitudinal fluctuations is explained. The relationship of our micromagnetic model with the spi

U. K. Roessler, A. N. Bogdanov, C. Pfleiderer

Since the 1950s Heisenberg and others have attempted to explain the appearance of countable particles in quantum field theory in terms of stable localized field configurations. As an exception Skyrme&#39;s model succeeded to describe nuclear particles as localized states, so-called &#39;skyrmions&#39;, within a non-linear field theory. Skyrmions are a charac

S. Courty, A. R. Tajbakhsh, E. M. Terentjev

Imprinting of cholesteric textures in a polymer network is a method of preserving a macroscopically chiral phase in a system with no molecular chirality. By modifying the elastics properties of the network, the resulting stored helical twist can be manipulated within a wide range since the imprinting efficiency depends on the balance between the elastics con

V. I. Belyavsky, Yu. V. Kopaev

We develop Ginzburg-Landau approach to the problem of superconducting pairing with large momentum under screened Coulomb repulsion (eta_K-pairing). Two-component order parameter arising in this scheme can be associated with charge and orbital current degrees of freedom of the relative motion of eta_K-pair corresponding to superconducting and orbital antiferr

N. Bulut, H. Matsueda, T. Tohyama, S. Maekawa

The angle-resolved photoemission spectrum of the organic conductor TTF-TCNQ exhibits an unusual transfer of spectral weight over a wide energy range for temperatures 60K<T<260K. In order to investigate the origin of this finding, here we report numerical results on the single-particle spectral weight A(k,omega) for the one-dimensional (1D) Hubbard model and,

Zheng-Yu Weng, Xiao-Liang Qi

The pseudogap phase is considered as a new state of matter in the phase string model of the doped Mott insulator, which is composed of two distinct regimes known as upper and lower pseudogap phases, respectively. The former corresponds to the formation of spin singlet pairing and the latter is characterized by the formation of the Cooper pair amplitude and d

Yoav Tsori, David Andelman

We present few ordering mechanisms in block copolymer melts in the coarse-graining approach. For chemically homogeneous or modulated confining surfaces, the surface ordering is investigated above and below the order-disorder temperature. In some cases the copolymer deformation near the surface is similar to the copolymer morphology in bulk grain boundaries.

H. Bary-Soroker, H. Diamant

We study the relaxation modes of an interface between a lyotropic lamellar phase and a gas or a simple liquid. The response is found to be qualitatively different from those of both simple liquids and single-component smectic-A liquid crystals. At low rates it is governed by a non-inertial, diffusive mode whose decay rate increases quadratically with wavenum

Z. C. Tu, Q. X. Li, X. Hu

The formation of ZnO nanorings and nanohelices with large polar surfaces observed in experiments [Nano Lett. 3, 1625 (2003); J. Am. Chem. Soc. 126, 6703 (2004)] is shown to be a result of the competition between elastic energy, spontaneous polarization-induced surface energy, volume energy, and defect-induced energy. It is found that nanorings and nanohelice

George Efstathiou, Sirichai Chongchitnan

We review the prospects for detecting tensor modes generated during inflation by CMB polarization experiments and by searching for a stochastic gravitational wave background with laser interferometers in space. We tackle the following two questions: (i) what does inflation predict for the tensor fluctuations? (ii) is it really worth building experiments that

Elmar Koerding, Heino Falcke, Sephane Corbel

The idea of a unified description of supermassive and stellar black holes has been supported by the extension of the empirical radio/X-ray correlation from X-ray binaries to active galactic nuclei through the inclusion of a mass term. This has lead to the so-called fundamental plane of black hole activity in the black hole mass, radio and X-ray luminosity sp

A. C. Carciofi, J. E. Bjorkman, A. S. Miroshnichenko, A. M. Magalhães

We present self-consistent solutions for the disk structure of classical Be stars. Our disk model is hydrostatically supported in the vertical direction and the radial structure is governed by viscosity ($α$-disks). We perform three-dimensional non-LTE Monte Carlo simulations to calculate simultaneously both the equilibrium temperature and Hydrogen level pop

S. Sadeh, Y. Rephaeli, J. Silk

The main statistical properties of the Sunyaev-Zeldovich (S-Z) effect - the power spectrum, cluster number counts, and angular correlation function - are calculated and compared within the framework of two density fields which differ in their predictions of the cluster mass function at high redshifts. We do so for the usual Press and Schechter mass function,

V. G. Gurzadyan, S. -S. Xue

The formula for the dark energy, derived by Padmanabhan in a recent Letter to Editor (Class.Quantum Grav. September 2005, the formula given in its Abstract), was actually derived 4 years earlier ourselves in astro-ph/0105245; Mod.Phys.Lett. A18, 561, 2003. Among dozens of references in that Letter, no quotation to our paper. Based on the same Zeldovich idea

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

We investigate the time evolution of Gaussian wave packet (GWP) in the tight-binding chain with uniform nearest neighbor (NN) hopping integral. Analytical analysis and numerical simulations show that the fractional revival of the quantum state occurs in such system, i.e., at appropriate time, a GWP can evolve into many copies of the initial state at differen

Anne Moreau

I prefer taking off this paper for the moment because of a mistake in the lemma 2.1 of the secund version. Precisely, in the proof of this lemma, it is not clear that the morphism $r\_j$ is flat, that I claim it.

Jonathan Barrett, Carlton M. Caves, Bryan Eastin, Matthew B. Elliott

We propose a communication-assisted local-hidden-variable model that yields the correct outcome for the measurement of any product of Pauli operators on an arbitrary graph state, i.e., that yields the correct global correlation among the individual measurements in the Pauli product. Within this model, communication is restricted to a single round of message

Z. Burda, A. Jarosz, J. Jurkiewicz, M. A. Nowak

We apply the concept of free random variables to doubly correlated (Gaussian) Wishart random matrix models, appearing for example in a multivariate analysis of financial time series, and displaying both inter-asset cross-covariances and temporal auto-covariances. We give a comprehensive introduction to the rich financial reality behind such models. We explai

Akimichi Takemura, Ruriko Yoshida

Does a given system of linear equations with nonnegative constraints have an integer solution? This is a fundamental question in many areas. In statistics this problem arises in data security problems for contingency table data and also is closely related to non-squarefree elements of Markov bases for sampling contingency tables with given marginals. To stud

A. Tawfik

Screening masses of different hadronic states are studied in thermal and dense medium on lattice. It has been found that screening masses increase with the temperature. In deconfinement phase, chemical potential enhances the screening masses. We use the normalization with respect to lowest Matsubara frequency to characterize dissolving of hadronic bound stat

Zong-Kuan Guo, Nobuyoshi Ohta, Yuan-Zhong Zhang

We develop a theoretical method of constructing the scalar (quintessence or phantom) potential directly from the dimensionless dark energy function X(z), the dark energy density in units of its present value. We apply our method to two parametrizations of the dark energy density, the quiessence-Lambda ansatz and the generalized Chaplygin gas model, and discu

D. K. Park

The polar perturbation is examined when the spacetime is expressed by a 4d metric induced from higher-dimensional Schwarzschild geometry. Since the spacetime background is not a vacuum solution of 4d Einstein equation, the various general principles are used to understand the behavior of the energy-momentum tensor under the perturbation. It is found that alt

Davi C. Rodrigues, Clovis Wotzasek

We extend the ordinary 3D electromagnetic duality to the noncommutative (NC) space-time through a Seiberg-Witten map to second order in the noncommutativity parameter (theta), defining a new scalar field model. There are similarities with the 4D NC duality, these are exploited to clarify properties of both cases. Up to second order in theta, we find that dua

Masahito Hayashi

We focus on classical and quantum list decoding. The capacity of list decoding was obtained by Nishimura in the case when the number of list does not increase exponentially. However, the capacity of the exponential-list case is open even in the classical case while its converse part was obtained by Nishimura. We derive the channel capacities in the classical

Masanao Ozawa

Recently, Wallentowitz and Toschek [Phys. Rev. A 69, 046101 (2005)] criticized the assertion made by Hotta and Morikawa [Phys. Rev. A 69, 052114 (2004)] that distant indirect measurements do not cause the quantum Zeno effect, and claimed that their proof is faulty and that their claim is unfounded. Here, it is shown that the argument given by Wallentowitz an

Kathryn Whitman, Alessandro Morbidelli, Robert Jedicke

We estimate the total number and the slope of the size frequency distribution (SFD) of dormant Jupiter Family Comets (JFCs) by fitting a one-parameter model to the known population. We first select 61 Near Earth Objects (NEOs) that are likely to be dormant JFCs because their orbits are dynamically coupled to Jupiter (Bottke et al, 2002). Then, from the numer

V. M. Gandhimathi, K. Murali, S. Rajasekar

We study the stochastic resonance phenomenon in the overdamped two coupled anharmonic oscillators with Gaussian noise and driven by different external periodic forces. We consider (i) sine, (ii) square, (iii) symmetric saw-tooth, (iv) asymmetric saw-tooth, (v) modulus of sine and (vi) rectified sinusoidal forces. The external periodic forces and Gaussian noi

Victor Ivrii

I consider magnetic Schrödinger operator in dimension $d=2$ assuming that coefficients are smooth and magnetic field is non-degenerating. Then I extend the remainder estimate $O(μ^{-1}h^{-1}+1)$ derived in \cite{Ivr1} for the case when $V/F$ has no stationary points to the case when it has non-degenerating stationary points. If some of them are saddles and $

Victor Ivrii

I consider the same operator as in part I assuming however that $μ\ge Ch^{-1}$ and $V$ is replaced by $(2l+1)μh F+W$ with $l\in \bZ^+$. Under some non-degeneracy conditions I recover remainder estimates up to $O \bigl(μ^{-{\frac 1 ν}}h^{-1} +1\bigr)$ but now case $μ\ge Ch^{-ν}$ is no more forbidden and the principal part is of magnitude $μh^{-1}$.

Eric Babson

We show that reconstructing a tree from order information on triples is NP-hard. This is in contrast to the case for ultra-metrics and for subtree information on quadruples which are both known to allow polynomial time reconstruction.

Victor Ivrii

I consider two-dimensional Schrödinger operator with degenerating magnetic field and in the generic situation I derive spectral asymptotics as $h\to +0$ and $μ\to +\infty$ where $h$ and $μ$ are Planck and coupling parameters respectively. The remainder estimate is $O(μ^{-{\frac 1 2}}h^{-1})$ which is between $O(μ^{-1}h^{-1})$ valid as magnetic field non-dege

Jirô Akahori, Chihiro Uenishi, Kouji Yano

In this paper a stochastic equation on compact groups in discrete negative time is studied. This is closely related to Tsirelson&#39;s stochastic differential equation, of which any solution is non-strong. How the group action reflects on the set of solutions is investigated. It is applied to generalize Yor&#39;s result and give a necessary and sufficient co

Nikolay Tzvetkov

We study Gibbs measures invariant under the flow of the NLS on the unit disc of $\R^2$. For that purpose, we construct the dynamics on a phase space of limited Sobolev regularity and a wighted Wiener measure invariant by the NLS flow. The density of the measure is integrable with respect to the Wiener measure for sub cubic nonlinear interactions. The existen

Ulrich Derenthal

Let S_r be the blow-up of P^2 in r general points, i.e., a smooth Del Pezzo surface of degree 9-r. For r <= 7, we determine the quadratic equations defining its Cox ring explicitly. The ideal of the relations in Cox(S_8) is calculated up to radical. As conjectured by Batyrev and Popov, all the generating relations are quadratic.

H. Inassaridze

We provide and study an equivariant theory of group (co)homology of a group G with coefficients in a gamma-equivariant G-module A, when a separate group &#34;gamma&#34; acts on G and A, generalizing the classical Eilenberg-MacLane (co)homology of groups. Relationship with equivariant cohomology of topological spaces is established and application to algebrai

Luiz Renato Fontes, Roberto H. Schonmann

We study the threshold $theta geq 2$ contact process on a homogeneous tree $T_b$ of degree $kappa = b + 1$, with infection parameter $lambda geq 0$ and started from a product measure with density $p$. The corresponding mean-field model displays a discontinuous transition at a critical point $lambda_c^{MF}(kappa,theta)$ and for $lambda geq lambda_c^{MF}(kappa

Yongxi Cheng

An \emph{antimagic labeling} of a finite undirected simple graph with $m$ edges and $n$ vertices is a bijection from the set of edges to the integers $1,...,m$ such that all $n$ vertex sums are pairwise distinct, where a vertex sum is the sum of labels of all edges incident with the same vertex. A graph is called \emph{antimagic} if it has an antimagic label

Motohico Mulase, Brad Safnuk

We present in this paper a differential version of Mirzakhani&#39;s recursion relation for the Weil-Petersson volumes of the moduli spaces of bordered Riemann surfaces. We discover that the differential relation, which is equivalent to the original integral formula of Mirzakhani, is a Virasoro constraint condition on a generating function for these volumes.

Richard B. Melrose, Frederic Rochon

A families index theorem in K-theory is given for the setting of Atiyah, Patodi and Singer of a family of Dirac operators with spectral boundary condition. This result is deduced from such a K-theory index theorem for the calculus of cusp, or more generally fibred cusp, pseudodifferential operators on the fibres (with boundary) of a fibration; a version of P

Mike Krebs

To each connected component in the space of semisimple representations from the orbifold fundamental group of the base orbifold of a Seifert fibered homology 3-sphere into the Lie group U(2,1), we associate a real number called the &#34;orbifold Toledo invariant.&#34; For each such orbifold, there exists an elliptic surface over it, called a Dolgachev surfac

Frederik S. Herzberg

In this paper, it is shown that Bermudan option pricing based on either the réduite (in a one-dimensional setting: piecewise harmonic interpolation) or cubature -- is sensible from an economic vantage point: Any sequence of thus-computed prices for Bermudan options with increasing sets of exercise times is increasing. Furthermore, under certain regularity as

Frederic Rochon

In the framework of fibred cusp operators on a manifold $X$ associated to a boundary fibration $Φ: \pa X\to Y$, the homotopy groups of the space of invertible smoothing perturbations of the identity are computed in terms of the K-theory of $T^{*}Y$. It is shown that there is a periodicity, namely the odd and the even homotopy groups are isomorphic among them

A. Curioni

We present results from the first exposure of a liquid Ar time projection chamber to a neutrino beam. The data have been collected in 1997 with a 50 liter ICARUS-like chamber located between the CHORUS and NOMAD experiment at the CERN West Area Neutrino Facility. We focus on the analysis of quasi-elastic interactions; despite the limited size of the detector

J. Antos, M. Babik, A. W. Chan, Y. C. Chen

The data production farm for the CDF experiment is designed and constructed to meet the needs of the Run II data collection at a maximum rate of 20 MByte/sec during the run. The system is composed of a large cluster of personal computers (PCs) with a high-speed network interconnect and a custom design control system for the flow of data and the scheduling of

A. Juste

Ten years after its discovery at the Tevatron collider, we still know little about the top quark. Its large mass suggests it may play a key role in the mechanism of Electroweak Symmetry Breaking (EWSB), or open a window of sensitivity to new physics related to EWSB and preferentially coupled to it. To determine whether this is the case, precision measurement

Katsutoshi Fujiwara, Akira Ishii, Toshikazu Ebisuzaki, Atsushi Kobayashi

We have investigated the stability of the 1ML-GaN on the O-polarity ZnO(000-1) interface structure using the first-principles calculation. We have found in our calculated results that the most stable structure for the 1ML-GaN on the O-polarity ZnO(000-1) interface has the N-polarity. However, we have found that the results of the adatom dynamics on the O-ter

Guang-Ri Jin, Chul Koo Kim, Kyun Nahm

We propose a new measurement scheme for the atom-molecule dark state by using electromagnetically induced transparency (EIT) technique. Based on a density-matrix formalism, we calculate the absorption coefficient numerically. The appearance of the EIT dip in the spectra profile gives clear evidence for the creation of the dark state in the atom-molecule Bose

Michael Bortz, Sergey Sergeev

We investigate the exact solution of the q-deformed one-dimensional Bose gas to derive all integrals of motion and their corresponding eigenvalues. As an application, the thermodynamics is given and compared to an effective field theory at low temperatures.

Zheng-Cheng Gu, Geoff Warner, Fei Zhou

In this Letter we map out the mean field energy potential landscape of fermion pairing states with population imbalance near broad Feshbach Resonances. We apply the landscape to investigate the nature of phase separation, when the Hilbert space is subject to the constraint of constant population imbalance. We calculate the scattering length dependence of the

M. Huijben, G. Rijnders, D. H. A. Blank, S. Bals

Perovskite oxides exhibit a plethora of exceptional electronic properties, providing the basis for novel concepts of oxide-electronic devices. The interest in these materials is even extended by the remarkable characteristics of their interfaces. Studies on single epitaxial connections between the two wide-bandgap insulators LaAlO3 and SrTiO3 have revealed t

Hitoshi Seo, Jaime Merino, Hideo Yoshioka, Masao Ogata

Theoretical studies on charge ordering phenomena in quarter-filled molecular (organic) conductors are reviewed. Extended Hubbard models including not only the on-site but also the inter-site Coulomb repulsion are constructed in a straightforward way from the crystal structures, which serve for individual study on each material as well as for their systematic

Davide Sarchi, Vincenzo Savona

We develop a kinetic theory of microcavity polaritons in presence of both Coulomb and polariton-phonon interaction, obeying particle number conservation. We study the growth of a macroscopic population of condensed particles in the lowest polariton state, under steady-state incoherent excitation of higher energy states. The collective excitation spectrum, re

Aviv Ofir, Erez N. Ribak

Intensity interferometry removes the stringent requirements on mechanical precision and atmospheric corrections that plague all amplitude interferometry techniques at the cost of severely limited sensitivity. A new idea we recently introduced, very high redundancy, alleviates this problem. It enables the relatively simple construction (~1cm mechanical precis

Aviv Ofir, Erez N. Ribak

Stellar amplitude interferometry is limited by the need to have optical distances fixed and known to a fraction of the wavelength. We suggest reviving intensity interferometry, which requires hardware which is many orders of magnitude less accurate, at the cost of more limited sensitivity. We present an algorithm to use the very high redundancy of a uniform

John E. Vaillancourt

The determination of the true source polarization given a set of measurements is complicated by the requirement that the polarization always be positive. This positive bias also hinders construction of upper limits, uncertainties, and confidence regions, especially at low signal-to-noise levels. We generate the likelihood function for linear polarization mea

L. D. Duffy, P. Sikivie, D. B. Tanner, S. J. Asztalos

We have performed a high resolution search for galactic halo axions in cold flows using a microwave cavity detector. The analysis procedure and other details of this search are described. No axion signal was found in the mass range 1.98-2.17 micro-eV. We place upper limits on the density of axions in local discrete flows based on this result.

K. Asano, S. Nagataki

We simulate neutrino production in a gamma-ray burst (GRB) with the most detailed method to date. We show that the highest energy neutrinos from GRBs mainly come from kaons. Although there is little chance to detect such neutrinos, attempts of detection are very important to prove physical conditions in GRBs.