July 2006 arXiv papers — page 45

Qionglei Chen, Changxing Miao, Zhifei Zhang

We show a new Bernstein's inequality which generalizes the results of Cannone-Planchon, Danchin and Lemarié-Rieusset. As an application of this inequality, we prove the global well-posedness of the 2D quasi-geostrophic equation with the critical and super-critical dissipation for the small initial data in the critical Besov space, and local well-posednes

Hiraku Kawanoue

This paper represents the main portion of the Ph.D. Thesis of the author, and is the first of the series of four papers, which is a joint work with K. Matsuki as a whole. We present a program toward constructing an algorithm for resolution of singularities in positive characteristic. We would like to emphasize, however, that the program is actually valid in

Debarati Chatterjee, Debades Bandyopadhyay

We investigate the effect of exotic matter in particular, hyperon matter on neutron star properties such as equation of state (EoS), mass-radius relationship and bulk viscosity. Here we construct equations of state within the framework of a relativistic field theoretical model. As hyperons are produced abundantly in dense matter, hyperon-hyperon interaction

M. Heller, L. Pysiak, W. Sasin

We present a model unifying general relativity and quantum mechanics. The model is based on the (noncommutative) algebra \mbox{\cal A} on the groupoid Γ= E \times G where E is the total space of the frame bundle over spacetime, and G the Lorentz group. The differential geometry, based on derivations of \mbox{\cal A}, is constructed. The eigenvalue equation f

Todor E. Milanov, Hsian-Hua Tseng

Let $M_{k,m}$ be the space of Laurent polynomials in one variable $x^k + t_1 x^{k-1}+... t_{k+m}x^{-m},$ where $k,m\geq 1$ are fixed integers and $t_{k+m}\neq 0$. According to B. Dubrovin \cite{D}, $M_{k,m}$ can be equipped with a semi-simple Frobenius structure. In this paper we prove that the corresponding descendant and ancestor potentials of $M_{k,m}$ (d

Ji-rong Ren, Ran Li, Yi-shi Duan

We discuss an object from algebraic topology, Hopf invariant, and reinterpret it in terms of the $ϕ$-mapping topological current theory. The main purpose in this paper is to present a new theoretical framework which can directly give the relationship between Hopf invariant and the linking numbers of the higher dimensional submanifolds of Euclidean space $R^{

Hariharan Narayanan

This paper contains results relating currents and voltages in resistive networks to appropriate random trees or forests in those networks.

Petarpa Boonserm, Matt Visser, Silke Weinfurtner

The Tolman-Oppenheimer-Volkov [TOV] equation constrains the internal structure of general relativistic static perfect fluid spheres. We develop several "solution generating" theorems for the TOV, whereby any given solution can be "deformed" to a new solution. Because the theorems we develop work directly in terms of the physical observables -

P. A. Toale

IceCube is currently being built deep in the glacial ice beneath the South Pole. In its second year of construction, it is already larger than its predecessor, AMANDA. AMANDA continues to collect high energy neutrino and muon data as an independent detector until it is integrated with IceCube. After introducing both detectors, recent results from AMANDA and

Ariel Pacetti, Gonzalo Tornaría

Let f be a newform of weight two and composite level N. We show how to compute weight 3/2 modular forms "associated" to f whose Fourier coefficients are related to the central values of quadratic twists (real and imaginary) of f. We will focus on examples for levels N=27, N=15, and N=75, which exhibit most aspects of our methods.

Nataliia O. Cherkashyna, Constantin V. Usenko

Identity of electrons leads to description of their states by symmetrical or anti-symmetrical combination of free coherent states. Due to the coordinate uncertainty potential energy of the Coulomb repulsing is limited from above and so when energy of electrons is large enough, electrons go through each other, without noticing one another. We show existence o

Constantin V. Usenko

This report is about contradiction between fidelity needed to determine the entanglement and concomitant noise that always accompanies precise measurement. Account of quantum properties of field leads to additional noise caused by multiple particle creation through nonunitarity of quantum field representation in embedded sections of space (Unruh noise). Caus

M. Sbragaglia, A. Prosperetti

This paper studies the nature of the effective velocity boundary conditions for liquid flow over a plane boundary on which small free-slip islands are randomly distributed. It is found that, to lowest order in the area fraction $β$ covered by free-slip regions with characteristic size $a$, a macroscopic Navier-type slip condition emerges with a slip length o

Maurice de Gosson, Serge de Gosson, Paolo Piccione

Using invariance by fixed-endpoints homotopies and a generalized notion of symplectic Cayley transform, we prove a product formula for the Conley--Zehnder index of continuous paths with arbitrary endpoints in the symplectic group. We discuss two applications of the formula, to the metaplectic group and to periodic solutions of Hamiltonian systems.

B. J. K. Kleijn, A. W. van der Vaart

We consider the asymptotic behavior of posterior distributions if the model is misspecified. Given a prior distribution and a random sample from a distribution $P_0$, which may not be in the support of the prior, we show that the posterior concentrates its mass near the points in the support of the prior that minimize the Kullback--Leibler divergence with re

Fumiyasu Komaki

We investigate shrinkage priors for constructing Bayesian predictive distributions. It is shown that there exist shrinkage predictive distributions asymptotically dominating Bayesian predictive distributions based on the Jeffreys prior or other vague priors if the model manifold satisfies some differential geometric conditions. Kullback--Leibler divergence f

Marianna Pensky

The present paper investigates theoretical performance of various Bayesian wavelet shrinkage rules in a nonparametric regression model with i.i.d. errors which are not necessarily normally distributed. The main purpose is comparison of various Bayesian models in terms of their frequentist asymptotic optimality in Sobolev and Besov spaces. We establish a rela

V. Zhukovin, Z. Alimbarashvili

In the item there are presented Interval Structure allow to extend the class of multicriteria decision making problems including incomplete Initial Information. this step will facilitate dada gathering in pairs matching for decision making.

Vladimir N. Kulikov, Hendrik P. Lopuhaä

We investigate the behavior of the nonparametric maximum likelihood estimator $\hat{f}_n$ for a decreasing density $f$ near the boundaries of the support of $f$. We establish the limiting distribution of $\hat{f}_n(n^{-α})$, where we need to distinguish between different values of $0<α<1$. Similar results are obtained for the upper endpoint of the support, i

Peter J. Bickel, Ya&#39;acov Ritov, Thomas M. Stoker

We introduce a new framework for constructing tests of general semiparametric hypotheses which have nontrivial power on the $n^{-1/2}$ scale in every direction, and can be tailored to put substantial power on alternatives of importance. The approach is based on combining test statistics based on stochastic processes of score statistics with bootstrap critica

Magalie Fromont, Béatrice Laurent

Given an i.i.d. sample drawn from a density $f$, we propose to test that $f$ equals some prescribed density $f_0$ or that $f$ belongs to some translation/scale family. We introduce a multiple testing procedure based on an estimation of the $\mathbb{L}_2$-distance between $f$ and $f_0$ or between $f$ and the parametric family that we consider. For each sample

Damla Şentürk, Hans-Georg Müller

We consider covariate adjusted regression (CAR), a regression method for situations where predictors and response are observed after being distorted by a multiplicative factor. The distorting factors are unknown functions of an observable covariate, where one specific distorting function is associated with each predictor or response. The dependence of both r

William Crawley-Boevey, Pavel Etingof, Victor Ginzburg

We develop a new framework for noncommutative differential geometry based on double derivations. This leads to the notion of moment map and of Hamiltonian reduction in noncommutative symplectic geometry. For any smooth associative algebra B, we define its noncommutative cotangent bundle T^*B, which is a basic example of noncommutative symplectic manifold. Ap

Nick E. Mavromatos

Recent astrophysical observations, pertaining to either high-redshift supernovae or cosmic microwave background temperature fluctuations, as those measured recently by the WMAP satellite, provide us with data of unprecedented accuracy, pointing towards two (related) facts: (i) our Universe is accelerated at present, and (ii) more than 70 % of its energy cont

Sunggeun Lee, Soonkeon Nam

We consider decays of four intersecting fluxbranes which are obtained by considering a higher dimensional Kerr blackhole with four angular momentum parameters, which is the maximum number of angular momentum parameters in string/M-theory. As a result of the intersection, we get lower dimensional fluxbranes. Since generic magnetic fields break all supersymmet

Michael Dine, Assaf Shomer, Zheng Sun

We investigate, from a spacetime perspective, some aspects of Horowitz&#39;s recent conjecture that black strings may catalyze the decay of Kaluza-Klein spacetimes into a bubble of nothing. We identify classical configurations that interpolate between flat space and the bubble, and discuss the energetics of the transition. We investigate the effects of windi

E. Couce

In this talk, we present the physics case for a megaton Water Cerenkov detector in addressing some of the still pending questions in neutrino oscillations physics, particularly the measurement of leptonic CP violation. We compare different future beams that could profit from a water detector and analyse, for the case $θ_{13} \approx 3^\circ$ (the limit that

Kh. M. Beshtoev

For description of the $d, s, b$ quark mixings the Cabibbo-Kobayashi-Maskawa matrices are used but they do not contain the time dependence. In this work the analogous matrix is obtained for the case of three neutrino ($ν_{e}, ν_{μ}, ν_τ$) mixings (oscillations) in vacuum in the general case, when CP violation is absent. In contrast to the quark case this mat

Ervin Bejdakic, York Schroder

In this article, we present a new analytic result for a certain single-mass-scale four-loop vacuum (bubble) integral. We also discuss its systematic $\e$-expansion in $d=4-2\e$ as well as $d=3-2\e$ dimensions, the coefficients of which are expressible in terms of harmonic sums at infinity.

S. S. Singh, Agam K. Jha

A model of cut-off momentum distribution functions in a Quark Gluon Plasma with finite baryon chemical potential is discussed. This produces a quark gluon plasma signature in Ultra Relativistic Nuclear Collisions with a specific structure of the dilepton spectrum in the transverse momentum region of $(1-4)~GeV$ and the dilepton production rate is found to be

Junegone Chay, Chul Kim, Adam K. Leibovich, Jure Zupan

We consider in the soft-collinear effective theory semi-inclusive hadronic B decays, B-> XM, in which an energetic light meson M near the endpoint recoils against an inclusive jet X. We focus on a subset of decays where the spectator quark from the B meson ends up in the jet. The branching ratios and direct CP asymmetries are computed to next-to-leading orde

Chinmoy Bhattacharya, P. R. Mahapatra

The lifting scheme of discrete wavelet transform (DWT) is now quite well established as an efficient technique for image compression, and has been incorporated into the JPEG2000 standards. However, the potential of the lifting scheme has not been exploited in the context of correlationbased processing, such as encountered in radar applications. This paper pr

Vladimir Vovk

We analyze a new algorithm for probability forecasting of binary observations on the basis of the available data, without making any assumptions about the way the observations are generated. The algorithm is shown to be well calibrated and to have good resolution for long enough sequences of observations and for a suitable choice of its parameter, a kernel o

R. Kunert, E. Schoell

We show that elastic interactions of an array of self-assembled quantum dots in a parent material matrix are markedly distinct from the elastic field created by a single point defect, and can explain the observed abrupt correlation--anticorrelation transition in semiconductor quantum dot stacks. Finite volume effects of the quantum dots are shown to lead to

Sung-Sik Lee, Patrick A. Lee, T. Senthil

Recent experiments on the organic compound $κ-(BEDT-TTF)_2 Cu_2 (CN)_3$ raise the possibility that the system may be described as a quantum spin liquid. Here we propose a pairing state caused by the `Amperean&#39; attractive interaction between spinons on a Fermi surface mediated by the U(1) gauge field. We show that this state can explain many of the observ

Gurpreet S. Matharoo, M. S. Gulam Razul, Peter H. Poole

We use the ``isoconfigurational ensemble&#39;&#39; [Phys. Rev. Lett. {\bf 93}, 135701 (2004)] to analyze both dynamical and structural properties in simulations of a glass forming molecular liquid. We show that spatially correlated clusters of low potential energy molecules are observable on the time scale of structural relaxation, despite the absence of spa

Keiji Yada, Hiroshi Kontani

We study the renormalized Coulomb interactions due to retardation effect in Na$_x$CoO$_2$. Although the Morel-Anderson&#39;s pseudo potential for $a_{1g}$ orbital $μ^*_{a1g}$ is relatively large because the direct Coulomb repulsion $U$ is large, that for interband transition between $a_{1g}$ and $e_g&#39;$ orbitals $μ^*_{a1g,eg&#39;}$ is very small since the

Keiji Yada, Hiroshi Kontani

We study the depairing effect due to Coulomb interactions in Na$_x$CoO$_2$. We consider the electron-phonon coupling and the Coulomb interactions, and determine $T_c$ for s-wave superconductivity by solving the linearized Eliashberg equation. When we consider shear phonons as well as breathing phonons, $T_c$ is enhanced by Suhl-Kondo (SK) mechanism. Since SK

Hiroshi Kontani, Masanori Ohno

We study a Hubbard model with a strong onsite impurity potential based on an improved fluctuation-exchange (FLEX) approximation, which we call the GVI-FLEX method. We find that (i) both local and staggered susceptibilities are strongly enhanced around the impurity. By this reason, (ii) the quasiparticle lifetime as well as the local density of states (DOS) a

Lev P. Gor&#39;kov, Gregory B. Teitel&#39;baum

The Hall coefficient data for cuprates show that number of carriers exceeds external doping $x$ at higher $x$ and varies with temperature. Hence, spins on the Cu-sites are not conserved. Activation energy for thermally excited carriers equals the energy between the Fermi surface &#34;arc&#34; and the band bottom near the van Hove singularities. Crossover fro

Vassiliy Lubchenko

Melting is analyzed dynamically as a problem of localization at a liquid-solid interface. A Lindemann-like criterion of melting is derived in terms of particular vibrational amplitudes, which turn out to equal a universal quotient (about one-tenth) of the molecular spacing, at the interface. The near universality of the Lindemann ratio apparently arises owin

Yoshihiro Nishiyama

Extending the parameter space of the three-dimensional (d=3) Ising model, we search for a regime of eliminated corrections to finite-size scaling. For that purpose, we consider a real-space renormalization group (RSRG) with respect to a couple of clusters simulated with the transfer-matrix (TM) method. Imposing a criterion of &#34;scale invariance,&#34; we d

Su Min Tang, Shuang Nan Zhang

The prompt optical emission contemporaneous with the $γ$-rays from $γ$-ray bursts (GRBs) carries important information on the central engine and explosion mechanism. We study the time lag between prompt optical emission and $γ$-rays in GRB 990123 and GRB 041219a, which are the only two GRBs had been detected at optical wavelengths during the ascending burst