No Arabic abstract
We consider the three dimensional array $mathcal{A} = {a_{i,j,k}}_{1le i,j,k le n}$, with $a_{i,j,k} in [0,1]$, and the two random statistics $T_{1}:= sum_{i=1}^n sum_{j=1}^n a_{i,j,sigma(i)}$ and $T_{2}:= sum_{i=1}^{n} a_{i,sigma(i),pi(i)}$, where $sigma$ and $pi$ are chosen independently from the set of permutations of ${1,2,ldots,n }.$ These can be viewed as natural three dimensional generalizations of the statistic $T_{3}=sum_{i=1}^{n} a_{i,sigma(i)}$, considered by Hoeffding cite{Hoe51}. Here we give Bernstein type concentration inequalities for $T_{1}$ and $T_{2}$ by extending the argument for concentration of $T_{3}$ by Chatterjee cite{Cha05}.
We are proving a Bernstein type inequality in the shift-invariant spaces of $L_2(R)$.
Consider a parabolic stochastic PDE of the form $partial_t u=frac{1}{2}Delta u + sigma(u)eta$, where $u=u(t,,x)$ for $tge0$ and $xinmathbb{R}^d$, $sigma:mathbb{R}tomathbb{R}$ is Lipschitz continuous and non random, and $eta$ is a centered Gaussian noise that is white in time and colored in space, with a possibly-signed homogeneous spatial correlation function $f$. If, in addition, $u(0)equiv1$, then we prove that, under a mild decay condition on $f$, the process $xmapsto u(t,,x)$ is stationary and ergodic at all times $t>0$. It has been argued that, when coupled with moment estimates, spatial ergodicity of $u$ teaches us about the intermittent nature of the solution to such SPDEs cite{BertiniCancrini1995,KhCBMS}. Our results provide rigorous justification of of such discussions. The proof rests on novel facts about functions of positive type, and on strong localization bounds for comparison of SPDEs.
We establish a sharp moment comparison inequality between an arbitrary negative moment and the second moment for sums of independent uniform random variables, which extends Balls cube slicing inequality.
The Small Ball Inequality is a conjectural lower bound on sums the L-infinity norm of sums of Haar functions supported on dyadic rectangles of a fixed volume in the unit cube. The conjecture is fundamental to questions in discrepancy theory, approximation theory and probability theory. In this article, we concentrate on a special case of the conjecture, and give the best known lower bound in dimension 3, using a conditional expectation argument.
We study the blackbody spectrum from slabs of three-dimensional metallodielectric photonic crystals consisting of gold nanoparticles using an ab initio multiple-scattering method. The spectra are calculated for different photonic-crystal slab thicknesses, particle radii and hosting materials. We find in particular that such crystals exhibit a broadband emission spectrum above a specific cutoff frequency with emissivity of about 90%. The studied photonic crystals can be used as efficient selective emitters and can therefore find application in thermophotovoltaics and sensing.