Elisabeth Werner

Non-additivity of Renyi entropy and Dvoretzky's Theorem (2009)

Aubrun, Guillaume, Szarek, Stanislaw, Werner, Elisabeth

The goal of this note is to show that the analysis of the minimum output p-Renyi entropy of a typical quantum channel essentially amounts to applying Milman's version of Dvoretzky's Theorem about...

Inequalities for mixed $p$-affine surface area (2008)

Werner, Elisabeth, Ye, Deping

We prove new Alexandrov-Fenchel type inequalities and new affine isoperimetric inequalities for mixed $p$-affine surface areas. We introduce a new class of bodies, the illumination surface bodies,...

Uniform estimates for order statistics and Orlicz functions (2008)

Gordon, Yehoram, Litvak, Alexander, Schütt, Carsten, Werner, Elisabeth

We establish uniform estimates for order statistics of sequences of independent identically distributed random variables with log-concave distribution in terms of Orlicz norms associated with the...

N→∞ (2008)

Monika Ludwig, Carsten Schütt, Elisabeth Werner, Main Results

There is a constant c such that for every n ∈ N, there is a Nn so that for every N ≥ Nn there is a polytope P in R n with N vertices and where B n 2 voln(B n 2 △P) ≤ c voln(B n 2 2)N n−1

Approximation of the Euclidean ball by polytopes (2008)

Monika Ludwig, Carsten Schütt, Elisabeth Werner, Main Results

There is a constant c such that for every n N, there is a N n so that for every N with N vertices and where B 2 denotes the Euclidean unit ball of dimension n. # partially supported by a grant from...

New $L_p$ Affine Isoperimetric Inequalities (2007)

Werner, Elisabeth, Ye, Deping

We prove new $L_p$ affine isoperimetric inequalities for all $ p \in [-\infty,1)$. We establish, for all $p\neq -n$, a duality formula which shows that $L_p$ affine surface area of a convex body $K$...

Geometry of sets of quantum maps: a generic positive map acting on a high-dimensional system is not completely positive (2007)

Szarek, Stanislaw J., Werner, Elisabeth, Zyczkowski, Karol

We investigate the set a) of positive, trace preserving maps acting on density matrices of size N, and a sequence of its nested subsets: the sets of maps which are b) decomposable, c) completely...

Approximation of the Euclidean ball by polytopes (2005)

The Erwin, Schrödinger International Boltzmanngasse, Monika Ludwig, Carsten Schütt, Elisabeth Werner, Monika Ludwig, ...

There is a constant c such that for every n ∈ N there is a Nn so that for every N ≥ Nn there is a polytope P in R n with N vertices and voln(B n 2 △P) ≤ c voln(B n 2 2)N n−1 where B n 2...

Orlicz norms of sequences of random variables (2002)

Gordon, Yehoram, Litvak, Alexander, Schütt, Carsten, Werner, Elisabeth

Let $f_{i}$, $i=1,\dots,n$, be copies of a random variable f and let N be an Orlicz function. We show that for every $x\in \mathbb{R}^{n}$ the expectation $\mathbf{E} \| (x_i f_i) _{i=1}^n \|_N $ is...

An Analysis of Completely-Positive Trace-Preserving Maps on 2x2 Matrices (2000)

Ruskai, Mary Beth, Szarek, Stanislaw, Werner, Elisabeth

We give a useful new characterization of the set of all completely positive, trace-preserving (i.e., stochastic) maps from 2x2 matrices to 2x2 matrices. These conditions allow one to easily check any...

One Dimensional Regularizations of the Coulomb Potential with Application to Atoms in Strong Magnetic Fields (1999)

Brummelhuis, Raymond, Ruskai, Mary Beth, Werner, Elisabeth

We consider one-dimensional regularizations of the Coulomb potential formed by taking a two-dimensional expectation of the Coulomb potential with respect to the Landau states. It is well-known that...

Study of a Class of Regularizations of 1/|x| using Gaussian Integrals (1999)

Ruskai, Mary Beth, Werner, Elisabeth

This paper presents a comprehensive study of a class of functions which approximate 1/|x| for large x but which are finite at the origin. These functions arise naturally in the study of atoms in...

On the p-affine surface area (1997)

Meyer, Mathieu, Werner, Elisabeth

We give geometric interpretations of certain affine invariants of convex bodies. The affine invariants are the p-affine surface areas introduced by Lutwak. The geometric interpretations involve...

A pair of optimal inequalities related to the error function (1997)

Ruskai, M. Beth, Werner, Elisabeth

The Error Function \begin{eqnarray} V(x) & \equiv & \sqrt{\pi} e^{x^2} [1 - \hbox{erf}(x)] \\ & = & \int_0^\infty \frac{ e^{-u} }{\sqrt{x^2 + u}} du = 2 e^{x^2}\int_x^\infty e^{-t^2} dt \nonumber...

The Santalo-regions of a convex body (1997)

Meyer, Mathieu, Werner, Elisabeth

Motivated by the Blaschke-Santal\'o inequality, we define for a convex body K in ${\bf R}^n$ and for $t \in {\bf R}$ the Santal\'o-regions S(K,t) of K. We investigate properties of these sets and...

A general geometric construction for affine surface area (1997)

Werner, Elisabeth

Let $K$ be a convex body in ${\bf R}^n$ and $B$ be the Euclidean unit ball in ${\bf R}^n$. We show that $$\mbox{lim}_{t\rightarrow 0} \frac{|K| -|K_t|}{|B| - |B_t|}= \frac{as(K)}{as(B)},$$ where...

Confidence regions for means of multivariate normal distributions and a non-symmetric correlation inequality for gaussian measure (1997)

Szarek, Stanislaw J., Werner, Elisabeth

Let $\mu$ be a Gaussian measure (say, on ${\bf R}^n$) and let $K, L \subset {\bf R}^n$ be such that K is convex, $L$ is a "layer" (i.e. $L = \{x : a \leq < x,u > \leq b \}$ for some $a$, $b \in {\bf...

Confidence Regions For Means Of Multivariate Normal Distributions And A Non-Symmetric Correlation Inequality For Gaussian Measure (1997)

Stanislaw Szarek And, Stanislaw J. Szarek, Elisabeth Werner

. Let ¯ be a Gaussian measure (say, on R n ) and let K;L ` R n be such that K is convex, L is a "layer" (i.e. L = fx : a hx; ui bg for some a, b 2 R and u 2 R n ) and the centers of mass...

A Pair of Optimal Inequalities Related to the Error Function (1997)

Mary Beth Ruskai, Elisabeth Werner

(4) We also show that these inequalities are optimal for functions of the form (4) with equality only at g ß (0) = V (0) = p ß: The bounds in (3) are considerably sharper than the classical...

A Nonsymmetric Correlation Inequality for Gaussian Measure

Szarek, Stanislaw J., Werner, Elisabeth

Let[mu]be a Gaussian measure (say, onRn) and letK,L[subset, double equals]Rnbe such thatKis convex,Lis a "layer" (i.e.,L={x: a[less-than-or-equals, slant][less-than-or-equals, slant]b} for...