Articles

06/15/2006-- 06/15/2006

Modelling V838 Monocerotis as a Mergeburst Object

We discuss the main observational facts on the eruption of V838 Monocerotis in terms of possible outburst mechanisms. We conclude that the stellar merger scenario is the only one, which can consistently explain the observations.
Noam Soker Romuald Tylenda
03/18/2007-- 03/18/2007

Further Indications Against Jet Rotation in Young Stellar Objects

I discuss recent observations of asymmetries in Doppler shifts across T Tauri jets, and argue that the observed asymmetric velocity shifts and gradients do not indicate jet rotation. These observations, therefor, cannot be used as a support of a magnetized disk wind. The interaction of the jets with a twisted-tilted (wrapped) accretion disk (or the variable velocity precessing model) accounts better for the observations.
Noam Soker
05/24/2000-- 05/14/2000

Explicit towers of Drinfeld modular curves

We give explicit equations for the simplest towers of Drinfeld modular curves over any finite field, and observe that they coincide with the asymptotically optimal towers of curves constructed by Garcia and Stichtenoth.
Noam D. Elkies
01/18/2001-- 09/10/2000

Blocks of Lie Superalgebras of Type W(n)

We calculate the blocks of the category of finite-dimensional representations of W(0,n), with n > 2, and show that all are of wild type. As an application, we show that the centre of the universal enveloping algebra is trivial.
Noam Shomron
06/13/2001-- 12/10/2000

The Diameter of Long-Range Percolation Clusters on Finite Cycles

Bounds for the diameter and for the expansion of long-range percolation clusters on the cycle $\Z / N\Z$ are given.
Itai Benjamini Noam Berger
08/05/2003-- 08/05/2003

Still better nonlinear codes from modular curves

We give a new construction of nonlinear error-correcting codes over suitable finite fields k from the geometry of modular curves with many rational points over k, combining two recent improvements on Goppa's construction. The resulting codes are asymptotically the best currently known.
Noam D. Elkies
09/01/2004-- 09/01/2004

A lower bound for the chemical distance in sparse long-range percolation models

We consider long-range percolation in dimension $d\geq 1$, where distinct sites $x$ and $y$ are connected with probability $p_{x,y}\in[0,1]$. Assuming that $p_{x,y}$ is translation invariant and that $p_{x,y}=\|x-y\|^{-s+o(1)}$ with $s>2d$, we show that the graph distance is at least linear with the Euclidean distance.
Noam Berger
04/04/2006-- 01/05/2006

Models of real-valued measurability

Solovay's random-real forcing (1971) is the standard way of producing real-valued measurable cardinals. Following questions of Fremlin, by giving a new construction, we show that there are combinatorial, measure-theoretic properties of Solovay's model that do not follow from the existence of real-valued measurability.
Sakaé Fuchino Noam Greenberg Saharon Shelah
03/07/2005-- 07/13/2004

Bell's Theorem - Why Inequalities, Correlations?

It is shown that Bell's counterfactuals admit joint quasiprobability distributions (i.e. joint distributions exist, but may not be non-negative). A necessary and sufficient condition for the existence among them of a true probability distribution (i.e. no-nnegative) is Bell's inequalities. This, in turn, is a necessary condition for the existence of local hidden variables. The treatment is amenable to generalization to examples of 'nonlocality without inequalities'.
Noam Erez
02/07/2006-- 10/17/2005

Teleportation from a Projection Operator Point of View

The process of quantum state teleportation is described from the point of view of the properties of projections onto one-dimensional subspaces. It is introduced as a generalization of the remote preparation of a known state by use of an EPR pair. The discrete and continuous cases are treated in a unified way. The conceptual and calculational simplicity is pedagogically advantageous.
Noam Erez


with thanks to arxiv.org/