School of Natural Sciences

Gamma Ray Bursts from a Different Angle: The Sequel

David Eichler
Ben Gurion University
September 23, 2014

A classic problem posed by long gamma ray bursts (GRB) is that the energy output requires gravitational energy release so deep within the host star that the prompt gamma rays should, upon naive consideration, have been obscured. It is suggested that photons emitted along the direction of the emitting plasma's motion are indeed geometrically blocked by optically thick baryonic matter, and that we usually see the photons that are emitted nearly backward in the frame of the emitting plasma. Many puzzling observations concerning GRB then fall into place.

What's Next?

Nathan Seiberg
Professor, School of Natural Sciences
December 4, 2013
In recent decades, physicists and astronomers have discovered two beautiful Standard Models, one for the quantum world of extremely short distances, and one for the universe as a whole. Both models have had spectacular success, but there are also strong arguments for new physics beyond these models. In this lecture, Nathan Seiberg, Professor in the School of Natural Sciences, reviews these models, their successes, and their shortfalls.

Loops and Self Reference in Language and Life

Tsvi Tlusty
Weizmann Institute of Science; Member, Simons Center for Systems Biology, IAS
March 6, 2013

We will discuss the notion of loops in linguistic structures, mainly in dictionaries. In a simplified view, a dictionary is a graph that links every word (vertex) to a set of alternative words (the definition) which in turn point to further descendants. Iterating through definitions, one may loop back to the original word. We will examine possible links between such definitional loops and the emergence of new concepts during the evolution of languages. Potential relation to living systems will be briefly discussed.