The Permanents of Gaussian Matrices

Scott Aaronson
Massachusetts Institute of Technology
November 29, 2010

In recent joint work with Alex Arkhipov, we proposed a quantum optics experiment, which would sample from a probability distribution that we believe cannot be sampled (even approximately) by any efficient classical algorithm, unless the polynomial hierarchy collapses. Several optics groups are already working toward doing our experiment.

(Some) Generic Properties of (Some) Infinite Groups

Igor Rivin
Temple University; Member, School of Mathematics
November 29, 2010

This talk will be a biased survey of recent work on various properties of elements of infinite groups, which can be shown to hold with high probability once the elements are sampled from a large enough subset of the group (examples of groups: linear groups over the integers, free groups, hyperbolic groups, mapping class groups, automorphism groups of free groups . . . )

Self-Correction, Distance Estimation and Local Testing of Codes

Dana Moshkovitz
Massachusetts Institute of Technology
November 29, 2010

We construct linear codes of almost-linear length and linear distance that can be locally self-corrected on average from a constant number of queries:

1. Given oracle access to a word $w\in\Sigma^n$ that is at least $\varepsilon$-close to a codeword $c$, and an index $i\in [n]$ to correct, with high probability over $i$ and over the internal randomness, the local algorithm returns a list of possible corrections that contains $c_i$.

Modularity of Galois Representations

Chandrashekhar Khare
University of California, Los Angeles
November 22, 2010

In this expository talk, I will outline a plausible story of how the study of congruences between modular forms of Serre and Swinnerton-Dyer, which was inspired by Ramanujan's celebrated congruences for his tau-function, led to the formulation of Serre's modularity conjecture. I will give some hints of the ideas used in its proof given in joint work with J-P. Wintenberger. I will end by pointing out just one of the many interesting obstructions to generalising the strategy of the proof to get modularity results in more general situations.

Human-Made Climate Change: A Moral, Political, and Legal Issue

James E. Hansen
Columbia University
November 19, 2010

Observations of ongoing climate change, paleoclimate data, and climate simulations concur: human-made greenhouse gases have set Earth on a path to climate change with potentially dangerous consequences for humanity. James Hansen, climatologist and Adjunct Professor in the Department of Earth and Environmental Sciences at Columbia University, explains the urgency of the situation and discusses why he believes it is a moral issue that pits the rich and powerful against the young and unborn, against the defenseless, and against nature. He explores available options to avoid morally unacceptable consequences.