Computations in Science Seminars
Jan 2015
7
Wed 12:15
Henry Cohn, Microsoft
e-mail:
Host: Leo Kadanoff ()
Organizer: Ivo Peters ()
Can intricate structure occur by accident?

Many problems in science and engineering involve a delicate interplay between order and disorder. For example, this plays an important role in the study of ground states of interacting particle systems, as well as related problems such as designing error-correcting codes for noisy communication channels. Some solutions of these optimization problems exhibit beautiful long-range order while others are amorphous, and finding a clear basis for this dichotomy is a fundamental mathematical problem. It's natural to assume that any occurrence of dramatic structure must happen for a good reason, but is that really true? In this talk, I'll describe several examples of particle systems and codes showing disparate phenomena (without assuming any specialized background on the part of the audience). The strangest will be some codes Abhinav Kumar, Greg Minton, and I recently found. Although they are highly structured, they seemingly exist just because they can: a parameter count allows them to exist, and they take advantage of this possibility with no evidence of any deeper reason or regularity. They thus form an intriguing test case for order vs. disorder.

Jan 2015
14
Wed 12:15
Osvanny Ramos, University Claude Bernard Lyon 1
e-mail:
Host: Heinrich Jaeger
Organizer: Sayantan Majumdar ()
Predicting scale-invariant events in granular systems

In the last decades granular materials have been used as physical models of complex phenomena: Jamming transition, Self-organized Criticality, Earthquakes, etc. I will present two granular experiments aiming the prediction of large events in a dynamics of power-law distributed avalanches. The first one is a sandpile experiment where an increase of disorder in the internal structure of the system serves as a precursor of large and very large avalanches. The second experiment mimics the behavior of a tectonic fault. It shears continuously a compressed granular layer and uses acoustics as the main source of information.

Jan 2015
21
Wed 12:15
Mary Silber , Northwestern University
e-mail:
Host: William Irvine ()
Jan 2015
28
Wed 12:15
Seth Lloyd, MIT
e-mail:
Host: Leo Kadanoff ()
Quantum algorithms for machine learning and big data analysis

Machine-learning tasks frequently involve problems of manipulating and classifying large numbers of vectors in high-dimensional spaces. Quantum computers are good at manipulating high-dimensional vectors in large tensor product spaces. This talk shows how quantum computers can provide an exponential speed-up over their classical counterparts for a variety of problems in machine learning and big data analysis.

Feb 2015
4
Wed 12:15
Zheng-Tian Lu, Argonne
Host: Daniel Holz ()
Atom Trap, Krypton-81, and Global Groundwater

The long-lived noble-gas isotope 81Kr is the ideal tracer for water and ice with ages of 10^5 – 10^6 years, a range beyond the reach of 14C. 81Kr-dating, a concept pursued over the past five decades by numerous laboratories employing a variety of techniques, is finally available to the earth science community at large. This is made possible by the development of the Atom Trap Trace Analysis (ATTA) method, in which individual atoms of the desired isotope are captured and detected. ATTA possesses superior selectivity, and is thus far used to analyze the environmental radioactive isotopes 81Kr, 85Kr, and 39Ar, These three isotopes have extremely low isotopic abundances in the range of 10^-16 to 10^-11, and cover a wide range of ages and applications. In collaboration with earth scientists, we are dating groundwater and mapping its flow in major aquifers around the world. We have also demonstrated for the first time 81Kr-dating of old ice.

Feb 2015
11
Wed 12:15
Giulia Galli, University of Chicago
e-mail:
Host: Leo Kadanoff ()
Feb 2015
18
Wed 12:15
Heinrich Jaeger, University of Chicago
e-mail:
Host: Leo Kadanoff ()
Feb 2015
25
Wed 12:15
OPEN
Mar 2015
4
Wed 12:15
OPEN
Mar 2015
11
Wed 12:15
OPEN
Mar 2015
18
Wed 12:15
OPEN
Mar 2015
25
Wed 12:15
Daniel Koll, University of Chicago
e-mail:
Host: Wendy Zhang ()
Deciphering the atmospheres of terrestrial exoplanets
Apr 2015
1
Wed 12:15
Andrea Bertozzi, UCLA
e-mail:
Host: Leo Kadanoff ()
Apr 2015
8
Wed 12:15
Emmanuel Villermaux, Institut Universitaire de France
e-mail:
Host: William Irvine ()
Apr 2015
15
Wed 12:15
Michael Brenner, Harvard
e-mail:
Host: Leo Kadanoff ()
Apr 2015
22
Wed 12:15
Joseph Vallino, Marine Biological Labortory
e-mail:
Host: Leo Kadanoff ()
Apr 2015
29
Wed 12:15
Michael Rubenstein, Harvard
e-mail:
Host: Leo Kadanoff ()
May 2015
6
Wed 12:15
Tim Sanchez, Harvard
e-mail:
Host: Leo Kadanoff ()
May 2015
13
Wed 12:15
Luis Bettencourt, Santa Fe Institute
e-mail:
Host: Daniel Holz ()
May 2015
20
Wed 12:15
OPEN
May 2015
27
Wed 12:15
OPEN
Jun 2015
3
Wed 12:15
Alisa Bokulich, Boston University
e-mail:
Host: Leo Kadanoff ()
Jun 2015
10
Wed 12:15
OPEN
Jun 2015
17
Wed 12:15
OPEN
Jun 2015
24
Wed 12:15
OPEN