Madison Chaos and Complex Systems Seminar

Fall 2018 Seminars

All seminars are Tuesday at 12:05 pm in 4274 Chamberlin Hall except as noted. Refreshments will be served.

Short List


September 11, 2018

A brief history of time(keeping): Optical atomic clocks and their applications

Shimon Kolkowitz, UW Department of Physics

Optical atomic clocks are now the most stable and accurate timekeepers in the world, with fractional accuracies equivalent to neither losing nor gaining a second over the entire age of the universe. This unprecedented level of metrological precision offers sensitivity to new physics phenomena, opening the door to exciting and unusual applications. This talk will provide an introduction to how and why time is measured from a historical perspective, with an emphasis on the recent development of optical atomic clocks and their applications. I will discuss recent progress on pushing clocks to even greater levels of precision, as well as prospects for future improvement. Finally, I will give a brief overview of potential future applications of clocks, including gravitational wave detection, tests of general relativity, and searches for physics beyond the Standard Model.

September 18, 2018

Redistricting and randomness

Jordan Ellenberg, UW Department of Mathematics

I will talk about the challenge of providing a useful, robust, and simple measure of “partisan gerrymandering,” the practice of drawing legislative district lines to secure advantage for one political party.  This has been a contentious legal issue for many years, with Wisconsin’s own assembly districts among those which have are in legal jeopardy, and one of the great challenges is to establish protocols which are both legally and mathematically sound.

September 25, 2018

Changes in excellence among United States research universities

 Rogers Hollingsworth, UW Departments of Sociology and History

What are the explanations for changes in excellence in American research universities? The classic answers to this problem were variations on Robert Merton’s elaboration of the “Matthew” effect in science – those who have abundance will accumulate advantage and those who have not will continue to be disadvantaged. Numerous analysts have addressed the Matthew effect when explaining inequality in research excellence among individual scientists as well as universities.

This presentation demonstrates that the Mertonian explanation is not correct when analyzing long-term changes in recognition of excellence among American research universities. It focuses on the considerable instability in the ranking of excellence in the basic biological sciences over many decades. It demonstrates that recognition for excellence of research universities is distributed into six patterns, the analysis and explanation of which is the major focus of the presentation.

It is a small part of the study of changes over many decades in research excellence among universities in France, Great Britain, the United States, and Germany with soft comparisons to universities in Sweden and Japan.

The data for the presentation is based on re-analysis of data collected at various time points by the American Council of Education, the National Research Council, and citation indices by ISI-Thompson Reuters. The data are also based on 596 in-depth interviews of scientists by Hollingsworth in the six named countries over thirty years (some scientists were interviewed on multiple occasions for a total of 913 interviews). See for the names, exact dates, and places of the interviews. Data sources and methodology for rankings are available at

October 2, 2018

Some half-baked philosophy of mathematics

Moe Hirsch, UW Department of Mathematics

I'll discuss what I think are the basic philosophical questions:


(1) What makes math universal? Its results seem independent of time and place. No one doubts Euclid's or Pythagoras' theorems of thousands of years ago, even if we think some of the proofs aren't correct. No one since Hitler and Stalin thinks its correctness depends on race, religion or nationality. But will the same math be found wherever there's life in the universe?

(2) Why is math so useful? Try spending a day without thinking about numbers.

(3) Its results seem absolutely true. But are they? If they are, how can we prove it? And if we can prove it, how do we know our proof is correct?


Essays in Humanistic Mathematics: Mathematical Association of America

What is Mathematics Really? R. Hersh, Oxford University Press

Where Mathematics Comes from: G. Lakoff & R Nunez, Basic Books

The Math Gene: K. Devlin, Basic Books

See a list of quotes from the lecture.

October 9, 2018

Observations concerning forensic and clinical encounters involving children with autism spectrum disorder.

Doug Maynard, UW Department of Sociology

Perceivedly inappropriate social behavior is a central feature of Autism Spectrum Disorder, in that individuals with ASD frequently may violate or breach commonsense norms and expectations. These violations may meet with polite indifference, informal prohibitions, or corrections. Using two forensic cases (police encounters with ASD individuals) and one clinical encounter, I will explore more formal sanctioning and how this can involve something we call “transpositioning.” Under the auspices of official protocols, transpositioning refers to how an official may turn a child’s responsive move into an initiating move, justifying consequential indifference at best or sometimes severe intervention at worst. However, by situating violations in their interactional contexts, we can see how actions usually attributed to the child and his psychological functioning alone are concertedly produced. In group discussion, I hope to have us consider how we can have better understandings of ASD-associated conduct in home, school, and public environments.

October 16, 2018

Renewable energy: A viable path forward

Michael Winokur, UW Department of Physics

The rate of growth in renewable energy production has generally exceeded even the most optimistic projections.   This dramatic  scenario has been driven by a steady stream of technological advancements in combination with a breathtaking reduction in the actual cost of the energy production.   Many traditional sources of energy  are becoming economically uncompetitive.  This introductory level talk  will give a broad overview of the potential sources of renewable energy with an emphasis on the recent history of solar and wind energy production and likely near-term developments which will further improve device performance.  Time permitting some of the issues associated with energy storage will be discussed.

October 23, 2018

The dynamics of mood in bipolar disorder

Amy Cochran, UW Departments of Biostatistics & Medical Informatics

Bipolar disorder is a chronic disease of severe mood fluctuation. Longitudinal patterns are central to any patient description, but are condensed into simple attributes and categories. Although these provide a common language for clinicians, they are not supported by empirical evidence.  In this talk, I will discuss modeling frameworks for providing patient-level descriptions of longitudinal patterns. Since these frameworks often represent competing hypotheses, e.g. mood is periodic or mood has distinct 'states', I will focus on a key question: how to differentiate between models when only time courses of mood are available? Through statistical analysis, we settle on the idea that BP could arise from an inability for mood to quickly return to normal when perturbed and present a model to embody this idea that can be personalized to individual with bipolar disorder. I will conclude by discussing next steps for translating this work into clinical care.

October 30, 2018

Complexity and levels of analysis: more than one required

Tim Allen, UW Department of Botany

A complex system requires more than one level of analysis.  The levels do not map onto one another, and that leads to uncertainty and contradiction.  Complexity arises not from material reality but rather how the observer questions the system.  Multiple levels is a good way to explain complexity to mechanistic reductionists.  I will give examples of complexity in these terms:  Koestler’s holon, Chaos theory, Skeleton as a lever system, Jevons paradox, High and Low gain EROI, Rosen similarity vs similitude, Euclidean vs non-Euclidean space.  Complexity appears in emergence between non-linearity and levels in conflict with privilege denied to any one level.

November 6, 2018

A report on the recent work by Araujo and Liotta on the topological requirements for robust perfect adaptation in networks of any size

Sigurd Angenent, UW Department of Mathematics

From the article, Robustness, and the ability to function and thrive amid changing and unfavorable environments, is a fundamental requirement for living systems. Until now it has been an open question how large and complex biological networks can exhibit robust behaviors, such as perfect adaptation to a variable stimulus, since complexity is generally associated with fragility. Here we report that all networks that exhibit robust perfect adaptation (RPA) to a persistent change in stimulus are decomposable into well-defined modules, of which there exist two distinct classes. These two modular classes represent a topological basis for all RPA-capable networks, and generate the full set of topological realizations of the internal model principle for RPA in complex, self-organizing, evolvable bionetworks. This unexpected result supports the notion that evolutionary processes are empowered by simple and scalable modular design principles that promote robust performance no matter how large or complex the underlying networks become.

November 13, 2018

Artificial general intelligence

Bill Hibbard, UW Space Science and Engineering Center

In the early 1960s Ray Solomonoff combined Turing's theory of computation with Shannon's information theory to create algorithmic information theory. The Kolmogorov complexity of a binary string is defined as the length of the shortest program that computes the string. Solomonoff used a related measure as the basis for an (uncomputable but approximable) universal induction algorithm for predicting arbitrary binary strings. In the early 2000's Marcus Hutter combined this induction algorithm with sequential decision theory to define his universal AI that maximizes expected rewards from arbitrary environments, and to define a formal measure of intelligence. This work led to conferences and journals dedicated to the mathematical study of properties of artificial general intelligence (AGI) systems, including ways that they may fail to conform to the intentions of their designers and ways to design systems that do conform to their design intentions. These problems are not resolved and research is very active. While some mainstream AI developers criticize AGI theory, the creators of some of the most successful AI systems (e.g., Google DeepMind) are also deeply involved in this AGI research. Practical versions of Hutter's universal AI are called Bayesian program learning and in some ways they outperform the deep learning algorithms that are revolutionizing AI.

See the slides in PowerPoint format for this talk.

November 20, 2018

Ergodicity in chaotic oscillators

Clint Sprott, UW Department of Physics

The harmonic oscillator is the simplest and most common nontrivial dynamical system. The prototypical mechanical example is a mass suspended by a spring, but the same dynamics occur in most musical instruments, many electronic devices, models of economic and ecological systems, some chemical reactions, and many other real-world systems. However, most oscillations in nature are not simple but rather exhibit aperiodic fluctuations such as the weather and the stock market. I will describe a new model of a chaotic oscillator whose behavior is identical to a harmonic oscillator in equilibrium with a source of heat at a constant temperature. It represents the culmination of a 30-year search for an elegant chaotic model whose solution is ergodic and whose variables accurately exhibit a normal (Gaussian) distribution as expected for a truly random process.

See the slides in PowerPoint format for this talk.

November 27, 2018

Solar activity and its influence on us

Alex Lazarian, UW Department of Astronomy

The Sun is a magnetically active star. Solar activity results in inducing the solar wind as well as generating the energetic particles. The solar wind affects the size of the heliosphere around the solar system and this induces modulation of the galactic cosmic rays arriving to the Earth. Energetic particles from the Sun interact with the Earth's magnetic field and cause electromagnetic storms. I shall discuss how the Sun affects the Earth ecosystem.

December 4, 2018

Advancing climate science education, inquiry, and literacy across rural Wisconsin communities

Michael Notaro, UW Nelson Institute Center for Climatic Research
Rosalyn Pertzborn, UW Space Science and Engineering Center

Our project, recently funded by the Baldwin Wisconsin Idea Endowment, aims to inspire scientific, placed-based inquiry and advance climate science education and literacy across the economically disadvantaged rural communities of Wisconsin.  The collaborative team synergistically unites the climate change expertise of the UW-Madison Nelson Institute Center for Climatic Research, science education experience of the UW-Madison Atmospheric, Earth, and Space Outreach Program of the Space Science and Engineering Center, and local environmental sustainability focus and extensive volunteer network of the Wisconsin Ice Age Trail Alliance.  We aim to (1) expand understanding of environmental issues by facilitating accessibility to climate researchers; (2) incorporate data collection within the Global Learning and Opportunities to Benefit the Environment (GLOBE) program for comparison of climate phenomena and local environmental impacts; (3) provide teacher/citizen scientist training for GLOBE protocol application at schools; and (4) provide authentic K-12 research experiences by developing GLOBE special measurement protocols in collaboration with climate scientists to facilitate effective community climate change adaptation.  Data collection focuses on a north-south transect of schools along the Wisconsin Ice Age Trail through the sharp climatic and ecological gradients of the Curtis tension zone.  Environmental data collection and analysis will support evidence-based scientific understanding of climate change risks for guiding community decisions on adaptation.

December 11, 2018

Social and economic mobility in an era of extreme inequality; Who owns the robots?  

Tim Smeeding, LaFollette School of Public Affairs and Economics

Americans used to believe that we lived in a land of opportunity with a good chance for everyone and their children to do well. But America is near the bottom of nations where everyone has fair chance of reaching the American Dream. This lecture considers mobility at the bottom, top and middle of the distribution, both over time and across generations in a nation where capital income (who owns the robots) dominates labor income, where public policy increases extreme inequality and where the future of work is increasingly dim for those without a college education and without good opportunities to make use of that investment.

See the slides in PDF format for this talk.