Georgia Institute of Technology College of Sciences

In the transition from mathematical billiards to physical billiards, where a ball goes from being a point particle to having a positive radius, it may seem intuitive to assume that no categorical difference exists between the two. A new proof-of-concept paper by Leonid Bunimovich says otherwise. Bunimovich discovered as the radius of a physical billiard ball increases, the change in the behavior of the entire system is equivalent to modeling mathematical billiards with a smaller table. With increasing radius, the geometry of the system evolves. For instance, some parts of the table may become inaccessible to the ball. This results in a progression in the dynamics of the system between mathematical and physical cases, and it may become more or less chaotic with changing radius.

An exceprt from the article in Scilight https://aip.scitation.org/doi/10.1063/1.5128222 

In the transition from mathematical billiards to physical billiards, where a ball goes from being a point particle to having a positive radius, it may seem intuitive to assume that no categorical difference exists between the two. A new proof-of-concept paper by Leonid Bunimovich says otherwise.

Bunimovich discovered as the radius of a physical billiard ball increases, the change in the behavior of the entire system is equivalent to modeling mathematical billiards with a smaller table. With increasing radius, the geometry of the system evolves. For instance, some parts of the table may become inaccessible to the ball. This results in a progression in the dynamics of the system between mathematical and physical cases, and it may become more or less chaotic with changing radius.

“Anything is possible,” said Bunimovich. “There are various types of transitions from order to chaos, and chaos to order.”

Article: “Physical versus mathematical billiards: From regular dynamics to chaos and back,” by L. A. Bunimovich, Chaos (2019). The article can be accessed at https://doi.org/10.1063/1.5122195.

Editor's Note: This story by Maureen Downey in the Atlantic Journal Constitution was originally published on Aug. 15, 2019. It is reposted here with permission.

As a child in New Mexico, Lew Lefton, Georgia Tech associate vice president for research computing, had two passions, math and comedy. Until sixth grade, he never understood mathematics could be a career, figuring mathematicians were akin to blacksmiths, useful in the past, but not relevant today.

His decision to pursue advanced studies in math led to a breakup of sorts where he says he put comedy in the friend zone. “I liked comedy, but I would never consider her for a career,” said Lefton.

Then, in 1988, a postdoc mentor at the University of California, Riverside, asked Lefton to entertain an audience of academics with math jokes. He said he had them laughing their elbow patches off. The romance rekindled and Lefton decided he could manage both. “I had a niche sewn up — mathematician and comedian. He is funny, and he can prove it,” he said.

In New Orleans, where both he and his mathematician wife Enid Steinbart taught at the University of New Orleans, Lefton found himself writing more jokes than equations. Lefton’s comedy and improv career took off, and he worked regularly with other local comics who would go on to successful careers in show business, including physician Ken Jeong.

But the demands of nightly appearances and weekends didn’t mesh with a college teaching career, three children and a busy spouse. Georgia Tech offered positions to both Lefton and Steinbart in 1999. 

At Tech, Lefton has found ways to integrate his interests. In addition to leading research computing, he teaches a computational approach to humor and helps other professors weave humor into their instruction through such Atlanta performance events as Science Riot and Geekapalooza.

While Lefton’s research publications include “Resonance and quasilinear parabolic partial differential equations,” he also co-authored papers on “Humor applied to STEM education” and “Improvisation methods to catalyze engineering creativity.”

He co-leads Tech’s Humor Genome Project, which he describes as Big Data for Humor. Housed in Tech’s Vertically Integrated Projects, where the emphasis is research and development, students investigate various techniques of data analytics and learn about cognitive theories of humor.

“Humor is a challenge for artificial intelligence,” said Lefton. “Is there something humans can do that computers can’t do? Humor appears to be one example.”

Lefton expects his students to learn how to gather and harness data, but there’s the added benefit students get through looking at funny stuff. “Humor helps people who are feeling depressed, not just watching humor but creating jokes,” he said. “Laughing creates social bonds that can help in stressful times. And college is a stressful time for lot of students.”

Lefton’s co-teacher in the project is fellow Tech faculty member Pete Ludovice, an MIT-educated chemical engineer who also performs comedy. Ludovice’s material often targets engineers. He jokes that Tech undergrad engineering majors “use the engineer’s preferred method of birth control — our personalities.”

Scientists doing stand-up is not as rare as it may seem. At the Atlanta Science Festival in March, Lefton and Ludovice served as emcees as nine academics made their comedy debuts. (Material was pegged as suitable for mathematically mature audiences.)

Georgia Tech microbiology professor Brian Hammer discussed fecal microbial transfers, or poop transplants. Hammer began with a lively account of the importance of gut germs, explaining their critical role in protecting the body from “the riffraff, the pathogens, the bad guys.” This was probably one of the few times an audience cheered for diarrhea. Emory biochemistry doctoral student Julia de Amorim talked about being a vegan, “saving the planet one canned chickpea salad at a time, with every almond milk latte, hold the whip.”

Lefton’s wryness is not unnoticed at Tech, where he has been dispatched to deliver the bad news about lottery odds to TV and radio audiences. When the lottery pot surpassed a billion dollars, Lefton informed Atlantans about the unlikelihood of hitting all six numbers. “You are not going to win the lottery. It’s not your fault. It’s the numbers...But you should play anyway because $2 is a great price for a dream.”

He’s also known at Tech for his April Fools’ pranks, including last year’s announcement that Georgia Tech would be the first major research university to have an AI graduate with an accredited degree. “In fact, TutorBot 3.1 will be awarded 44 of the 45 available Bachelor of Science degrees this May,” stated the release. In 2016, Lefton spoofed a poster of the new Georgia Tech Green with one for a “new math building,” which promised “an infinite number of power outlets, each one is only half as large as the previous one, a cafe with a coffee IV and 3.14 flavors of pie, and a mathematical makerspace with 2D plotters, 3D printers, and 4D time machines.”

Lefton’s 2013 April Fools’ missive revealed a new survey on the Tech mascot showing the campus about split on keeping Buzz or replacing it with an “actual yellow jacket, genetically engineered to be 5′ 4″ tall.”

From the review:

The wonderful book by Auffinger, Damron, and Hanson pro- vides an up-to-date and thorough discussion of one of the most classical models in probability theory. The book is readable and user friendly, yet provides the reader with detailed proofs and intuition for classical and modern results. It is therefore an excellent source for an advanced course on the subject. In addition, the book contains dozens of open questions, and it is thus a natural tool for researchers who are interested in the subject.

The September issue of the Notices of the AMS featured Dan Margalit and Prasad Tetali who are running to serve on two AMS committees: https://www.ams.org/journals/notices/201908/201908FullIssue.pdf

• Dan Margalit is a candidate for a Member at Large of the Council.
• Prasad Tetali is a candidate for the Nomination Committee.

Voting is due by Nov. 1, 2019.

Please join me in congratulating Greg Blekherman, who has been selected to receive a 2019 College of Sciences Cullen-Peck Scholar Award in recognition of his innovative research.   Additional information on the award is below, with further details soon to appear on the College of Science news feed. Greg is in good company with past School recipients of this award, including Jen Hom, Anton Leykin and Sung Ha Kang .

Cullen-Peck Scholar Awards: These awards recognize innovative research led by College of Sciences faculty who are at the associate professor or advanced assistant professor level. They are made possible through the generosity of alumni couple Frank Cullen (BS ’73 Math, MS ’76 ISyE, PhD ’84 ISyE) and Libby Peck (BS ’75 Math, MS ’76 ISyE), who wish to recognize and support faculty development within the College of Sciences.

From The Combinatorics and More Section

https://gilkalai.wordpress.com/2019/08/28/mohammad-ghomi-and-joel-spruck-settled-the-cartan-hadamard-conjecture/

Congratulations go to Christine Heitsch, who has been awarded a 2019 College of Sciences Faculty Mentor Award. The College and its ADVANCE Professor jointly established this award to recognize the efforts and achievements of our colleagues in helping guide junior faculty through informal consultation, shared experiences, or advice and encouragement. This award recognizes the important contributions made in the School of Mathematics which help the next generations of faculty succeed.

Note that Christine continues our strong tradition in the School in this area, as observed in the list of past recipients below (including herself). 

Past recipients include:

Shui-Nee Chow (Mathematics),

Jennifer Curtis (Physics),

Luca Dieci (Mathematics),

John Etnyre (Mathematics),

Facundo Fernandez (Chemistry & Biochemistry),

Christine Heitsch (Mathematics),

Rigoberto Hernandez (Chemistry & Biochemistry),

Wendy Kelly (Chemistry & Biochemistry),

Joel Kosta (Biological Sciences),

Raquel Lieberman (Chemistry & Biochemistry),

Ronghua Pan (Mathematics),

Rodney Weber (Earth & Atmospheric Sciences),

Brett Wick (Mathematics),

Haomin Zhou (Mathematics).

The conference "Harmonic Analysis and related topics" which will take place on May 25-29, 2020 at Centre de Recerca Matemàtica (CRM), Barcelona will be dedicated to Michael Lacey's 60th birthday.

Planned activities include time for discussions and collaborations, and a poster session. Christoph Thiele will deliver a Clay Lecture in the program of this conference. 

Funding may be available.

All the updates about the conference (funding, schedule, registration etc) will appear online at the conference website:

 http://people.math.gatech.edu/~glivshyts6/Lacey-conference.html

The current list of speakers:

Alex Iosevich, University of Rochester
Amalia Culiuc, Amherst College
Andrei Lerner, Bar-Ilan University
Ben Krause, California Institute of Technology
Betsy Stovall, University of Wisconsin-Madison
Brett Wick, Washington University St. Louis
Christoph Thiele, HCM Bonn
Irina Holmes, Michigan State University
Francesco Di Plinio, Washington University Saint Louis
Jill Pipher, Brown University
Laura Cladek, UCLA
Lillian Pierce, Duke University
Tuomas Hytonen, University of Helsinki
Svitlana Mayboroda, University of Minnesota
Vladimir Temlyakov, University of South Carolina
Yumeng Ou, Baruch CUNY

The organizers:
Dario Alberto Mena Arias, Universidad de Costa Rica dario.menaarias@ucr.ac.cr
Dmitriy Bilyk, University of Minnesota dbilyk@math.umn.edu
Galyna Livshyts, Georgia Institute of Technology glivshyts6@math.gatech.edu
Ioannis Parissis, University of the Basque Country ioannis.parissis@gmail.com
Maria del Carmen Reguera Rodriguez, University of Birmingham M.Reguera@bham.ac.uk
Sergey Tikhonov, Centre de Recerca Matemàtica (CRM) tikhonov.work@gmail.com

Read the full story on the AJC website

https://www.ajc.com/blog/get-schooled/fun-with-numbers-georgia-tech-prof-writes-equations-and-jokes/0bAzsfdAx3g52w9qbnSsDO/