# Faculty News Briefs

### January 2013

Professor Rob Kusner spoke about "Critical Links and Unlinks" at the Isaac Newton Institute on December 5, 2012. At TU Darmstadt on December 17, he gave an informal seminar about his discovery of the first example of an unlink which is a local (but not global) minimum for ropelength.

Rob Kusner's recent collaboration with experimental physicists at the University of Colorado and theoretical physicists at the University of Pennsylvania resulted in an article to be published in the 10 January 2013 issue of Nature (and online 23 December 2012: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11710.html). Their work explains the complex patterns observed in 3-dimensional liquid crystals and is expected to lead to new materials that can be actively controlled. A press release prepared by the news offices of the three universities involved describes the significance of their work: http://phys.org/news/2012-12-liquid-crystal-future-applications-advance.html.

On December 12, 2012 Professor Michael Lavine attended a speed-dating event at Amherst College designed to match biologists and mathematicians with similar research interests. The Department conducted five interviews for a position in Topology and had its holiday party.

The paper "Entropic fluctuations in statistical mechanics: I. Classical dynamical systems" by Vojkan Jaksic, Claude-Alain Pillet, and Professor Luc Rey-Bellet belongs to the "Highly Downloaded Collection 2011" from the journal Nonlinearity. See http://iopscience.iop.org/0951-7715/page/Highly%20Downloaded%20Collection%202011 for more details.

Luc Rey-Bellet has been invited to join the editorial board of the Journal of Statistical Physics for the period 2013-2015. The Journal of Statistical Physics publishes original papers, review papers, and book reviews in all areas of statistical physics as well as in related fields concerned with collective phenomena in physical systems. It was founded in 1969 and is the leading journal in the field of statistical mechanics.

### December 2012

Professor Rob Kusner had a busy November abroad. On the 6th & 7th, Rob visited the University of Bristol, where he offered an extended lecture on "A Scattering Theory of Soap Bubbles" to their Theoretical Physics seminar. The following two days he visited the University of Wales in Aberystwyth, where he delivered a colloquium version of the soap-bubble-scattering talk and another seminar on applying meromorphic differentials to mathematical problems arising in materials science (smectics, tilings, and the like). On the 15th &16th, Rob was at the University of Warwick Maths Institute, where he lectured on the "Space of Soap Bubbles" in their Geometric Analysis seminar. He also said hello to former UMass Ph.D. student, Dmitriy Rumynin, who is an Associate Professor there now. On the 20th Rob was back at the Isaac Newton Institute in Cambridge and gave a "Space of Soap Bubbles" seminar in the Topological Dynamics Programme there, relating what might be called "Newton's Laws of Bubble Scattering" to the basic mathematical theorems in the field of constant mean curvature surfaces. Rob adapted this theme as his Kings College London colloquium lecture on the 23rd and in his lead-off plenary lecture at a workshop on "Geometric Structures in PDE" at the ICMat research center in Madrid, Spain, on the 27th. Finally, Rob served as "El Presidente" of a Ph.D. panel at the Universidad Autonoma de Madrid on the 29th. Rob had also been the First Reader of the dissertation.

On November 13, 2012 Professor John Staudenmayer gave an invited talk "Estimating Physical Activity with an Accelerometer: An Overview of Methods" at the 16th Congress of the Latin American Nutrition Society in Havana, Cuba.

Professor Emeritus Floyd Williams gave an invited colloquium talk at Idaho State University on November 2, 2012. The title of the talk was "Fourier Analysis, Scattering, and Mock Zeta Function of Certain Black Hole Vacua."

### November 2012

On October 8, 2012 Visiting Assistant Professor Christopher Chong gave at talk in the Applied Math and PDE Seminar at Drexel University in Philadelphia, PA. The title of the talk was "Modulation Equations in Nonlinear Lattices."

While in the UK this fall, Professor Rob Kusner lectured on "Chirality for Curves (and More)" at the International Center for Mathematical Sciences workshop on Tangled Fields in Edinburgh, Scotland during the week of October 16-20, 2012. Rob also gave the October 25 geometric analysis seminar at Imperial College London on "The Space of Soap Bubbles."

During the period November 11-16, 2012 Postdoctoral Research Associate Yannis Pantazis participated in the workshop Nonequilibrium Statistical Mechanics: Mathematical Understanding and Numerical Simulation, held in Banff International Research Station in Alberta, Canada. He presented a talk titled "Applications of Entropy Production and of Relative Entropy."

On October 14, 2012 Visiting Assistant Professor Pengfei Zhang gave a talk at Penn State University at the Semi-annual Workshop in Dynamical Systems and Related Topics. The talk was titled "Volume of the Set of Transitive Points of Partially Hyperbolic Diffeomorphisms."

### October 2012

Professor George Avrunin received the College of Natural Sciences Outstanding Service and Outreach Award, along with Alexander Schreyer from the Department of Environmental Conservation. This award was announced at the State of the College session on September 4, 2012; the formal presentation will take place at a later event.

On September 24, 2012 Professor Matthew Dobson gave a talk titled "A Langevin Dynamics for Systems Immersed in a Linear, Nonequilibrium Flow" at IWCCM 2012 (International Workshop on Computational Mechanics of Materials).

The book by Professor Richard S. Ellis, Blinding Pain, Simple Truth: Changing Your Life Through Buddhist Meditation, is the Silver Medal winner in the Self-Help category of the 2012 Florida Publishers Association President's Book Awards. Fifty-four medalists were awarded gold and silver medals in 20 categories on September 29, 2012.

During the period August 20-22, 2012 Professor Krista Gile was part of an Expert Consultation on Respondent-Driven Sampling at the Centers for Disease Control and Prevention in Atlanta, GA.

On September 21, 2012 Professor Rob Kusner gave a seminar about "A Simple Matrix Chirality Invariant for Curves" at the Isaac Newton Institute for Mathematical Sciences in Cambridge, UK. He is visiting there this fall.

Professor Ivan Mirkovic is a member of the editorial boards of Glasnik Matematicki, Journal of Number Theory, Selecta Mathematica, and Transformation Groups. During the summer he attended a conference on Symplectic Algebraic Geometry in Luminy, France and a conference on Infinite Dimensional Lie Algebras in Montreal , Canada. In Montreal he gave a talk titled "Modular Representations and Koszul Diality."

Professor Andrea Nahmod reports on the following activities:

She delivered an invited lecture at the meeting on Evolution Equations, held in honor of Terence Tao's being awarded the Nemmers Prize. The meeting took place at Northwestern University in Evanston IL during the period May 4-6, 2012.

Professor Nahmod gave a talk titled "Almost Sure Existence of Global Weak Solutions for the Supercritical Navier-Stokes Equations" at the meeting on Nonlinear Evolution Problems held at the Oberwolfach Institute of Mathematics in Germany during the period May 13-19, 2012.

Professor Nahmod was the lead organizer and the chair of the Committee for the Conference on Challenges in Analysis, Geometry and Computation: High Dimensional Synthesis. This conference was in honor of Ronald R. Coifman, Peter W. Jones, and Vladimir Rokhlin. It was held at Yale University during the period June 4-6, 2012, and it was funded by grants (co-PI) from NSF, ONR, and Yale University. Between 200 and 250 people participated.

Professor Nahmod was awarded NSF grant DMS-1201443, "New Challenges in Nonlinear PDEs," for the period July 2012 - 2015. She is the principal PI on this grant.

She is a Co-Editor of Recent Advances in Harmonic Analysis and Partial Differential Equations, AMS Contemporary Mathematics Series, Volume 58, August 2012. Also, in February 2012, Professor Nahmod became an Associate Editor of Potential Analysis Journal, which is published by Springer. L. Saloff-Cost is the Editor in Chief.

On August 24, 2012 Allison J. Tanguay, Professor Nahmod's doctoral student at UMass Amherst, defended her Ph.D. thesis titled "New Bilinear Estimates for Quadratic-Derivative Nonlinear Wave Equations in 2+1 dimensions."

Nathan Senecal, Professor Nahmod's Capstone honors student, wrote a thesis on Nonlinear Fourier Analysis and was accepted into several Ph.D. program in mathematics. After narrowing down his choices to Princeton University, University of California at Berkeley, and UCLA, in fall 2012 he entered the Ph.D. program at UCLA, where he will work with Terence Tao.

Derek Wood, Profesor Nahmod's Capstone honors student, wrote a thesis on Nonlinear Dispersive PDEs. In fall 2012 he entered the Ph.D. program at the University of Michigan in Ann Arbor. His final choices were between the latter university and University of Wisconsin in Madison.

The AMS has initiated the Fellows of the American Mathematical Society program, of which the first group will be officially inducted during the Joint Meetings in San Diego, CA in January 2013. Professor Emeritus Floyd Williams was invited to be part of that group, which honors "distinguished contributions to mathematics." Details of the Fellows of the AMS program can be found at http://www.ams.org/profession/ams-fellows.

### September 2012

In July 2012 Professor Tom Braden gave a talk at a conference on Representation Theory and Symplectic Algebraic Geometry at the Centre International de Rencontres Math√©matiques in Marseille, France.

Professor John Buonaccorsi delivered a special invited talk on "Measurement Error in Dynamic Models" at the International Symposium in Statistics (ISS) on Longitudinal Data Analysis Subject to Outliers, Measurement Errors, and/or Missing Values held in St. John's, Newfoundland during the period July 16-18.

Visiting Assistant Professor Christopher Chong was awarded an AMS-Simons Travel Grant for early-career mathematicians in June 2012. Later that month he organized a minisymposium on "Strongly Nonlinear Lattices and Granular Crystals" at the SIAM conference on Nonlinear Waves and Coherent Structures held in Seattle, WA during the period June 13-16. In July he visited the University of Stuttgart in Germany and presented his work on "Dark Breathers in Granular Crystals" on July 2.

Graduate students Elizabeth Drellich and Jennifer Koonz attended a two-week long summer school and conference in Osaka, Japan in July 2012. The conference dealt with all aspects of Schubert calculus, a subject of interest to combinatorialists, algebraic geometers, and representation theorists. A contest was held for the best poster submitted by a graduate student or postdoc, and out of the twenty-five posters submitted, Jennifer Koonz's was the winner. As a prize Jennifer received a "corduroy chalkboard eraser that they assured me would erase really well and a fancy mechanical pencil."

On July 2, 2012 Professor Richard S. Ellis gave a talk in the Mathematics Colloquium in the Department of Mathematics at Bogazi√ßi University in Istanbul, Turkey. The title of his talk was "From Large Deviations to Statistical Mechanics: What Is the Most Likely Way for an Unlikely Event To Happen?" In conjunction with his being an adjunct professor of Judaic Studies at UMass Amherst, during spring 2012 Richard taught an adult education course at the Jewish Community of Amherst titled "Mindfulness of the Torah." The Jenkins Group in Traverse City, MI announced that Richard's book, *Blinding Pain, Simple Truth: Changing Your Life Through Buddhist Meditation*, is the Silver Medal winner in the Meditation/Relaxation category of The 2012 Living Now Book Awards. Ninety-three medalists and 4 Books of the Year were announced on August 23, 2012 in 29 lifestyle categories. Information about the awards is available at this article; Richard's book is listed in category 22.

While a member of the University of California Santa Barbara's Kavli Institute for Theoretical Physics during June and July 2012, Professor Rob Kusner organized the Knotted Fields program. This fall Rob is a Visiting Fellow at the Isaac Newton Institute in Cambridge, England, and a participant in the Topological Dynamics program.

Professor Michael Lavine gave a talk titled "Lessons from Consulting: Three Examples" at the Joint Statistics Meeting in San Diego, CA on August 1, 2012.

Professor Eric Sommers will spend the upcoming year as a program officer at the National Science Foundation in the Division of Mathematical Sciences. He will join three other officers in the Algebra and Number Theory program, which is responsible for grants that the NSF makes in number theory, algebraic geometry, commutative algebra, and representation theory.

Professor Eric Sommers and Professor Emeritus Floyd Williams both gave invited, one-hour talks at a CBMS (Conference Board on Mathematical Sciences) conference held at the University of Massachusetts Boston during the period July 16-20, 2012. The title of the conference was "Unitary Representations of Reductive Groups." Eric's talk was titled "The Singularities of Slices in the Nilpotent Cone, and Floyd's talk was titled "Spectral Sequences: Some Representation-Theoretic Applications."

On May 15, 2012 Professor John Staudenmayer gave an invited talk titled "Estimating Physical Activity with an Accelerometer: An Overview of Methods" in Rome, Italy at the 7th International Conference on Diet and Activity Methods. He was also a faculty member at the NIH Mobile Health Summer Training Institute held at Northeastern University during the period July 29 - August 3, 2012.

Professor Jenia Tevelev gave a mini-course of four lectures titled "Stable Surfaces and Their Moduli Spaces" at the Summer School in Algebraic Geometry held at Sol Beach, South Korea during the period June 25-29, 2012. The summer school was sponsored by the Korea National Research Foundation. Further information is available at this website.

Professor Bruce Turkington participated in the Sixth International Workshop on Non-Equilibrium Thermodynamics and the Third Lars Onsager Symposium, which was held in Roros, Norway from August 20 to 24. He presented a lecture titled "Derivation of the GENERIC Form of Nonequilibrium Thermodynamics from a Statistical Optimization Principle."

Professor HongKun Zhang had a busy summer, during which she gave the following talks:

- A talk on "Diffusive Billiards" at the 9th AIMS Conference on Dynamical Systems held in Orlando on July 3, 2012.
- Three invited talks at the Dynamical System Workshop held in Beijing University during the week of July 16-21. The talks were titled "Introduction to Billiards I, II" and "New Trends in the Study of Chaotic Billiards."
- A colloquium talk on July 24 on "New Trends in Nonequilibrium Billiards" and a talk on "Estimation of Volatility for Option Pricing Models" on July 27, both at Inner Mongolia University.
- A colloquium talk on July 30 on "New Trends in Nonequilibrium Billiards" at Inner Mongolia Industrial University.
- A seminar talk on "New Trends in Nonequilibrium Billiards" on August 23 at the Mathematics Institute of the Chinese Academy of Sciences in Beijing.
- A colloquium talk on "Diffusive Billiards and Their Applications" on August 29 at Houston University.