I was utterly unprepared for the devastating news: Erik Matthew Bollt passed away suddenly on December 7, 2025, while cross-country skiing in Higley Flow State Park. He was 58 (Fig. 1).
Figure 1. Erik M. Bollt.
His passing appears to have been due to a heart attack—a shocking conclusion for a man who was as strong as an ox. He was strong, yet exceptionally kind; truly one of the nicest persons I have ever had the privilege to know. Besides skiing, Erik loved to fly small airplanes, sometimes solo and sometimes with his sons (Fig. 2).
Figure 2. Erik, an amateur pilot.
Born on April 24, 1967 and grew up in Bethesda, MD, Erik earned his B.A. in 1990 from the University of California, Berkeley, CA, and his M.S. in 1992 from the University of Colorado, Boulder, CO, both in Applied Mathematics.
Our paths converged through a shared research interest: chaos control. This was the focus of my own work in the early 1990s and the central theme of Erik's Ph.D. dissertation, "Controlling Chaos, Targeting, and Transport", which he completed in 1995, also in Applied Mathematics, at the University of Colorado, Boulder, CO.
In 1998, while he was an Assistant Professor at the United States Naval Academy in Annapolis, MD, Erik invited me to deliver a seminar on "Control and Anti-Control of Chaos" in his mathematics department on October 29. He generously hosted me in his home, where I had the pleasure of meeting his lovely wife, Elizabeth, and their three young sons: Keith, Scott, and Adam.
After I moved from the University of Houston, TX, to assume a chair professorship at the City University of Hong Kong in 2000, Erik sent me a manuscript titled "A New and Simple Chaos Toy." I recommended it to the International Journal of Bifurcation and Chaos, which was published in 2002, featuring an electromechanical model (Fig. 3a). Inspired by his work, my lab at the Centre for Chaos Control and Synchronization (now the Centre for Complexity and Complex Networks) at City University of Hong Kong built its own version, which I named the "Chaotic Bollt Wheel" (Fig. 3b).
Figure 3. The chaotic Bollt wheel.
Erik was promoted to Full Professor in the Department of Mathematics and Computer Science at Clarkson University in Potsdam, NY, in 2006—a promotion he highly deserved and successfully attained. In 2010, he was conferred the W. Jon Harrington Professor of Mathematics.
Upon my appointment as Editor-in-Chief of the International Journal of Bifurcation and Chaos in 2010, I immediately invited Erik to serve as an Associate Editor. He dedicated himself to this role with great responsibility for eight years and later served on the editorial boards of several other journals, including CHAOS, Entropy, and Complexity.
His research record was, needless to say, both prolific and exceptional. In his own words:
"My specialty field is Chaos Theory and Dynamical Systems. I do research in Control of Chaos, Time-Series Embedding Analysis, Frobenius-Perron Operators, Stochastic Dynamical Systems and noise-induced transport mechanisms, Hamiltonian Dynamics, Symbolic Dynamics, Celestial Mechanics, and Communicating with Chaos. In particular, I have recently been working on how noise and determinism interact to create complicated motions. I have also been working lately on information-theoretic questions such as lossless image compression as well as pattern (facial) recognition via support vector machines and kernel learning. I am very interested in networks. I am interested in problems of model reduction, sensing, and predicting bursting."
He authored over 250 publications, including 10 research papers in 2025 alone. His work has garnered more than ten-thousand citations, with an H-index of 49 according to Google Scholar. His research also secured millions of dollars in national grants for Clarkson University and its community.
A complimentary copy of his 2013 book, Applied and Computational Measurable Dynamics, published by the Society for Industrial and Applied Mathematics, still sits on my office bookshelf—a cherished reminder of his personal intellect and scientific contributions (Fig. 4).
Figure 4. Erik's book on my office bookshelf.
We kept in touch over the years, our communication consistent if not frequent, continuing until very recently. Now, with profound sorrow, that conversation has come to an end. With all my heart, I miss Erik deeply.