Holger Dullin

Professor Holger Dullin is Professor of Applied Mathematics in the School of Mathematics and Statistics at the University of Sydney. He earned his PhD in theoretical physics from the University of Bremen, Germany, in 1994, with a dissertation on the energy surfaces of the Kowalewskaya top. Since March 2008, he has held his current position at the University of Sydney, where his office is located in Room 714 of the Carslaw Building. Dullin's research lies at the intersection of mathematics and physics, focusing on Hamiltonian dynamical systems. His academic interests encompass the topology of integrable systems, including action-angle variables, Hamiltonian monodromy, semiclassical quantization, and quantum monodromy; classical mechanics involving N-body problems, rigid body dynamics, non-rigid body dynamics in biomechanics, Poisson structures, and geometric phase; bifurcation theory such as twistless bifurcations and Hamiltonian Hopf bifurcations; dynamics of Hamiltonian maps, symplectic maps, and billiards; symbolic dynamics in ergodic billiards and integrable systems; and Euler equations in fluid dynamics, including stability of equilibria on the torus and global dynamics on the rotating sphere.

Dullin has supervised numerous PhD students at the University of Sydney, including Sean Dawson on relating classical and quantum integrable systems, Diana M.H. Nguyen on integrable systems from separation of variables, Nathan Duignan (2019) on regularisation of simultaneous binary collisions, Joachim Worthington (2017) on stability theory in Euler ideal fluid equations, and William Tong (2015) on coupled rigid body dynamics applied to diving. His key publications include 'Twisting somersault' (2016, SIAM Journal on Applied Dynamical Systems, with W. Tong), 'Monodromy in prolate spheroidal harmonics' (2021, Studies in Applied Mathematics, with S. Dawson and D.M.H. Nguyen), 'Symmetry reduction of the 3-body problem in R4' (2020, Journal of Geometric Mechanics, with J. Scheurle), 'An Evans function for the linearised 2D Euler equations using Hill's determinant' (2021, preprint, with R. Marangell), and 'Poisson structure of the three-dimensional Euler equations in Fourier space' (2019, Journal of Physics A: Mathematical and Theoretical, with J.D. Meiss and J. Worthington). He delivers public lectures, such as 'The mathematics of twisting somersaults' in 2023, and teaches courses including MATH3977 Lagrangian and Hamiltonian Dynamics and MATH3063 Nonlinear ODEs and Applications.

Professional Email: holger.dullin@sydney.edu.au