Van Saarloos has focused his research on
theoretical physics, in particular in statistical and condensed matter physics. His work in pattern formation in non-equilibrium systems centers on the development of the amplitude equation description of systems exhibiting a transition to standing waves. With Hohenberg he developed a classification of fronts, pulses, sources and sinks in such systems.
Condensed matter and statistical physics Together with his thesis advisor Mazur, van Saarloos calculated the mobility tensors submerged in viscous fluid of an arbitrary number of spheres in an expansion of power series. Their expressions, which involve three- and four particle interactions, provide the basis for many particle hydrodynamic simulations. Van Saarloos' work on propagating fronts on a number of years culminated in a paper together with Ebert in which they derived the universal asymptotic behavior of a large class of fronts – so-called pulled fronts—propagating into an unstable state. The review van Saarloos wrote on this type of fronts propagation, which occurs in many disciplines in the natural sciences, is his most highly cited paper. Together with Hohenberg he worked in particular on the classification of coherent structures (fronts, pulses sources and sinks) in the one-dimensional complex Ginzburg-Landau equation and its generalizations, which is the proper amplitude equation for traveling wave pattern forming systems. With Varma and Nussinov, van Saarloos reviewed the variety of ways in which Landau Fermi liquids can break down, giving rise to singular behavior. Together with Morozov, van Saarloos predicted that viscoelastic Poiseuile flow in a straight channel would exhibit a nonlinear instability at low Reynolds numbers and high Weissenberg numbers. The predicted instability was later experimentally observed. Together with van Hecke and several coworkers van Saarloos contributed to the understanding of force distributions in static granular packings and of the jamming transition in granular media. Van Saarloos was co-editor of the book
Dynamical Heterogeneities in Glasses, Colloids, and Granular Media in which he surveyed the theoretical and experimental research that deals with glassy physics and wrote the textbook
Soft Matter: concepts, phenomena and applications together with Vitelli and Zeravcic, which is supported by the website softmatterbook.online.
The Dutch Polder Model in science and research In a significant essay together with his predecessor as academy president, van Saarloos highlighted how research and education together have led to the success of this small country becoming a key player in the world of science and research. They also discussed how little is being invested in its research base and how this, together with increased international competition and increasing student numbers, erodes these trusted foundations. The authors then made suggestions about the ways in which the country can recover and relish in their big successes while making sure that research plays a big part in their nation's future. ==Awards and honors==