Marija Vucelja is a statistical physicist interested in biophysics, soft condensed matter and computational physics. She studied mixing and clustering of particles in flows; problems that are relevant for understanding the formation of rain droplets and planetesimals, clumping of pollutants on water surfaces and have many industrial applications. She derived the compressibility of surface flows and described the aggregation-disorder transition of particles in flows. Using “chaotic mixing,” she substantially accelerated specific Monte Carlo algorithms (the main numerical tools for studying complex systems). Next, Marija investigated the emergence of clones in populations. Drawing analogies between glassy systems and population dynamics she calculated the rate of coalescence (the probability of two individuals belonging to the same clone). Lately, Marija’s focuses on anomalous thermal relaxations in various physical systems, non-reversible Markov Chains and biophysics (here especially population dynamics and evolution).