Toner's broad interests in condensed matter physics span the gamut from topics in "statistical physics and the hydrodynamics of systems ranging from hard to soft condensed matter and from passive to active systems".
If one asks a large collection of people arranged in two dimensions, each of whom can only see a few nearest neighbors, to all point in the same direction, they could not do so (this is the Mermin-Wagner theorem).
[5] With Niladri Sarkar and Abhik Basu, Toner developed the hydrodynamic theory of flocking at a solid-liquid interface.
[9] In addition to formulating the Toner–Tu equations, Toner has made contributions to a wide range of areas of condensed matter physics, including the theory of melting,[10] quasicrystals,[11] fluctuating membranes,[12] and disordered superconductors.
[13] In 2006 Toner was elected a Fellow of the American Physical Society "for a wealth of contributions to the theory of correlations, fluctuations, topological defects, and anomalous elasticity and hydrodynamics of partially ordered phases.