Non-technical Abstract: Condensed matter physics has drawn inspiration from the motions of creatures ranging from bacteria to insects, fish, birds and migrating mammals to create the new field of active materials. Unlike atoms or molecules, which derive their energy from a heat source to move around in a random, undirected manner, many living creatures expend their energy to move along a preferred body axis, leading to unusual collective behaviors such as schooling, flocking and swarming. In this research, experiments will be launched to mimic some of these phenomena in laboratory systems made up of millimeter-sized grains energized by vibrations. Going beyond the biological motivation, the research team will create grains that move in designed ways to manipulate and assemble materials. Through this research, both graduate and undergraduate students will gain exposure to a variety of techniques and frontier areas in soft-condensed matter physics and be introduced to problems which have industrial relevance. The PI contributes to graduate education beyond his university by continuing to organize an annual summer school at UMass Amherst entitled Soft Solids and Complex Fluids. The PI also contributes to running an annual program for middle- and high-school teachers entitled Patterns Around Us.
Active matter is a new arena for non-equilibrium statistical mechanics, inspired by observed collective behavior in motile systems from bacteria to insects, fish, birds and migrating mammals. In this project, the research team will go beyond biomimetic motivations, and explicitly set aside the constraints and intents of biological design to create "active" granular particles that can give new material function and response to granular assemblies. The particular goal is to recognize and exploit the fact the symmetry of motion of individual units can be entirely different from the symmetry of interaction with other units. The team proposes to launch experiments to study the collective mechanics of vibrated grains which rectify noise to generate directed motion. They have parallel goals of (i) exploring new issues in the statistical physics of active matter, and (ii) developing methods of manipulating and assembling macroscopic matter. The major goal of this proposal is a comprehensive experimental study of the phase diagram of a number of classes of active particles, so that light may be shed on how activity can promote or disrupt specific kinds of ordering. Through this research, both graduate and undergraduate students will gain exposure to a variety of techniques and frontier areas in soft-condensed matter physics and be introduced to problems which have industrial relevance. The PI contributes to graduate education beyond his university by continuing to organize an annual summer school at UMass Amherst entitled Soft Solids and Complex Fluids. The PI also contributes to running an annual program for middle- and high-school teachers entitled Patterns Around Us.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
