For the first time, University of Illinois physicists have experimentally demonstrated how three-dimensional conduction is affected by the defects that plague materials. An understanding of these effects is important for many electronics applications, including ultrasonic waves in medical imaging, lasers for imaging and sensing, and electron waves for electronics and superconductors.

Scientists have long theorized, but never observed, that strong disorder causing interference on all sides can trap a matter wave in one place — a phenomenon known as Anderson localization.

The group used ultra-cold atoms moving as matter waves in a disordered laser beam to simulate electrons moving in waves through a metal. They used laser light as an analogy for a material, allowing them to completely characterize and control the disorder — a feat impossible in solids, which has made understanding and testing theories of Anderson localization difficult.

Eventually, researchers plan to use the measurements of Anderson localization and the mobility edge along with future work to explore other parameters to engineer materials that perform better in specific applications — in particular, high-temperature superconductors.

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Also: Ultrasonic guided waves are a nondestructive technique for monitoring damage in aircraft and rotorcraft structures.