MIT physicists directly observed ultracold atoms in an "edge state," flowing along a boundary without resistance. The research could help physicists manipulate electrons to flow without friction in materials that could enable super-efficient transmission of energy and data.
Typically, electrons are free agents that can move through most metals in any direction. When they encounter an obstacle, the charged particles experience friction and scatter randomly like colliding billiard balls. But in certain exotic materials, electrons can appear to flow with single-minded purpose. In these materials, electrons may become locked to the material's edge and flow in one direction, like ants marching single-file along a blanket's boundary. In this rare "edge state," electrons can flow without friction, gliding effortlessly around obstacles as they stick to their perimeter-focused flow. Unlike in a superconductor, where all electrons in a material flow without resistance, the current carried by edge modes occurs only at a material's boundary. Now MIT physicists have directly observed edge states in a cloud of ultracold atoms. For the first time, the team has captured images of atoms flowing along a boundary without resistance, even as obstacles are placed in their path. The results, which appear today in Nature Physics, could help physicists manipulate electrons to flow without friction in materials that could enable super-efficient, lossless transmission of energy and data. "You could imagine making little pieces of a suitable material and putting it inside future devices, so electrons could shuttle along the edges and between different parts of your circuit without any loss," says study co-author Richard Fletcher, assistant professor of physics at MIT. "I would stress though that, for us, the beauty is seeing with your own eyes physics which is absolutely incredible but usually hidden away in materials and unable to be viewed directly." The study's co-authors at MIT include graduate students Ruixiao Yao and Sungjae Chi, former graduate students Biswaroop Mukherjee PhD '20 and Airlia Shaffer PhD '23, along with Martin Zwierlein, the Thomas A. Frank Professor of Physics. The co-authors are all members of MIT's Research Laboratory of…