Loren N. Pfeiffer

In a thin sandwich of gallium arsenide, electrons don't behave like individual balls but like a single quantum liquid. If the layer is made just 70 nanometers thick, this liquid separates into two nearly independent flows, like oil on water.

A thin silver thread nearly as long as a hair's width, and inside it, pristine quantum laws hold sway. Physicists built a conductor where electrons can only move forward or backward, like on a perfectly straight single-lane road with no shoulders. On such a road, any pothole or pebble would normally destroy the fragile quantum state.