声音定位装置

The shortest distance between two points may be a straight line, but try telling that to electrons: when current flows down a wire, these particles zig and zag, moving indirectly from one end to the other. But now researchers have sped single electrons straight to their destinations using sound. The work is in the journal Nature. [Rob McNeil et al., "On-demand single-electron transfer between distant quantum dots"]

An electron’s quantum state carries information, making it important for a viable quantum computer. As the particle staggers down a wire, however, its state loses coherence—the electron “forgets” the information it carried.

To make it travel more efficiently, researchers blasted a short burst of sound at an electron trapped in an energy well. The sound wave “lifted” the electron, speeding it directly towards an empty well. Once it reached its destination, a sound burst from the opposite direction sent the electron back to its original location.

This discovery is a stop toward quantum computing, which requires the controlled transfer of single electrons. But it could also have another application: electron ping-pong. Researchers have bounced an electron back and forth up to 60 times. Nice nano-rally.

—Sophie Bushwick