Wandering Bose-Einstein condensate may lead to scalable quantum computer

Enlarge / A computer model of a Bose-Einstein condensate, showing some of its wave-like nature. (credit: NASA)

Although I often write about quantum computing, I mainly write about two forms: gate quantum computing and adiabatic quantum computing. There is a third, though, called quantum walks. Quantum walks are found in nature: a quantum walk is how the electron-transfer step in photosynthesis works. Now researchers have gotten entire clouds of atoms to go marching to their quantum beat.

Quantum walks can be implemented with light, but you would need to make a new computer for every calculation. In a Bose-Einstein condensate, however, the roles of light and matter are reversed. Researchers have used this to demonstrate a BEC quantum walk.

A bevy of quantum computers

Before we get into it, let’s quickly compare the different quantum-computer types. A gate quantum computer is the most familiar. A calculation is performed using discrete logic operations using a collection of gates, and the answer is read out at the end.