To visualize how this might work, put three marbles on a table and scoot them around. If you were able to keep track of and record the position of the marbles over time, their three paths might eventually trace a “braid.” Freedman imagines that his computer would be made of special “quasiparticles” found in exotic materials such as superconductors that “remember” where they have been. These particles might be braided or arranged using electric fields, and the shape of the braid would be used to represent data. Unlike other quantum bits, however, these quantum braids would be less vulnerable to external disturbances because their shapes would be robust.
Freedman’s work doesn’t stop with out-of-this-world thought experiments. He’s looking for a real material that can perform these topological tricks. “I’m a pure mathematician transitioning into materials designer,” he says. To help him, Freedman has recruited researchers with materials experience onto his team. Working together, they hope both to design and to fabricate a substance that has all the right properties for supporting error-free quantum computing.
This project, of course, marks quite a departure for Microscoft, a company associated with word processing software and desktop computing-not materials science or basic physics. For one thing, it will likely be decades before quantum computing becomes feasible, if it ever does. And for another, if Freedman is right, his advance will signal a quantum jump in computing that will make almost everything Microsoft does obsolete. “My fantasy,” says Freedman, “is that Bill Gates can get up someday and say Microsoft introduced the quantum computer and a software revolution at the same time.”