Q: I keep hearing about quantum computing. What is it? Does it really work? 

A: Quantum computing, if it can become a reality, depends on exploiting the strange behavior of atoms on a very short scale, says Mark Saffman, a professor of physics at UW-Madison. Shrinking transistors, the existing route to faster, cheaper and smaller computer chips, could eventually lead to a transistor that is one atom in size.

"When that happens, you can no longer predict how the transistor will work with classical methods," explains Saffman. "You have to use the physics that describes atoms: quantum mechanics."

At that point, he says, "you open up completely new possibilities for processing information. There are certain calculational problems... that can be solved exponentially faster on a quantum computer than on any foreseeable classical computer."

Describing how this could happen is not easy, since quantum mechanics allows two distant particles to "talk" to each other, or allows one particle to be in two places at once. Last year, however, Saffman and Thad Walker, another UW-Madison professor of physics, created a type of gate that would be essential to a quantum computer.

"Theoretically, quantum computing offers huge advantages in size, speed and computing ability," says Saffman, "but it's not going to be easy to get from here to there."

- Produced in cooperation with University Communications