Building a Faster Qubit

Computers are designed around basic components called "bits," which switch between "on" and "off" positions and are used to perform all of the myriad computations that the computer software runs on. One major realm of study is the attempt to create qubit, a computer bit that uses quantum physics to be both "on" and "off" simultaneously. The goal is to use these qubits to build a quantum computer, which could perform calculations exponentially faster than traditional computers.

The problem with previous attempts to create a qubit has been in stabilizing them. Quantum systems are notoriously delicate, because almost any interaction causes the quantum wave function to collapse into a single state. Maintaining the decoherence, the "on" and "off" nature simultaneously, has proven a real challenge.

A new paper in Nature Physics shows that work by researchers from the University of Michigan, U.S. Naval Research Laboratory, and University of California at San Diego, may have finally stabilized the duality within the qubit. Using lasers, the scientists are able to trap the spin of a single electron in a "dark state" which doesn't absorb the light. Because the light is not absorbed, the wave function doesn't collapse.

Not only is this qubit the first one to be stable, it's also the fastest. The lasers allow manipulation of the qubit at a rate of a billion times per second, which translates into a computing speed of about a GigaHertz.

Related Articles:

• What is a Quantum Computer?
• Quantum Physics Overview
• Science Daily - Fastest Quantum Computer Building Block Created
• Nature Physics - Coherent population trapping of an electron spin in a single negatively charged quantum dot (abstract)