Microwave Technology for Quantum Computers?

The National Institute of Standards and Technology has demonstrated the use of microwave technology for performing quantum entanglement, which could make it possible to produce inexpensive quantum computers that could perform functions that today are possible only with lasers, which cost far more. The project was funded the Office of Naval Research, DARPA, the National Security Agency, and Sandia National Laboratories. Quantum entanglement will be the primary method for transporting information and performing error correction in future quantum computers, according to NIST.

Although electromagnetic energy has demonstrated that it can affect individual trapped ions, NIST says it is the first organization to demonstrate quantum entanglement using microwave energy. By positioning microwave ion traps 30 microns apart, NIST demonstrated this entanglement and while a laser was still needed to cool the device, it needed to be only an inexpensive type used in laser pointers, a far cry from the large expensive lasers typically used for quantum entanglement.

A gold ion trap on aluminum nitride substrate entangles two ions using microwave energy input to wires from three electrodes. The energy was used to rotate and entangle the spins of magnesium ions. The ions were held in place by electromagnetic fields generated by gold electrodes onto the substrate. Microwave radiation was then applied at about 2 GHz, which produced controlled rotation and entanglement of their spins states about 76% of the time. NIST is now working to improve its success rate to above 99.3%.