Harvard University scientists have develop a miniaturized MRI device that could lead to large-scale quantum computers.

The did it by placing a powerful magnet at the scanning tip of an atomic force microscope to create a powerful magnetic field gradient in a volume of space just a few nanometers across. That allows them to stimulate and control the magnetic resonance of single electrons in a way that could easily be adapted for quantum computation.

Ref: arxiv.org/abs/1103.0546: Quantum Control Of Proximal Spins Using Nanoscale Magnetic Resonance Imaging