A long-standing mystery about nuclear magnetic resonance has finally been solved, an advance that could lead to clearer MRI images for medical uses and could provide better control of atoms for quantum computers.
The mystery was in the delicate flipping of the magnetic spin axes of atoms inside a magnetic resonance imaging, or MRI, machine — or any device that employs nuclear magnetic resonance, or NMR, a way of using powerful magnetic fields to study matter.
Controlling this flip is like moving a full bowl of soup without spilling it, explains Philip Grandinetti, an expert in NMR at Ohio State University in Columbus. If you move infinitely slowly, the soup will remain calm in the bowl, a kind of motion called “adiabatic.” Move too quickly, the existing theory predicts, and the soup will spill — that is, you will lose control of the atoms’ magnetic axes.