Rod-shaped nanoparticles suspended in water can store the zeroes and ones of digital computing on the basis of the rods' physical location.
Most digital memories are made of solid matter. But Madhavi Krishnan at the University of Zurich in Switzerland and her colleagues stored bits of information using the position and orientation of small silver rods suspended in solution between plates that were 150 nanometres apart. The rods levitate at the mouth of one of two holes in the plates that form a T shape. A short electrical pulse or a beam of light can move a nanoparticle from one hole to the other.
By adjusting the geometry of the T, the team could control the lifetime of the stored bit, which they calculate could be as much as 30 years for their arrangement.
Nature Nanotech. http://doi.org/6x2 (2015)