Computronium

Computronium (not to be confused with Smart Materials) is any material that can be used as programmable matter. It refers to the best possible form of computing device for that amount of matter. These are usually artificial substances suitable for high efficiency computation; however, biological neural matter is also a form of computronium. Humans carry about 1.5 kilos of computronium in their heads as brain tissue. Materials suited for computronium include graphene, nanotubes and time crystals. It could also be comprised of intelligent, atom-sized nanobots and take the shape of anything imaginable including rocks, metal, and polymer, and be wirelessly controlled.

In The Singularity Is Near, Ray Kurzweil discusses a universe filled with computronium. He believes this could be possible until the late 22nd century by sending intelligent nanobots through the universe faster than light, e.g. by using wormholes.

A computronium node is any discrete megascale data processing structure constructed from computronium, such as a Matrioshka brain. Most Dyson Swarms and Matrioshka brains consist of millions or billions of computronium nodes, generally connected by communication wormholes.