Hypermatter

Hypermatter is an exotic material used for high-capacity power generators in Star Wars.

Hypermatter was tachyonic matter that existed in hyperspace. When constrained by realspace, charged tachyons were annihilated as they accelerated to infinite speed within a reactor. The hyperdrive adjusted the faster-than-light hypermatter particles to allow a ship to jump to light-speed without changing its complex mass and energy.