Graviton

Quantum particle of gravity fields. Gravitons are bosons and belong in the lepton family.

Gravitational waves may be viewed as coherent states of many gravitons, much like the electromagnetic waves are coherent states of photons.

The force of gravitons is exceptionally weak compared to other elementary particles, which means significant amounts are required to produce observable macroscopic effects. This is why graviton production is generally an inefficient and energy-draining effort, and is rarely employed. Exceptions to this rule include such exotic devices as Gravity-Well Generators.

The existence of gravitons is still under heavy debate and no known devices exist that utilize gravitons for sure.