Quantum flux is the state which describes the state of matter.
All matter in the universe resonates on a quantum level. This resonation has a unique signature which cannot be changed by any known process. It is the foundation of existence.
- Although nothing can change this signature, the Q might be able to do this. As they also can change the gravitational constant in the universe. Something no one else can.
Matter can be brought into a state of quantum flux. In lifeforms this can be detected by examine cellular RNA which will be asynchronous with normal matter. (TNG: "Parallels")
Subspace Transporters also brought matter in a state of quantum flux. This had the advantage that transporter range could be several light years. The Federation experimented with this concept but abandoned it when it proofed unreliable and required to much energy. Bok used such a device to board the Enterprise-D in 2370 (TNG: "Bloodlines")