Quantum reality

Quantum reality, or quantum universe, was the term used to describe the alternate timelines in which all possible outcomes for any event take place. Each quantum reality was its own separate parallel universe characterized by a unique quantum signature which could not be altered. All matter resonated on a quantum level with this signature within the universes. Before 2370, the existence of different quantum realities was considered only a theory in quantum physics. Under normal circumstances quantum universes remain separated from one another by barriers.

History
In 2370, Lieutenant Worf piloted the type 6 shuttlecraft Curie through a quantum fissure, which acted as a "keyhole" that intersected multiple quantum realities. The warp nacelles of the shuttle caused a small break in the barriers between realities and threw Worf into a state of quantum flux. The flux was intensified when Worf was near the subspace field pulse of Commander La Forge's VISOR. This had the effect of pushing Worf into new realities.

Eventually Lieutenant Commander Data was able to determine that, by piloting the same shuttle with which he had traversed the fissure in the first place and initiating a broad-spectrum warp field, Worf could seal the fissure and return to his own universe. This had the effect of transporting Worf back in time to a point before he encountered the fissure. However, as Data explained, due to the uncertainty principle, it was just as possible Worf would have ended up several days forward in time.

Quantum realities
Several different quantum realities were witnessed by Worf in 2370.
 * See: Parallel universe