Quantum torpedo
The quantum torpedo was a weapon developed by Starfleet to replace the standard photon torpedo. It was first developed in 2368, and deployed throughout the fleet in the beginning of 2371.
Quantum torpedoes were not completely effective against solid neutronium.
Background
The Star Trek: Deep Space Nine Technical Manual states that quantum torpedoes rely on harnessing zero-point energy, increasing their destructive power to above the maximum capable with a photon torpedo. Specifically, the zero-point initiator is activated by an uprated photon torpedo warhead at 19.5 isotons, producing a final explosive yield of 50+ isotons. Furthermore, the pattern of energy release (duration, vector, etc.) makes the blast more difficult to disperse by starship shields, increasing the tactical effectiveness beyond that of a photon torpedo even more.
According to the script for DS9: "Sacrifice of Angels", the Federation fighters used to attack the center of the Dominion lines were armed with quantum torpedoes.
Quantum torpedoes were first seen in DS9: "The Search, Part I".
On a strange note in DS9: "Valiant", it takes six quantum torpedos to destroy the Jem'Hadar attack ship in question, after it had taken at least two or three passes of pulse phaser fire. This leads one to speculate about just what was wrong with the Valiant's weapon systems. Similar sequences involving the Defiant have never taken more than one or two quantum torpedos to do the same job (barring the sequence in DS9: "The Siege of AR-558" which was stock footage from Valiant).
According to the videogame manual for Star Trek: Starfleet Command III, the quantum torpedo, "Utilizes an eleven-dimensional spacetime membrane suspended in an ultra-clean vaccum within the projectile. The membrane is then twisted into a string and isolated from the background vaccum, resulting in the creation of a new particle, which is accompanied by the release of a tremendous amount of energy." However, this is a videogame, and probably inaccurate.
