The answer? It must be the Pauli Exclusion Principle
It causes atoms to take up the space they do, since electrons cannot all congregate in the lowest-energy state but must occupy higher energy states at a distance from lower-energy electrons, therefore matter made of atoms occupies space rather than being condensed.
As we saw in the last post, distance is key in the Coulomb Barrier
In order to accomplish nuclear fusion, the particles involved must first overcome the electric repulsion to get close enough for the attractive nuclear strong force to take over to fuse the particles.
Therefore, the BEC allows the atoms to get close enough for the strong force to take over and fusion takes place.
You know, this wasn't very clearly written. The point was supposed to be about the Pauli Exclusion Principle and somehow this didn't get explained. Very well, let me try again. The Pauli Exclusion Principle is what makes matter the way that it is. Matter takes up space, as mentioned above. The Pauli Exclusion Principle is why: two atoms, which must obey this principle, cannot share the same quantum state, and therefore must be far apart. For this reason, they are called "fermions", because they obey this principle. Bosons do not. As Bose and Einstein predicted, bosons will condense under appropriate conditions. This means that the atoms of matter will get closer together. The BECNF theory posits that a condensate is forming that is allowing the atoms to get close enough together in order to allow fusion to take place. Under normal conditions, this will not happen. The BECNF theory explains under what conditions these condensates may be forming which are allowing the Coulomb barrier to be overcome which will allow fusion at low temperatures.
With respect to the Coulomb barrier, fusion can take place either by the above theory, if proven correct, or by very high temperatures, which is the way it is being attempted by the hot fusioneers. Either way may work in theory, but what separates the two is that Rossi may have found out how to do this in a commercially feasible way, which would be quite an achievement.