[ealloc]

Probably it is referring to the overlap in mathematics between condensed matter and particle physics. Both fields can be seen as explorations of the mathematical framework known as Quantum Field Theory (with somewhat different interpretation) - many discoveries of QFT in one field also turn out to apply in the other, such as the renormalization group. For example, the Higgs mechanism was first discovered by a condensed matter physicist (Phil Anderson).

[guitarbill]

I think the experiments in the different field highlight this. Particle physics experiments keep getting bigger and more expensive (LHC, Kamiokande, etc). For condensed matter, you can give an undergrad liquid helium for experiments with superconductors, which will show QFT phenomena like quasi-particles. Even looking at symmetry breaking in condensed matter doesn't require (comparatively) huge experimental setups.

I don't think it's a stretch to say that if more people are actively experimenting and thinking about problems in a field, the more likely new results are going to be found. (That's not to say particle physics experiments aren't useful.)