There is an interesting article at http://www.rdmag.com/news/2016/01/heavy-fermions-get-nuclear-boost-way-superconductivity
The question it sparks in my mind is, if heavy fermions act as if they have a large mass electrons, could they behave similar to Muon's and cause fusion of the host material is deuterated? I recall one paper that discussed the effective mass of electrons in metal potentially altering the electron screening potential. Could large effective mass of heavy fermions improve the expected fusion rates for deuterated metals? It could be fun to work out.
