Fermi sea of heavy electrons (a Kondo lattice) is never a Fermi liquid.
I demonstrate a contradiction which arises if we assume that the Fermi surface in a heavy-electron metal represents a finite jump in occupancy. Therefore it does not and the resulting density of states has a sharp, deep anomaly at the Fermi energy which will appear in vacuum tunneling and many other experiments.
Anderson
Philip W
PW
Physics Department, Princeton University, Princeton, New Jersey 08544, USA.