  It is demonstrated the Fermi surface of dense neutron matter may experience a
rearrangement near the onset of pion condensation, due to strong momentum
dependence of the effective interaction induced by spin-isospin fluctuations.
In particular, the Fermi surface may take the form of a partially hollow sphere
having a spherical hole in its center (a ``Lifschitz bubble''). Thus, a second
(inner) Fermi surface may form as high-momentum single-particle states are
filled and low-momentum states are vacated. The influence of this phenomenon on
the superfluid transition temperature of the Fermi system is characterized with
the help of a separation transformation of the BCS gap equation. This work may
be viewed as a revival of the search for physical realizations of abnormal
occupation in infinite, homogeneous Fermi systems -- plausible instances in
which the quasiparticle distribution differs from that of an ideal Fermi gas
and Fermi liquid theory breaks down.
