  The neutron star's crust and mantel are typical examples of non-uniform bulk
systems with spacial localisations. When modelling such systems at low
temperatures, as is the case in the crust, one has to work with antisymmetrised
many-body states to get the correct fermion behaviour. Fermionic molecular
dynamics, which works with an antisymmetrised product of localised wave
packets, should be an appropriate choice. Implementing periodic boundary
conditions into the fermionic molecular dynamics formalism would allow the
study of the neutron star's crust as a bulk quantum system. Unfortunately, the
antisymmetrisation is a non-local entanglement which reaches far out of the
periodically repeated unit cell. In this proceeding, we give a brief overview
how periodic boundary conditions and fermionic molecular dynamics can be
combined without truncating the long-range many-body correlation induced by the
antisymmetry of the many-body state.
