Investigations in the problem of pion condensation using generator co-ordinate methods

Pion condensation in neutron matter has been investigated using the generator coordinate method and a simple p-wave interaction. The assumption of a condensed mode corresponding to one pion momentum (determined variationally) helps evaluate all the necessary matrix elements exactly. The technique of charge projection from a coherent state of negative pions is discussed, and calculations have been carried out for the cases of average charge conservation, charge projection before variation and for a charge conserving trial function. The ground-state energies and the lowest excitations of the system are obtained from numerical solutions of the Hill-Wheeler equation.