Matter at super nuclear densities including pion condensates

Abstract
The authors investigate the nature of cold matter, both neutron matter and beta-stable nucleon matter, as a function of density in a model which allows for the appearance of a pion condensate viewed as a spontaneous breaking of chiral symmetry. They also consider the effect of allowing for the creation of the Delta (1236) resonances. The possible existence of an isomeric state of nucleon matter is found at 2-3 times nuclear matter density and the implications for neutron-star structure and heavy-ion collisions are discussed.