Phase Transition and Anisotropic Deformations of Neutron Star Matter
  The Skyrme model is a low energy, effective field theory for QCD which when coupled to a gravitational field provides an ideal semi-classical model to describe neutron stars. We use the Skyrme crystal solution composed of a lattice of $\alpha$-like particles as a building block to construct minimum energy neutron star configurations, allowing the crystal to be strained anisotropically. We find that below 1.49 solar masses the stars' crystal deforms isotropically and that above this critical mass, it undergoes anisotropic strain. We then find that the maximum mass allowed for a neutron star is 1.90 solar masses, in close agreement with a recent observation of the most massive neutron star yet found. The radii of the computed solutions also match the experimentally estimated values of approximately 10km. 
S. G. Nelmes and B. M. A. G. Piette
astro-ph.SR hep-ph nucl-th