Crystallization of dense neutron matter

The equation of state for cold neutron matter at high density is studied in the $t$-matrix formulation and it is shown that energetically it is convenient to have neutrons in a crystalline configuration rather than in a liquid state for values of the density exceeding 1.6 × ${10}^{15}$ g/${\mathrm{cm}}^3$. The study of the mechanical properties indicates that the system is stable against shearing stresses. A solid core in the deep interior of heavy neutron stars appears to offer the most plausible explanation of speed-ups observed in the Vela pulsar.