The state of matter of neutron stars is largely unknown. However, "starquakes" of neutron stars with extremely strong magnetic fields shed light into their exotic interior structure. Recent numerical simulations of the magneto-elastic oscillations of neutron stars strongly suggest that their liquid interior, which mainly consists of extremely compressed neutrons and some protons and electrons, is in a superfluid state. When including superfluidity in the models the predicted frequencies of the oscillations agree better with observations and the magnetic field strength estimates agree with alternative estimates. Moreover, the oscillations should live longer than in models without superfluidity.

  Neutron star structure: A solid crust with a thickness of about 1km surrounds a liquid core of about 10km whose state of matter is largely unknown. 

For a little more insight into the project see this：http://www.mpa-garching.mpg.de/mpa/research/current_research/hl2014-1/hl2014-1-en.html