Superfluid liquid crystals: pasta phases in neutron star crusts

Understand

The pasta phases predicted to occur near the inner boundary of the crust of a neutron star resemble liquid crystals, a smectic A in the case of sheet-like nuclei (lasagna) and the columnar phase in the case of rod-like nuclei (spaghetti).

• An important difference compared with usual liquid crystals is that the nucleons are superfluid.
• We develop the hydrodynamic equations for this system and use them to study collective oscillations.
• Nucleon superfluidity leads to important qualitative differences in the spectra of these oscillations and also increases their frequencies compared with ordinary liquid crystals.