Quark Matter in the Core of Neutron Stars and Its Consequences on Non-radial Oscillations

We study the possibility of existence of deconfined quark matter (QM) in the core of neutron stars (NS)s and its relation to non-radial oscillation (NRO) modes in NS/ hybrid stars (HS)s. We use relativistic mean field models to describe the nuclear matter at low densities and the Nambu–Jona-Lasinio (NJL) model to describe QM at high densities. A Gibbs construct is used to study the hadron-quark phase transition (HQPT) at densities about few time nuclear saturation density ( \(\rho _0\) ). Within the model, the mixed phase appears at density about \(2.5 \rho _0\) and ends at density about \(5 \rho _0\) beyond which the pure quark phase appears. The existence of QM in the core enhances the NRO frequencies in HSs compared to NSs of the same mass and this enhancement is significantly large for the g modes.