Spontaneous scalarization within Scalar-Tensor theory using new conformal function in quark stars

Abstract

General relativity had been succeeding to describe gravitational phenomenon in weak-field gravity but some deviation had been observed in compact objects such as neutron stars and quark stars. This phenomenon of spontaneous scalarization which shown for the first time by Damour and Espasito-Farese appears in one of the modified gravity theories i.e., scalar tensor theory of gravity. We will study such novel phenomenon in quark stars. Furthermore, different to that of previous study, here we introduce new conformal function. A(φ) = 1 − Ln[1 − 0.5β(φ − φ0)2] We found that spontaneous scalarization using such conformal function appears for the first time when β ≈ −4.5. Furthermore, the scalarization effect depends on the equation of state (EoS) of the quark stars. The corresponding effect appears rather different when scalar Coulomb EoS or vector Coulomb EoS are used.