Probing Exotic Core Phases of Neutron Stars through Spacetime Curvature in Modified Gravity

Abstract

Neutron stars (NSs), superdense objects with exceptionally strong gravitational fields, provide an ideal laboratory for exploring general relativity (GR) in the high-curvature regime. They also present an exciting opportunity to investigate new gravitational physics beyond the traditional framework of GR. Thus, investigating modified theories of gravity in the context of superdense stars is intriguing and essential for advancing our understanding of gravitational phenomena in extreme environments. Energy momentum squared gravity (EMSG) is a modified theory of gravity that extends GR by including nonlinear terms involving the energy-momentum tensor Tμν . In this study, we investigate the effect of EMSG on the curvature of NSs by using three relativistic mean-field (RMF) equations of state (EOSs) and three hadron-quark phase transition (HQPT) EOSs. This study mainly focuses on the Kretschmann scalar and Full contraction of the Weyl tensor curvature. We have calculated the radial variation and variation with the baryon density of the curvatures by varying the EMSG parameter α, and observed a distinct variation of the curvature invariants near the phase transition region, which may help us to probe the exotic core phases inside NSs.