Relativistic quantum dynamics of spin-0 massive charged particle in the presence of external fields in 4D curved space-time with a cosmic string

In this work, we investigate the relativistic quantum dynamics of spin-0 massive charged particles in a 4D curved space-time, the generalization of a cosmic string space-time. We investigate the Klein–Gordon equation in the presence of external fields in the considered framework. We also investigate a quantum particle described by the Klein–Gordon oscillator in the curved background space-time in the presence of external fields. We see that the energy eigenvalues get modified in comparison with the results obtained in a cosmic string space-time.