Scalar Pair Creation in a Spinning Cosmic String Spacetime with Coulomb-Type Interactions and a Klein–Gordon Oscillator

We investigate the creation of neutral scalar particle–antiparticle pairs from the vacuum in a curved spacetime, specifically that of a spinning cosmic string, under the influence of external fields. The scalar field is governed by the Klein–Gordon equation modified by three distinct interactions: a minimally coupled vector potential A _μ , a non-minimally coupled vector potential X _μ , and a scalar potential V _s , each modeled by Coulomb-like profiles. In addition, we incorporate the Klein–Gordon oscillator, which introduces a confining mechanism for the field. Analytical solutions are obtained for the field modes, allowing us to derive exact expressions for the Bogoliubov coefficients, from which the pair production probability and particle number density are computed. We analyze the combined effects of spacetime topology (encoded by the cosmic string parameter α), rotational dynamics (via the spinning parameter J ₀ ), and quantum numbers (l,m), as well as the roles of each interaction. Our results demonstrate that both the non-minimal vector potential X _μ and the KG oscillator significantly enhance vacuum instability, even in the absence of the minimal coupling. These findings provide new insights into quantum field behavior in rotating, topologically nontrivial spacetimes and may offer implications for early-universe phenomena and analogue gravity models.