Spinning test particle motion around a rotating wormhole
Abstract
In this work, we investigated the motion of spinning test particles around a rotating wormhole, extending, in this way, the previous work of Benavides-Gallego et al. [Phys. Rev. D 101, 124024 (2020)] to the general case. Using the Mathisson-Papapetrou-Dixon equations, we study the effective potential, circular orbits, and the innermost stable circular orbit (ISCO) of spinning test particles. We found that both the particle and wormhole spins affect the location of the ISCO significantly. On the other hand, similar to the nonrotating case, we also found two possible configurations in the effective potential: plus and minus. Furthermore, the minimum value of the effective potential is not at the throat due to its spin $a$, in contrast to the motion of the nonspinning test particles in a nonrotating wormhole, where the effective potential is symmetric, and its minimum value is at the throat of the wormhole. In the case of the ISCO, we found that it increases as the spin of the wormhole $a$ increases, in contrast to black holes where the presence of spin decreases the value of the ISCO. Finally, since the dynamical four-momentum and kinematical four-velocity of the spinning particle are not always parallel, we consider the superluminal bound, finding that the allowed values of the dimensionless particle's spin $s$ change as the wormhole's spin $a$ increases.