Geodesic circular orbits sharing the same orbital frequencies in the black string spacetime

Abstract

Here we consider isofrequency pairing of geodesic orbits that share the same three orbital frequencies associated with $\Omega^{\hat{r}}$, $\Omega^{\hat{\varphi}}$, and $\Omega^{\hat{\omega}}$ in a particular region of parameter space around black string spacetime geometry. We study the effect arising from the extra compact spatial dimension on the isofrequency pairing of geodesic orbits and show that such orbits would occur and become in a cylindrical manner in the allowed region as particles move along the black string. We find that the effect due to the extra dimension leads to an increase in the number of the isofrequency pairing of geodesic orbits. We also find that isofrequency pairing of geodesic orbits in the region of parameter space can not be realized beyond the critical value $J_{cr} \approx 0.096$ of the conserved quantity of the motion due to the extra compact spatial dimension for given parameters of the black string.