Superradiance and black resonator strings encounter helical black strings

A bstract We construct a cohomogeneity-1 helical black string in six-dimensional Einstein gravity. The solution branches from the onset of gravitational superradiant instability equal-spinning Myers-Perry string. isometry group is ℝ T × U(1) Z SU(2), where first two are isometries generated by linear combinations time translation, shifts along string, and rotation, each which individually broken instability. stationary, non-axisymmetric, has nonzero horizon velocity despite absence momentum direction. entropy higher than that but lower cohomogeneity-2 “black resonator strings” (recently found) when solutions overlap microcanonical ensemble. approaches zero reaches its maximum given speed light. Nevertheless, we find no evidence for existence regular horizonless this limit.