Asymptotic quasinormal modes of a coupled scalar field in the   Garfinkle-Horowitz-Strominger dilaton spacetime
  The analytic forms of the asymptotic quasinormal frequencies of a coupled scalar field in the Garfinkle-Horowitz-Strominger dilaton spacetime is investigated by using the monodromy technique proposed by Motl and Neitzke. It is found that the asymptotic quasinormal frequencies depend not only on the structure parameters of the background spacetime, but also on the coupling between the scalar fields and gravitational field. Moreover, our results show that only in the minimal couple case, i.e., $\xi$ tends zero, the real parts of the asymptotic quasinormal frequencies agrees with the Hod's conjecture, $T_H\ln{3}$. 
Songbai Chen and Jiliang Jing