Quasinormal modes of massless scalar field perturbation of a Reissner-Nordstrom de Sitter black hole with a global monopole

The quasinormal modes of massless scalar field perturbation of the Reissner-Nordstrom de Sitter black hole with a global monopole is investigated using the 6th order WKB method. The results show that the magnitude of the real part of the quasinormal frequencies decreases, while the magnitude of the imaginary one increases as b (related to eta-the scale factor of symmetry-broking) increases for fixed angular harmonic index l, overtone index n, cosmological constant Lambda and charge Q. For fixed l, n, Lambda, and b, the damping of massless scalar field in the space-time of the Reissner-Nordstrom de Sitter black hole with a global monopole faster and faster at first and afterwards becomes slower and slower with the increase of Q when the cosmological constant Lambda is smaller, while the cosmological constant Lambda is larger, the damping becomes faster and faster all the way with the increase of Q.