Radiative properties of a static two-level atom in a cosmic dispiration spacetime

We investigate the influence of a cosmic dispiration on the radiative processes of a static two-level atom immersed in a bath of fluctuating massless quantum scalar field. The cosmic dispiration is regarded as a combination of the two types of line defect, namely, an idealized cosmic string and a screw dislocation associated respectively with the curvature and torsion. Through comparison with the case in a free Minkowski spacetime, our results indicate that the presence of the cosmic dispiration can enhance or weaken and even prohibit the atomic spontaneous emission process, depending upon the position of the atom with respect to the line defect. Moreover, the atomic decay rates respectively in three types of topological defect spacetime are compared in order to reveal the difference and relation between topological defects. Our work suggests that by virtue of the combination of a cosmic string and a screw dislocation, theoretically the radiative processes of atoms can be adjusted and controlled more flexibly.