Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China
; SE Univ, Dept Phys, Nanjing 210096, Peoples R China
In this paper, we discuss radiation fields in a compact space of finite size instead of that in a cavity for investigating the coupled atom-radiation field system. Representations of T(I) x SO(4) group are used to give a formulation for kinematics of the radiation fields. The explicit geometrical parameter dependence of statistical properties of radiation fields is obtained. Our results show remarkable differences from those of the black-body radiation system in free space.