احمد محمدی اسلامی

Using Fermi Golden rule, an expression for spontaneous emission rate between two eigenstates of atom is derived which is in term of the correlation functions of the electric field. The resulting expression is related to the imaginary parts of the vector potential Green function by using the fluctuation-dissipation theorem and Kubo’ formula in statistical mechanics. Finally by calculating The Green function of the system of an atom near a metallic slab, the spontaneous emission rate is calculated. This method does not require the explicit form of the electric field operator, thus the calculations are simpler.