The aim of this work is about establishing and analyzing the Hamiltonian for entangled photon generation in a micro PANDA ring resonator for a quantum key generation unit in quantum cryptography processing. The reduced density matrix for two level states of qubits is also analyzed by using dynamics Heisenberg equation of motion. The master equation in the thermal effect shows fluctuation of the corresponding c-operators in phase space. The optimum simulation result for probability of qubit states survive for the existence of a surrounding heat bath is also showed and discussed.