In order to generate a desired quantum state, we should be able to lead the quantum system from an arbitrary initial state to the target state. If the state of a quantum system converges from any input states to the unique final state by repeatedly applying a single CPT map to it, such a quantum channel is called mixing. We present several useful theorems on the mixing and the ergodicity of quantum channels, and with the help of those theorems, we construct three schemes for generating entanglement.