  To resist decoherence from destroying the phase factor of qubit state, it is
important to use decoherence-free states for processing, transmitting and
storing quantum information in quantum computing and quantum communication. We
propose a practical scheme using four atoms with decoherence-free states in a
single-mode cavity to realize the entanglement and fundamental quantum logic
gates. The transmission of quantum information can be made directly from one
atom to another, in which the cavity is only virtually excited. The possible
application and the experimental requirement of our proposal are discussed
