  A highly feasible dressed-state scheme, which greatly speeds up the adiabatic
population transfer of a quantum system, is applied for implementing a fast
CNOT gate in a cavity QED system. The cavity QED system consists of two
identical five-level atoms which are respectively trapped in two optical
cavities connected by a fiber. With the help of quantum Zeno dynamics, the CNOT
gate is constructed by three steps with six pulses. Because the adiabatic
condition is not necessary to be considered and all of the pulses are smoothly
turned on and off, the scheme is fast and feasible in experiment. Numerical
simulations indicate that the average fidelity for constructing the CNOT gate
is quite high and the gate operation time is relatively short. Moreover, the
effects on the fidelity of the atomic spontaneous emission and the photon
leakages from the cavities are discussed by the master equation and the result
shows the scheme is robust against the decoherence.
