IMPLEMENTATION OF CONTROLLED-HADAMARD GATE AND GENERATION OF W-TYPE STATE BASED ON ATOMIC ENSEMBLES

A Controlled-Hadamard gate based on the Rydberg blockade mechanism is constructed, and the n-qubit W-type state by using the Controlled-Hadamard gate and C-NOT gate is prepared. The Rydberg state is chosen as the excited state (an assistant state), and the two ground states are chosen to store information. The effect of the decay of the excited state can be neglected, because the implement time of the gate operation is much shorter than the lifetime of the ground state. A large number of atomic ensembles W-type states can be obtained by this scheme. This method also provides a way for the realization of scalable quantum computation.