Implementation of a multiqubit quantum phase gate in a neutral atomic ensemble via the asymmetric Rydberg blockade

Abstract

We report a scheme for implementing a multiqubit quantum phase gate in a neutral atomic ensemble via an asymmetric Rydberg blockade. The multiqubit gate is successfully realized by following a three-step approach. The neutral-atom qubits are always illuminated by the common laser beams and therefore individual addressing of the atoms is not required. The gate errors induced by atomic spontaneous emission, imperfect excitation blockade, and atomic motion are discussed.