One-step implementation of the genuine Fredkin gate in high-Q coupled three-cavity arrays

摘要

We present two efficient methods for implementing the Fredkin gate with atoms separately trapped in an array of three high-Q coupled cavities. The first proposal is based on the resonant dynamics, which leads to a fast resonant interaction in a certain subspace while leaving others unchanged, and the second one utilizes a dispersive interaction such that an effective long-distance dipole-dipole interaction between two distributed target qubits is achieved by a virtually excited process. Both schemes can achieve the standard form of the Fredkin gate in a single step without any subsequent single-qubit operation. The effects of decoherence on the performance of the gate are also analyzed in virtue of the master equation, and strictly numerical simulation reveals that the average fidelity of the quantum gate is high.