Heralded and high-fidelity solid-state quantum Toffoli and Fredkin gates via practical microcavity-mediated photon scattering

Semiconductor quantum dot (QD) is an attractive candidate for realizing solid-state quantum gates, and photon is an excellent assistant for implementing quantum gates on the distributed QDs. Here, we propose two schemes for high-fidelity solid-state quantum gates on the electron spins of QDs embedded in the double-sided optical microcavities, including the three-qubit Toffoli gate and Fredkin gate. Although, the two quantum gates are implemented with the practical photon scattering mediated by the QD-cavity system, the computing errors originating from the imperfect involved in the photon-scattering process are eliminated by the failure-heralded pattern, which converts the error events into the detectable photon losses. Accordingly, the fidelities of the two quantum gates are guaranteed robust to the realistic parameters of the practical photon-scattering process. In addition, experimental requirements for realizing the high-fidelity quantum gates are relaxed. These interesting features provide the possibility of realizing high-fidelity quantum gates on solid-state QD systems using the feasible and practical photon scattering, which can lead to the construction of high-fidelity scalable quantum network further.