Multiple-Qubit CkUm Logic Gates of Rydberg Atoms via Optimized Geometric Quantum Operations

Multiple-qubit logic gates, as an essential part of quantum logic gates, have wide practical application in quantum computation. Here, a scheme to directly construct a multiple-qubit logic gate CkUm${\rm C}_{k}{\rm U}<^>{m}$, in which k control atoms apply an universal operation U on each of m target qubits in the Rydberg atom system is proposed. The scheme, based on Rydberg blockade and geometric quantum operations as well as optimized control theory, can greatly reduce the qubit number and the operation steps, improving the speed and robustness of the gating compared to the conventional multiple-qubit gates consisting of single- and two-qubit gates. Taking the C2U2 gate as an example, the performance of the proposal is numerically evaluated in terms of the fidelity of the quantum gate as well as the robustness against the static systematic errors and spontaneous emission. This work may provide a significative reference for constructing universal multiple-qubit logic gates in future Rydberg atom experiments.

Automated summary

This paper proposes a scheme to directly construct multiple-qubit logic gates, which can greatly reduce the number of qubits and operation steps, improving the speed and robustness of the gates. The scheme is based on Rydberg blockade, geometric quantum operations, and optimized control theory. The performance of the proposed scheme is numerically evaluated on the C2U2 gate.