Implementation of efficient quantum search algorithms on NISQ computers

Despite the advent of Grover's algorithm for the unstructured search, its successful implementation on near-term quantum devices is still limited. We apply three strategies to reduce the errors associated with implementing quantum search algorithms. Our improved search algorithms have been implemented on the IBM quantum processors. Using them, we demonstrate three- and four-qubit search algorithm with higher average success probabilities compared to previous works. We present the successful execution of the five-qubit search on the IBM quantum processor for the first time. The results have been benchmarked using degraded ratio, which is the ratio between the experimental and the theoretical success probabilities. The fast decay of the degraded ratio supports our divide-and-conquer strategy. Our proposed strategies are also useful for implementation of quantum search algorithms in the post-NISQ era.

Automated summary

This study successfully implemented optimized quantum search algorithms using three strategies, achieving higher success probabilities than previous works and demonstrating the first successful five-qubit search on the IBM quantum processor. The fast decay of the degraded ratio supported the divide-and-conquer strategy, indicating that the proposed strategies are beneficial for implementing quantum search algorithms in the post-NISQ era.