Implementation of efficient quantum search algorithms on NISQ computers

TL;DR

This paper demonstrates improved quantum search algorithms on IBM quantum processors, achieving higher success probabilities for 3- and 4-qubit searches and successfully executing a 5-qubit search for the first time on NISQ devices.

Contribution

The authors introduce error reduction strategies that enable more effective implementation of quantum search algorithms on near-term quantum hardware, including the first 5-qubit search on IBM quantum processors.

Findings

Higher success probabilities for 3- and 4-qubit searches.

First successful 5-qubit search on IBM quantum processor.

Divide-and-conquer strategy enhances algorithm robustness.

Abstract

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.