Multiple Query Optimization using a Hybrid Approach of Classical and Quantum Computing

TL;DR

This paper introduces a hybrid classical-quantum algorithm for the NP-hard multiple query optimization problem, demonstrating high qubit efficiency and promising scalability for near-term quantum computers despite current hardware limitations.

Contribution

It presents a novel hybrid algorithm for MQO on gate-based quantum computers, achieving near 99% qubit efficiency and outperforming existing quantum annealer approaches.

Findings

Algorithm handles small problem sizes due to limited qubits.

Qubit efficiency is close to 99%, nearly double the state of the art.

Scalability analysis shows promising results for future larger quantum computers.

Abstract

Quantum computing promises to solve difficult optimization problems in chemistry, physics and mathematics more efficiently than classical computers, but requires fault-tolerant quantum computers with millions of qubits. To overcome errors introduced by today's quantum computers, hybrid algorithms combining classical and quantum computers are used. In this paper we tackle the multiple query optimization problem (MQO) which is an important NP-hard problem in the area of data-intensive problems. We propose a novel hybrid classical-quantum algorithm to solve the MQO on a gate-based quantum computer. We perform a detailed experimental evaluation of our algorithm and compare its performance against a competing approach that employs a quantum annealer -- another type of quantum computer. Our experimental results demonstrate that our algorithm currently can only handle small problem sizes due to the limited number of qubits available on a gate-based quantum computer compared to a quantum computer based on quantum annealing. However, our algorithm shows a qubit efficiency of close to 99% which is almost a factor of 2 higher compared to the state of the art implementation. Finally, we analyze how our algorithm scales with larger problem sizes and conclude that our approach shows promising results for near-term quantum computers.