Quantum-Assisted Clustering Algorithms for NISQ-Era Devices

TL;DR

This paper introduces hybrid quantum-classical clustering algorithms suitable for NISQ-era devices, which require few qubits, improve performance, and are practical for near-term quantum computing applications.

Contribution

The paper develops new hybrid clustering algorithms that operate efficiently on small NISQ devices, requiring logarithmic qubits and offering performance or runtime benefits.

Findings

Algorithms require at most logarithmic qubits

Provide performance or runtime improvements over classical methods

Do not rely on black-box oracles

Abstract

In the NISQ-era of quantum computing, we should not expect to see quantum devices that provide an exponential improvement in runtime for practical problems, due to the lack of error correction and small number of qubits available. Nevertheless, these devices should be able to provide other performance improvements, particularly when combined with existing classical machines. In this article, we develop several hybrid quantum-classical clustering algorithms that can be employed as subroutines on small, NISQ-era devices. These new hybrid algorithms require a number of qubits that is at most logarithmic in the size of the data, provide performance improvement and/or runtime improvement over their classical counterparts, and do not require a black-box oracle. Consequently, we are able to provide a promising near-term application of NISQ-era devices.