Hybrid quantum-classical algorithms and quantum error mitigation

TL;DR

This paper reviews hybrid quantum-classical algorithms and quantum error mitigation techniques, emphasizing their importance for NISQ devices and their potential to enable useful quantum applications in the near term.

Contribution

It provides a comprehensive overview of current hybrid algorithms and error mitigation methods, serving as a foundational reference for future research in NISQ quantum computing.

Findings

Hybrid algorithms are promising for NISQ devices.

Quantum error mitigation improves reliability of quantum computations.

The field is rapidly evolving with ongoing developments.

Abstract

Quantum computers can exploit a Hilbert space whose dimension increases exponentially with the number of qubits. In experiment, quantum supremacy has recently been achieved by the Google team by using a noisy intermediate-scale quantum (NISQ) device with over 50 qubits. However, the question of what can be implemented on NISQ devices is still not fully explored, and discovering useful tasks for such devices is a topic of considerable interest. Hybrid quantum-classical algorithms are regarded as well-suited for execution on NISQ devices by combining quantum computers with classical computers, and are expected to be the first useful applications for quantum computing. Meanwhile, mitigation of errors on quantum processors is also crucial to obtain reliable results. In this article, we review the basic results for hybrid quantum-classical algorithms and quantum error mitigation techniques. Since quantum computing with NISQ devices is an actively developing field, we expect this review to be a useful basis for future studies.