Temporal information processing induced by quantum noise

• Published in: Physical review research 2023-04, Vol.5 (2), p.023057, Article 023057
• Main Authors: Kubota, Tomoyuki, Suzuki, Yudai, Kobayashi, Shumpei, Tran, Quoc Hoan, Yamamoto, Naoki, Nakajima, Kohei
• Format: Article
• Language: English
• ISSN: 2643-1564; 2643-1564
• DOI: 10.1103/PhysRevResearch.5.023057

Quantum computing has been moving from a theoretical phase to practical one, presenting daunting challenges in implementing physical qubits, which are subjected to noises from the surrounding environment. These quantum noises are ubiquitous in quantum devices and generate adverse effects in the quantum computational model, leading to extensive research on their correction and mitigation techniques. But do these quantum noises always provide disadvantages? We show that some abstract quantum noise models can induce useful information processing capabilities for temporal input data in a framework called quantum reservoir computing. We demonstrate this ability in several typical benchmarks and investigate the information processing capacity to clarify the framework's processing mechanism and memory profile. We verified our perspective by implementing the framework in a number of IBM quantum processors and obtained similar characteristic memory profiles with model analyses. As a surprising result, information processing capacity increased with quantum devices’ higher noise levels and error rates. Our study opens up a path for diverting useful information from quantum computer noises into a more sophisticated information processor.