Long-lived quantum speedup based on plasmonic hot spot systems

TL;DR

This paper proposes a plasmonic system with molecules in nanoparticle hot spots to achieve long-lived quantum speedup lasting over 500 femtoseconds, significantly surpassing previous systems like photosynthetic complexes.

Contribution

The authors design a plasmonic hot spot system that extends the duration of quantum speedup beyond 500 fs, demonstrating a novel approach for quantum information processing.

Findings

Quantum speedup duration exceeds 500 femtoseconds.

Strong coherent coupling enhances quantum speedup longevity.

Plasmonic hot spot systems outperform biological systems in maintaining quantum coherence.

Abstract

Long-lived quantum speedup serves as a fundamental component for quantum algorithms. The quantum walk is identified as an ideal scheme to realize the long-lived quantum speedup. However, one finds that the duration of quantum speedup is very short in real systems implementing quantum walk. The speedup can last only dozens of femtoseconds in the photosynthetic light-harvesting system, which was regarded as the best candidate for quantum information processing. Here, we construct one plasmonic system with two-level molecules embodied in the hot spots of one-dimensional nanoparticle chains to realize the long-lived quantum speedup. The coherent and incoherent coupling parameters in the system are obtained by means of Green's tensor technique. Our results reveal that the duration of quantum speedup in our scheme can exceed 500 fs under strong coherent coupling conditions, which is several times larger than that in the photosynthetic light-harvesting system. Our proposal presents a competitive scheme to realize the long-lived quantum speedup, which is very beneficial for quantum algorithms.