陽子トンネリングを模倣する超伝導量子回路の開発(Building a superconducting quantum circuit that follows protons on the go)

2026-04-30 イェール大学

イェール大学の研究チームは、超伝導量子回路の性能に影響する微細な欠陥の原因として「プロトン(水素原子核)」の振る舞いに注目し、その動きを追跡する手法を開発した。量子ビットのコヒーレンス低下は材料中の不安定な原子レベルの揺らぎが要因とされるが、本研究はプロトンの位置変化がエネルギー損失を引き起こす仕組みを明らかにした。これにより、より安定した量子回路設計や材料選択が可能となり、量子コンピュータの信頼性向上に貢献する。将来的には大規模量子計算の実現に向けた重要な基盤技術となると期待される。

陽子トンネリングを模倣する超伝導量子回路の開発(Building a superconducting quantum circuit that follows protons on the go)
A rendering of the new device that simulates quantum proton transfer in chemistry and biology.Image courtesy of researchers

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化学活性化の量子シミュレーションのためのパラメトリック発振器における非対称性制御 Asymmetry Control in a Parametric Oscillator for the Quantum Simulation of Chemical Activation

Alejandro Cros Carrillo de Albornoz, Rodrigo G. Cortiñas, Max Schäfer,, Nicholas E. Frattini, Brandon Allen, Delmar G.A. Cabral, Pablo E. Videla, Pouya Khazaei, Eitan Geva et al.
PRX Quantum  Published: 16 April, 2026
DOI: https://doi.org/10.1103/71yp-fqns

Abstract

Dissipative tunneling remains a cornerstone effect in quantum mechanics. In chemistry, it plays a crucial role in governing the rates of chemical reactions, often modeled as the motion along the reaction coordinate from one potential well to another. The relative positions of energy levels in these wells strongly influence the reaction dynamics. Chemical research will benefit from a fully adjustable, asymmetric double-well equipped with precise measurement capabilities of the tunneling rates. In this paper, we show a quantum simulator system that consists of a continuously driven Kerr parametric oscillator with a third-order nonlinearity that can be operated in the quantum regime to create a fully tunable asymmetric double-well. Our experiment leverages a low-noise, all-microwave control system with a high-efficiency readout, based on a tunnel Josephson junction circuit, of the which-well information. We explore the reaction rates across the landscape of tunneling resonances in parameter space. We uncover two counter-intuitive effects: (i) a weak asymmetry can significantly decrease the activation rates, even though the well in which the system is initialized is made shallower, and (ii) the width of the tunneling resonances alternates between narrow and broad lines as a function of the well depth and asymmetry. We predict by numerical simulations that both effects will also manifest themselves in ordinary chemical double-well systems in the quantum regime. Our work is a first step for the development of analog molecule simulators of proton transfer reactions based on quantum parametric processes.

1601コンピュータ工学
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