単一原子のスピンのリアルタイム反転を観測（Quantum researchers observe real-time switching of the magnet in the heart of a single atom）

2025-08-28 デルフト工科大学（TU Delft）

Artist impression, based on actual measurement data, of the nuclear spin of an atom flipping between distinct quantum states. The flipping was observed as a fluctuation in the electrical current passing through the atom on a timescale of seconds. Credits: Scixel

＜関連情報＞

• https://www.tudelft.nl/en/2025/tnw/quantum-researchers-observe-real-time-switching-of-the-magnet-in-the-heart-of-a-single-atom
• https://www.nature.com/articles/s41467-025-63232-5

表面上の原子の核スピンの単一ショット読み出し Single-shot readout of the nuclear spin of an on-surface atom

Evert W. Stolte,Jinwon Lee,Hester G. Vennema,Rik Broekhoven,Esther Teng,Allard J. Katan,Lukas M. Veldman,Philip Willke &Sander Otte
Nature CommunicationsPublished:21 August 2025
DOI:https://doi.org/10.1038/s41467-025-63232-5

Abstract

Nuclear spins owe their long-lived magnetic states to their excellent isolation from the environment. At the same time, a finite degree of interaction with their surroundings is necessary for reading and writing the spin state. Therefore, detailed knowledge of and control over the atomic environment of a nuclear spin is key to optimizing conditions for quantum information applications. While various platforms enabled single-shot readout of nuclear spins, their direct environments were either unknown or impossible to controllably modify on the atomic scale. Scanning tunneling microscopy (STM), combined with electron spin resonance (ESR), provides atomic-scale information of individual nuclear spins via the hyperfine interaction. Here, we demonstrate single-shot readout of an individual ⁴⁹Ti nuclear spin with an STM. Employing a pulsed measurement scheme, we find its lifetime to be in the order of seconds. Furthermore, we shed light on the pumping and relaxation mechanisms of the nuclear spin by investigating its response to both ESR driving and tunneling current, which is supported by model calculations. These findings give an atomic-scale insight into the nature of nuclear spin relaxation and are relevant for the development of atomically assembled qubit platforms.