2025-01-23 米国国立標準技術研究所 (NIST)
米国標準技術研究所（NIST）の研究者は、巨視的な「リュードベリ原子」を使用して、極めて高精度な温度測定が可能な新しい温度計を開発しました。この温度計は量子物理学の原理を利用し、初期の工場校正なしで国際基準に直接対応可能な精度を実現します。リュードベリ原子は熱に敏感で、温度変化を電子のエネルギー跳躍で検出します。この技術は宇宙や高精度産業での温度測定に貢献し、原子時計の精度向上にも寄与します。
＜関連情報＞
- https://www.nist.gov/news-events/news/2025/01/new-atom-based-thermometer-measures-temperature-more-accurately
- https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.7.L012020
低温原子のリュードベリ状態における誘起状態移動を利用したミリ波黒体放射の一次量子温度測定 Primary quantum thermometry of mm-wave blackbody radiation via induced state transfer in Rydberg states of cold atoms
Noah Schlossberger, Andrew P. Rotunno, Stephen P. Eckel, Eric B. Norrgard, Dixith Manchaiah, Nikunjkumar Prajapati, Alexandra B. Artusio-Glimpse, Samuel Berweger, Matthew T. Simons, et al.
Physical Review Research Published: 23 January, 2025
DOI:https://doi.org/10.1103/PhysRevResearch.7.L012020
Abstract
Rydberg states of alkali-metal atoms are highly sensitive to electromagnetic radiation in the GHz-to-THz regime because their transitions have large electric dipole moments. Consequently, environmental blackbody radiation (BBR) can couple Rydberg states together at timescales. Here, we track the BBR-induced transfer of a prepared Rydberg state to its neighbors and use the evolution of these state populations to characterize the BBR field at the relevant wavelengths, primarily at 130 GHz. We use selective field ionization readout of Rydberg states with principal quantum number ∼30 in 85Rb and substantiate our ionization signal with a theoretical model. With this detection method, we measure the associated blackbody-radiation-induced time dynamics of these states, reproduce the results with a simple semiclassical population transfer model, and demonstrate that this measurement is temperature sensitive with a statistical sensitivity to the fractional temperature uncertainty of 0.09 Hz−1/2, corresponding to 26 K Hz−1/2 at room temperature. This represents a calibration-free SI-traceable temperature measurement, for which we calculate a systematic fractional temperature uncertainty of 0.006, corresponding to 2 K at room temperature when used as a primary temperature standard.
