中国科学技术大学彭新华团队近日研究了原子气体相互作用的放大机制。相关论文于2025年5月8日发表在《美国科学院院刊》杂志上。
在量子放大器中使用原子、分子和自由电子极大地提高了精度测量，为微波激射器和激光器等极低噪声量子器件的发展铺平了道路。课题组研究了相互作用自旋的信号放大，并使用相互作用的碱金属和稀有气体的混合物观察了磁场的放大。与用作放大器的非相互作用系统相比，研究组证明了随机原子碰撞引起的相互作用会产生两种不同的放大现象。 这些现象为增强量子传感能力提供了必要的资源。
该结果表明，磁场可以被放大至少两个数量级，从而增强对每根赫兹飞秒级的磁灵敏度。此外，研究组报告了一种对应现象，即去放大，在某些频率范围内，磁噪声响应被抑制了至少一个数量级。在这项工作中，碱金属和惰性气体自旋弱耦合。研究组进一步探索了当两种自旋气体逐渐进入强耦合状态时，放大性能如何随相互作用强度而变化，揭示了迄今为止尚未探索的放大效应，这些效应有望提高精度测量。
附：英文原文
Title: Amplification mechanism with interacting atomic gases
Author: Jiang, Min, Qin, Yushu, Wang, Yuanhong, Huang, Ying, Peng, Xinhua, Budker, Dmitry
Issue&Volume: 2025-5-8
Abstract: The use of atoms, molecules, and free electrons in quantum amplifiers has greatly advanced precision measurements, paving the way for the development of extremely-low-noise quantum devices such as masers and lasers. Here, we investigate the signal amplification of interacting spins and observe the amplification of magnetic fields using mixtures of interacting alkali-metal and noble gases. In contrast to noninteracting systems used as amplifiers, we demonstrate that interactions resulting from random atomic collisions give rise to two distinct amplification phenomena. These phenomena provide essential resources for enhancing quantum sensing capabilities. Our results show that magnetic fields can be amplified by at least two orders of magnitude, enhancing magnetic sensitivity to the femtotesla per root hertz level. Additionally, we report a counterpart phenomenon, deamplification, where the magnetic noise response is suppressed by at least one order of magnitude within certain frequency regimes. In this work alkali-metal and noble-gas spins are weakly coupled. We further explore how the performance of amplification changes with the interaction strength as the two spin gases gradually enter the strong-coupling regime, unveiling hitherto unexplored amplification effects that hold promise for enhancing precision measurements.
DOI: 10.1073/pnas.2419683122
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2419683122