💡 **创新量子传感技术革新暗物质搜寻：** 研究人员引入了一种基于碱金属-21Ne自旋系统的宽带量子传感新方法，该系统如同一个灵敏的天线，能够捕捉到暗物质发出的微弱信号。与传统依赖窄带共振的慢速扫描技术不同，这种新方法显著提高了探测效率和覆盖范围。

🔄 **双重工作模式实现高稳定与高灵敏：** 该自旋系统在不同频率下展现出独特的行为。在低频时，它具备自适应噪声抵消能力，即使在复杂环境中也能保持高度稳定和灵敏。而在高频时，不同原子的自旋能够产生共振，有效放大信号，使得探测暗物质引起的微小效应更为容易，从而在不损失灵敏度的情况下大幅拓宽了搜索带宽。

🚀 **拓展搜寻范围并设定新物理约束：** 该实验覆盖了从0.01 Hz到1000 Hz的极宽频率范围，实现了对轴子类暗物质的全面搜寻。研究结果在某些频率范围内，对轴子与中子相互作用的灵敏度超越了先前天文观测的极限；在实验室测量中，也为轴子与质子相互作用设定了迄今为止最严格的限制，为理解暗物质的本质提供了关键线索。

Dark matter makes up over 25% of the universe’s mass, holds galaxies together, and is essential to our understanding of cosmic structure. It doesn’t interact with light or other electromagnetic radiation, and is detectable only through its gravitational effects. While astrophysical and cosmological evidence confirms its presence, its true nature remains one of the greatest mysteries in modern physics.

A leading theory suggests that dark matter consists of extremely light, elusive particles called axions. Traditional axion searches rely on narrow-band resonance techniques, which require slow, step-by-step scanning across possible axion masses, making the process time-consuming.

In this study, researchers introduce a new broadband quantum sensing approach using an alkali-²¹Ne spin system, which works like a very sensitive antenna to listen for signals from dark matter. They identify two distinct ways the system behaves under different conditions. At low frequencies, the spin system naturally adjusts itself to cancel out noise or unwanted effects. This self-compensation makes the system stable and sensitive, even without fine-tuning. It’s like a car that automatically balances itself on a bumpy road, you don’t need to steer constantly. At higher frequencies, the system enters a state where the spins of different atoms resonate together. This resonance boosts the signal, making it easier to detect tiny effects caused by dark matter. Like two musical instruments playing in harmony, the combined sound is louder and clearer. This allows researchers to significantly expand the search bandwidth without sacrificing sensitivity.

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Their experiment covers a vast frequency range, from very slow oscillations (0.01 Hz) to very fast ones (1000 Hz), enabling a comprehensive search for axion-like dark matter. They set new constraints on how axions might interact with neutrons and protons. For neutrons, they reached a sensitivity that beats previous astrophysical limits in some frequency ranges. For protons, they achieved the best lab-based constraints in specific frequency bands.

This work not only advances the search for dark matter but also opens new frontiers in atomic physics, quantum sensing, and particle physics, offering a powerful new strategy to explore the invisible fabric of the universe.

Do you want to learn more about this topic?

Dark matter local density determination: recent observations and future prospects by Pablo F de Salas and A Widmark (2021)

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