Campbell William M, McAllister Ben T, Goryachev Maxim, Ivanov Eugene N, Tobar Michael E
ARC Centre of Excellence for Engineered Quantum Systems and ARC Centre of Excellence for Dark Matter Particle Physics, Department of Physics, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
Phys Rev Lett. 2021 Feb 19;126(7):071301. doi: 10.1103/PhysRevLett.126.071301.
We present a way to search for light scalar dark matter (DM), seeking to exploit putative coupling between dark matter scalar fields and fundamental constants, by searching for frequency modulations in direct comparisons between frequency stable oscillators. Specifically we compare a cryogenic sapphire oscillator (CSO), hydrogen maser (HM) atomic oscillator, and a bulk acoustic wave quartz oscillator (OCXO). This work includes the first calculation of the dependence of acoustic oscillators on variations of the fundamental constants, and demonstration that they can be a sensitive tool for scalar DM experiments. Results are presented based on 16 days of data in comparisons between the HM and OCXO, and 2 days of comparison between the OCXO and CSO. No evidence of oscillating fundamental constants consistent with a coupling to scalar dark matter is found, and instead limits on the strength of these couplings as a function of the dark matter mass are determined. We constrain the dimensionless coupling constant d_{e} and combination |d_{m_{e}}-d_{g}| across the mass band 4.4×10^{-19}≲m_{φ}≲6.8×10^{-14} eV c^{-2}, with most sensitive limits d_{e}≳1.59×10^{-1}, |d_{m_{e}}-dg|≳6.97×10^{-1}. Notably, these limits do not rely on maximum reach analysis (MRA), instead employing the more general coefficient separation technique. This experiment paves the way for future, highly sensitive experiments based on state-of-the-art acoustic oscillators, and we show that these limits can be competitive with the best current MRA-based exclusion limits.
我们提出了一种寻找轻标量暗物质（DM）的方法，试图通过在频率稳定振荡器的直接比较中寻找频率调制，来利用暗物质标量场与基本常数之间的假定耦合。具体而言，我们比较了低温蓝宝石振荡器（CSO）、氢脉泽（HM）原子振荡器和体声波石英振荡器（OCXO）。这项工作首次计算了声学振荡器对基本常数变化的依赖性，并证明它们可以成为标量暗物质实验的灵敏工具。基于HM和OCXO之间16天的数据比较以及OCXO和CSO之间2天的比较给出了结果。未发现与标量暗物质耦合一致的基本常数振荡迹象，而是确定了这些耦合强度随暗物质质量的函数限制。我们在4.4×10⁻¹⁹≲m_φ≲6.8×10⁻¹⁴ eV c⁻²的质量范围内约束无量纲耦合常数d_e和组合|d_m_e - d_g|，最灵敏的限制为d_e≳1.59×10⁻¹，|d_m_e - d_g|≳6.97×10⁻¹。值得注意的是，这些限制不依赖于最大可达性分析（MRA），而是采用更通用的系数分离技术。该实验为未来基于最先进声学振荡器的高灵敏度实验铺平了道路，并且我们表明这些限制可以与当前基于MRA的最佳排除限制相竞争。
