第一作者：Saarik Kalia
发表刊物：Physical Review D
关键字：Physical Review D 110，115029 悬浮铁磁体可作为超高精度磁强计，因其与外界环境隔绝性极佳，故而具备高品质因数。这类装置可用于搜寻类轴子、暗光子等超轻暗物质候选粒子。轴子 - 光子耦合与动能混合效应会产生真实磁场，而轴子 - 电子耦合则会形成等效磁场（即 “轴子风”），悬浮铁磁体对这两类场均具备探测能力。 目前，悬浮铁磁体在直流磁场下的动力学特性已得到充分研究，但上述各类耦合效应产生的均为交流场。本文研究了铁磁体对外加交流磁场的响应规律，并据此评估其对轴子暗物质与暗光子暗物质的探测灵敏度。研究重点分析了交流场引发的运动形态：磁矩是绕外场进动（类似电子自旋），还是在场平面内摆动（类似指南针）。分析表明，现有悬浮铁磁体实验装置对轴子 - 电子耦合的探测灵敏度，已可与共磁强计、扭秤实验持平。对于暗物质质量满足 mDM ≲ feV的超轻暗物质，下一代装置有望成为探测轴子 - 电子耦合、暗光子动能混合以及轴子 - 光子耦合的高灵敏工具。 Levitated ferromagnets act as ultraprecise magnetometers, which can exhibit high quality factors due to their excellent isolation from the environment. These instruments can be utilized in searches for ultralight dark matter candidates, such as axionlike dark matter or dark-photon dark matter. In addition to being sensitive to an axion-photon coupling or kinetic mixing, which produce physical magnetic fields, ferromagnets are also sensitive to the effective magnetic field (or “axion wind”) produced by an axion-electron coupling. While the dynamics of a levitated ferromagnet in response to a dc magnetic field have been well studied, all of these couplings would produce ac fields. In this work, we study the response of a ferromagnet to an applied ac magnetic field and use these results to project their sensitivity to axion and dark-photon dark matter. We pay special attention to the direction of motion induced by an applied ac field, in particular, whether it precesses around the applied field (similar to an electron spin) or librates in the plane of the field (similar to a compass needle). We show that existing levitated ferromagnet setups can already have comparable sensitivity to an axion-electron coupling as comagnetometer or torsion balance experiments. In addition, future setups can become sensitive probes of axion-electron coupling, dark-photon kinetic mixing, and axion-photon coupling, for ultralight dark matter masses mDM ≲ feV.
卷号：110
发布期刊链接：https://journals.aps.org/prd/abstract/10.1103/PhysRevD.110.115029
合写作者：Dmitry Budker,Derek F. Jackson Kimball,Wei Ji,Zhen Liu,Alexander O. Sushkov,Chris Timberlake,Hendrik Ulbricht,Andrea Vinante,Tao Wang