PM: Optomechanical Dark Matter Detectors

暗物质的起源是我们这个时代经久不衰的科学谜团之一。经过40年的搜索，直接探测到暗物质“粒子”仍然难以捉摸，这促使人们呼吁对搜索空间和探测策略进行全面反思。利用光探测固态物体微小变形的光学机械传感器已经走在了前列，因为它们提供了一系列与原子大小或位置相关的候选暗物质。该项目的目标是建立第一代光学机械暗物质探测器，利用近年来使光学机械系统能够在量子极限下运行的技术。除了基础物理，该项目还将解决量子传感器开发的关键挑战，如可伸缩性和消相干缓解。更广泛的目标是培养对粒子和量子物理有混合兴趣的新一代研究生和博士后，认识到未来的量子劳动力将从广泛的科学背景中受益。具体地说，该项目将与实验者(PI)和理论合作者一起探索使用一系列低温光学机械加速计探测超轻“暗光子”暗物质。每个加速度计都基于频率可调的超高Q氮化硅薄膜，该薄膜耦合到一个光腔。氮化硅薄膜是一种成熟的机械谐振器技术，在毫微电子温度下具有极低的耗散，使其能够在声频率下获得皮克加速度灵敏度。在该项目的这一探索阶段，将在4K低温恒温器中开发一种基于单厘米尺度薄膜的原型探测器。其目标将是在1.e-9到1.e-11 eV质量(1 kHz-100 khz康普顿频率)范围内超越Eöt-Wash扭转天平实验设置的暗光子暗物质的当前限制。更长期的努力，包括一系列以标准量子极限探测的光子晶体薄膜，将以数量级改进为目标，并提供各种基本弱力测试。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The origin of dark matter is one of the enduring scientific mysteries of our time. After four decades of searching, direct detection of a dark matter “particle” remains elusive, spurring calls for a comprehensive rethinking of the search space and detection strategy. Optomechanical sensors, which use light to probe minute deformations of solid-state objects, have emerged at the forefront, as they give access to a broad set of dark matter candidates which couple to the size or position of atoms. The aim of this project is to build a first generation optomechanical dark matter detector, drawing on techniques which have enabled optomechanical systems to operate at the quantum limit in recent years. Beyond fundamental physics, the project will address key challenges to the development of quantum sensors, such as scalability and decoherence mitigation. A broader goal is the education of a new generation of graduate students and postdocs with hybrid interests in particle and quantum physics, recognizing that the future quantum workforce will benefit from drawing upon a wide pool of scientific backgrounds.Specifically, the project will join experimentalists (the PI) and theory collaborators to explore detection of ultralight “dark photon” dark matter using an array of cryogenic optomechanical accelerometers. Each accelerometer is based on a frequency-tunable, ultra-high-Q silicon nitride membrane coupled to an optical cavity. Silicon nitride membranes are a well-established mechanical resonator technology and can have exceptionally low dissipation at millikelvin temperatures, giving access to pico-g acceleration sensitivities at acoustic frequencies. In this exploratory phase of the project, a prototype detector will be developed based on a single centimeter-scale membrane in a 4 K cryostat. The goal will be to eclipsing current constraints on dark photon dark matter in the 1.e-9 to 1.e-11 eV mass (1 kHz – 100 kHz Compton frequency) range set by the Eöt-Wash torsion balance experiments. Longer term efforts, involving an array of photonic crystal membranes probed at the standard quantum limit, will target order of magnitude improvement and give access to a variety of fundamental weak force tests.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.