Signatures of Dark Matter: molecular detectors of oscillating fundamental constants

虽然暗物质（DM）在宇宙中比普通物质丰富得多，但在实验室实验中还没有发现它的存在。该项目旨在开展一项实验，该实验将对某些暗物质特征敏感。暗物质可能部分由低质量粒子组成（在neV/c^2范围内）。它可以表现为一个以康普顿频率振荡的场，与标准模型（SM）场耦合。这将导致基本常数振荡，例如精细结构常数、夸克质量、强作用力的耦合常数。在这个项目中，我们考虑分子中的振动跃迁。它们对电子质量、原子核质量和精细结构常数很敏感。通过核质量，也依赖于夸克质量和强作用力的耦合常数。所研制的仪器将用于在室温分子气体中寻找振动跃迁频率的振荡。在1.5µm的乙炔（C2H2）激光光谱将用于此目的。光学谐振器的谐振频率将被用作参考频率。这个实验将在几个方面进行优化。将研究一个非常大的康普顿频率范围（10 Hz - 100 MHz），将使用两种光谱变化，将实现灵敏度的射击噪声水平，有利地选择分子跃迁，相关技术将允许抑制干扰，实验将记录长达1年的测量时间内的大量数据。在项目结束时，我们期望将DM场与SM场的耦合强度上限降低100到1000倍。

Although dark matter (DM) is much more abundant in the universe than normal matter, it has not yet been detected beyond doubt in laboratory experiments. This project aims to develop an experiment that will be sensitive to certain dark matter signatures. Dark matter could consist partly of particles of low mass (in the range neV/c^2). It could behave as a field oscillating at the Compton frequency, coupling to the Standard Model (SM) fields. This would result in oscillating fundamental constants, e.g. the fine structure constant, the quark masses, the coupling constant of the strong force. In this project we consider vibrational transitions in molecules. These are sensitive to the electron mass, the nuclear mass, and the fine structure constant. Via the nuclear mass, there is also a dependence on the quark masses and the coupling constant of the strong force. The apparatus to be developed will be used to search for oscillations in the frequency of vibrational transitions in a room-temperature molecular gas. Laser spectroscopy at 1.5 µm of acetylene (C2H2) will be used for this purpose. The resonance frequency of an optical resonator will be used as a reference frequency. The experiment will be optimised in several respects. A very large Compton frequency range will be investigated (10 Hz - 100 MHz), two spectroscopy variants will be used, the shot noise level of sensitivity will be achieved, the molecular transition is advantageously chosen, a correlation technique will allow the suppression of interferences, and the experiment will record extensive data over up to 1 year of measurement time. At the end of the project, we expect to achieve a reduction of the upper limits for the coupling strength of a DM field to the fields of the SM by factors between 100 and 1000.