QuDeGPM - Quantum-Degenerate Gases for Precision Measurements

原子干涉已经应用于许多开创性的实验中，从基础研究到精密测量。激光冷却和囚禁技术使宏观物质波的亮源得以实现。合作研究项目QuDeGPM的中心目标是在这一专业知识的基础上，利用量子简并宏观物质波的干涉进行新一代精密测量。设想了两组应用：(1)精确确定自由空间中的基本常量和惯性力；(2)将接近表面的捕获原子的干涉仪用作显微镜，在μm尺度上高灵敏地测量表面力。为了达到最终的灵敏度，我们将设计原子之间的相互作用，并创建非经典物质波量子态，以打破标准的量子测量极限。超冷简并量子气体具有内在的相干性和在空间和动量上的窄扩散，有望成为精密物质波干涉实验的理想起点，类似于用于光光学的激光。与光相反，原子之间相互作用，而简并量子气体的物理学在许多情况下是由这些相互作用主导的。这可能是一个优点，允许使用像压缩这样的非线性光学技巧来提高灵敏度，但也可能是一个缺点，由于不受控制的碰撞相移导致额外的去相移。我们将利用费什巴赫共振控制这些相互作用的最新进展，找出这些相互作用的优点，并抑制这些相互作用造成的缺点。该项目的主要目标是(I)利用量子简并气体进行精密原子干涉测量，(Ii)使用量子简并气体进行精密表面探测，以及(Iii)探索、实现和测试非经典物质波态的新测量方案。

Atom interference has been applied in many pioneering experiments ranging from fundamental studies to precision measurements. The techniques of laser cooling and trapping have allowed the realization of bright sources of macroscopic matter waves. The central goal of the Collaborative Research Project QuDeGPM is to build on this expertise and use interference of quantum degenerate macroscopic matter waves for a new generation of precision measurements.Two sets of applications are envisioned: (1) Precision determination of fundamental constants and inertial forces in free space, and (2) Interferometers for trapped atoms close to the surface as a microscope for highly sensitive measurements of surface forces on μm length scale. To achieve the ultimate sensitivity we will engineer the interactions between the atoms and create non-classical matter-wave quantum states to beat the standard quantum measurement limit.Ultracold degenerate quantum gases with their inherent coherence and narrow spread in space and momentum promise to be the ideal starting point for precision matter wave interference experiments, similar to lasers for light optics. In contrast to light, atoms interact with each other, and the physics of degenerate quantum gases is in many cases dominated by these interactions. This can be an advantage, allowing tricks from non-linear optics like squeezing to boost sensitivity, and a disadvantage, resulting in additional dephasing due to uncontrolled collisional phase shifts. We will exploit recent advances in controlling these interactions by Feshbach resonances to pick out the advantages and to suppress the disadvantages caused by the interactions. The project is organized along the main objectives of (i) performing precision atom interferometry with quantum degenerate gases, (ii) using quantum degenerate gases for precision surface probing, and (iii) exploring, realizing, and testing novel measurement schemes with non-classical matter wave states.