Quantum-Degenerate Gases for Precision Measurements (QuDeGPM)

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。该项目是EUROCORES合作研究项目(在欧洲科学基金会协调的EuroQUASAR方案范围内)的一部分，该项目的目标是在这一专门知识的基础上，利用量子简并宏观物质波的干扰进行新一代精确测量。设想了两组应用：(1)精确确定自由空间中的基本常数和惯性力；(2)用于接近表面的捕获原子的干涉仪，作为一种显微镜，用于在微米长度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，以超过标准的量子测量极限。超冷简并量子气体由于其固有的相干性以及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。许多计划中的工作将是非常基础和探索性的，因为许多能力以及可能的限制还有待研究。名为用于精密测量的量子简并气体(QudeGPM)的合作研究项目将欧洲的努力集中在利用量子简并气体，特别是玻色-爱因斯坦凝聚体(BEC)进行精确测量上。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。达勒姆的这个项目专注于使用具有可调相互作用的物质波来探测原子表面的相互作用。具体地说，计划进行两次试验性推进。第一种是使用明亮的物质波孤子作为新形式的物质波干涉计量学的基础。这项工作与2008年1月开始的一个现有项目(EPRSC赠款EP/F002068/1)相联系。第二个推力利用凝聚体，在凝聚体中相互作用被调到零，以研究固体表面附近一维晶格中的长寿命Bloch振荡。

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. This project is part of a EUROCORES Collaborative Research Project (within the EuroQUASAR programme coordinated by ESF) whose goal is to build upon 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 the micron 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. Much of the planned work will be very fundamental and exploratory as many of the capabilities together with possible limitations have yet to be investigated.The collaborative research project entitled Quantum-Degenerate Gases for Precision Measurement (QuDeGPM) focuses European efforts on precision measurements with quantum degenerate gases and in particular with Bose-Einstein condensates (BEC). 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. The project in Durham focuses on the use of matter-waves with tunable interactions to probe atom surface interactions. Specifically two experimental thrusts are planned. The first uses bright matter-wave solitons as the basis for a new form of matter-wave interferometry. This work connects to an existing project which began in January 2008 (EPRSC grant EP/F002068/1). The second thrust exploits condensates where the interactions are tuned to zero to study long-lived Bloch oscillations in a 1D lattice in the vicinity of a solid surface.