Long-range interaction using strontium atoms in an optical lattice

量子传感器提供了前所未有的精度和准确性，并且在大多数情况下都超过了它们的经典对应部件。例如，光学钟已经达到了前所未有的精度~1*10-18，这是使用传统机械振荡器无法想象的。其背后的基本思想是将原子捕获并冷却到超低温。现在的重点是将这些经过验证的概念转化为具有实际应用价值的紧凑、坚固和节能的传感器。这种阶跃变化需要高效且控制良好的原子源和最佳的检测技术。在我们的实验室里，我们经常将数百万个锶原子冷却到微开尔文的温度。在这些量子传感器中，原子粒子噪声是实现最终精度的基本障碍之一。在我们的实验中，我们的目标是使用3P0-3D1跃迁，以便在不同晶格位置[1]的Sr原子之间产生纠缠。这种纠缠是由一个大的感应偶极矩（>3.5Debye）引起的。纠缠N个原子将使原子传感器的精度提高4倍。在这个项目中，检测技术将发挥至关重要的作用。因此，我们将探索各种检测方案的实施。除了测量不同状态下的相对粒子数和几微米量级的空间分辨率的“原位”荧光测量外，我们还将研究光在光学晶格原子上的布拉格散射作为识别小尺度周期结构的手段。我们还将研究飞行时间成像技术，以确定样品动量分布的模式。事实上，噪声相关方法对于识别晶格中的相位也是非常有用的。在该项目中，将有机会获得真空室，激光器，光接口和计算机控制方面的经验和专业知识。

Quantum sensors provide unprecedented precision & accuracy, and are surpassing their classical counter parts in most of the cases. For instance, optical clocks have already reached the unprecedented precision ~1*10-18, which is unthinkable using conventional mechanical oscillators. The underpinning idea behind is about trapping and cooling of atoms to ultra low temperatures. Now thrust is on to translating these proven concepts into compact, robust and energy efficient sensors with real world applications. Such a step change demands an efficient and well-controlled atom source and optimal detection techniques. In our lab, we routinely cool millions of Sr atoms to micro Kelvin temperature. Atom shot noise is one of the fundamental barriers to an ultimate achievable precision in these quantum sensors. In our experiment, we aim to use the 3P0-3D1 transition in order to create entanglement between Sr atoms at different lattice sites [1]. This entanglement is caused by a large induced dipole moment (>3.5Debye). Entangling N atoms will increase the precision of an atomic sensor by factor of sqrt N. In this project, detection techniques will play a crucial role. Therefore, we will explore the implementation of various detection schemes. In addition to measurements of the relative particle numbers in different states and 'in-situ' fluorescence measurements with spatial resolution on the order of a few micro, we will study the use of Bragg-scattering of light on the atoms in the optical lattice as a means to identify small-scale periodic structures. We will also study time-of-flight imaging techniques to identify patterns in the momentum distribution of the sample. In fact, noise correlation methods are also very useful to identify the phases in a lattice. Within the project, there will be an opportunity to gain experience and expertise on vacuum chamber, lasers, optical-interface and computer control.