AION: A UK Atom Interferometer Observatory and Network

Aion项目利用新一代量子传感器进行基础物理实验，例如发现暗物质，并探测迄今未知的引力波来源，例如遥远宇宙中的剧烈碰撞，以及宇宙只有零点几秒的时候发生的事件。暗物质最可能的候选者之一是某种非常轻的粒子，它以随时间变化的不同密度散布在整个空间中。Aion能够使用基于量子干涉效应的技术来检测这些变化对冷原子的影响，比目前的实验具有更高的灵敏度。同样的量子技术探测引力波通过引起的时空结构的微小波动，AION将在与现有实验LIGO和Virgo不同的波长和频率范围内测量这种影响。通过这种方式，它将能够观察到质量大得多的黑洞的合并，可能会为星系中心超大质量黑洞的形成提供线索。Aion也可能对宇宙早期产生的引力波很敏感，例如相变或宇宙弦产生的引力波。Aion将在一个由美国和欧洲基于类似量子物理的探测器组成的网络中运行，其测量结果将补充LIGO、Virgo和未来的空间实验Lisa的测量结果，通过联合观测提供许多可能的协同效应。我们将在英国建造一台仪器，将基于锶原子的最先进光钟的优点与原子干涉测量相结合。这台仪器有两个原子干涉仪，一个在另一个之上，在一个超过10米高的真空系统中，激光垂直穿过两个原子干涉仪，分裂和重组原子波包。两个原子云将沿着一个长的垂直真空管在不同的高度准备好，两个原子云将被发射，使它们在静止和在重力下落下之前向上飞行几米。这样的“原子喷泉”允许长时间的测量和干涉仪两臂之间的大间隔。原子必须冷却到非常低的温度，在我们的最终设计中低于1纳米开尔文，否则它们会扩散开来，在跌落到探测区域之前变得过于稀薄。一种垂直的激光束，在不同的高度穿过两个原子云，使得差动测量中的共模噪声抑制可以确定重力梯度，其不确定度为1x10^-10/s，可与最先进的技术相媲美。原子在侧臂中冷却，传输到垂直管中，发射，受到形成干涉仪的多个激光脉冲，最后使用激光进行探测。这需要一套非常精密的激光器。这将是英国第一台大规模原子干涉仪；目前在美国、德国和中国有1000万台设备。AION计划利用STFC和EPSRC科学以及量子技术、计算和计量等战略领域之间的协同效应。它汇集了一个由实验和理论粒子物理学家组成的联盟，以及天体物理学家和仪器专家、量子信息科学家、基于锶的原子钟研究专家以及来自STFC和EPSRC社区的原子物理学家。AION将与美国费米实验室等领先的国际实验室合作，建立新的科学伙伴关系，并与空间科学界的成员建立新的科学伙伴关系。AION的量子技术在导航和石油钻探等多个领域具有潜在的应用前景。我们将与英国量子技术中心在传感器和计量学方面密切合作，开发这些技术并将其推向市场。

The AION project harnesses a new generation of quantum sensors to conduct experiments in fundamental physics, such as the discovery of dark matter, and detect hitherto unknown sources of gravitational waves, such as violent collisions far away in the universe and events that occurred when the universe was a fraction of a second old. One of the foremost candidates for dark matter is some type of very light particle that is spread throughout space with a varying density that changes in time. AION is capable of detecting the effects of these variations on cold atoms using techniques based on quantum interference effects, with much greater sensitivity than current experiments. The same quantum techniques probe small fluctuations in the fabric of space-time caused by the passage of gravitational waves, and AION will measure such effects in a different range of wavelength and frequency from the existing experiments LIGO and Virgo. In this way it will be able to observe the mergers of black holes that are much more massive, possibly casting light on the formation of the supermassive black holes at the centres of galaxies. AION may also be sensitive to gravitational waves generated in the very early universe, for example by phase transitions or by cosmic strings. AION will be operated in a network with detectors in the US and Europe that are based on similar quantum physics, and its measurements will complement those by LIGO, Virgo and the future space experiment LISA, providing many possible synergies through joint observations.We will build an instrument in the UK that brings together the advantages of state-of-the-art optical clocks based on Sr atoms, with atom interferometry. This instrument has two atom interferometers, one above the other, in a vacuum system over 10m tall, with a laser beam running vertically through both that splits and recombines atomic wave packets. Two clouds of atoms will be prepared at different heights along a long vertical vacuum pipe, and both clouds will be launched so that they travel upwards for several metres before coming to rest and falling back down under gravity. Such 'atomic fountains' allow a long measurement time and large separation between the two arms of the interferometers. The atoms must be cooled to very low temperatures, less than 1 nanokelvin in our final design, otherwise they spread out and become too dilute before falling through the detection region. A vertical laser beam that runs through both clouds of atoms, at different heights, such that common-mode rejection of noise in differential measurements can determine the gradient of gravity with an uncertainty of 1x10^-10 per shot, comparable with the state of the art. The atoms are cooled in side-arms, transported into the vertical tube, launched, subjected to multiple laser pulses that form the interferometer and then finally detected using laser light. This requires a very sophisticated set of lasers. This will be the first large-scale atom interferometer in the UK; there are currently 10m devices in the USA, Germany and China.The AION programme exploits synergies between STFC and EPSRC science and the strategic areas of quantum technology, computing and metrology. It brings together a consortium of experimental and theoretical particle physicists, as well as astrophysicists and instrumentation experts, quantum information scientists, experts in Sr based atomic clock research, and atomic physicists drawn from the STFC and EPSRC communities. AION will collaborate with leading international laboratories such as Fermilab in the US, creating new scientific partnerships also with members of the space science community. The quantum technologies of AION have potential applications in such varied areas as navigation and oil drilling. We will work closely with the UK Quantum Technologies Hub in sensors and metrology to develop these technologies and bring them to market.