An optical frequency comb to support the quantum technology for fundamental physics programme

尽管在理解自然的最基本层面上取得了巨大的成功，从宇宙中最微小的组成部分到最大的结构，我们的知识仍然存在巨大的差距。我们不能在量子水平上理解引力。宇宙中的大部分物质都是一些看不见、未知的物质，我们称之为暗物质。宇宙的膨胀正在加速，受到一种我们称之为暗能量的未知力量的驱动。关于量子引力、暗物质和暗能量的理论很多，但很少有实验证据来支持或区分它们。基于量子科学和技术的最新发展的几个新实验旨在揭示这些谜团。例如，许多量子引力、暗物质和暗能量理论预测，自然界的基本常量，如电子质量除以质子质量，实际上应该在空间或时间上发生变化。这一预测可以通过比较基于不同原子和分子的不同时钟的滴答率来检验，并观察这种情况是否会随着时间的推移而变化。英国正在建立这样一个精密时钟网络，这些时钟发展得很好。为了比较不同的时钟，我们需要一件至关重要的设备。这种设备被称为光学频率梳。它是一种发射数以千计的频率分量的激光器，这些频率分量完全均匀分布。每个分量的频率可以被确定到极高的精度。这是一个工具，它告诉我们一个时钟的频率与另一个时钟的频率是如何比较的，以及这个频率比是否随着时间的推移而变化。值得注意的是，在频率梳的帮助下，时钟甚至不需要位于相同的位置-它们可以通过光纤网络进行比较。这项提议的目的是获得频率梳，以便我们正在建设的量子技术能够发挥其潜力，测试基础物理的基础，并发现什么存在于我们当前知识的限制之外。

Despite the tremendous successes in understanding Nature at its most fundamental level, from the tiniest constituents to the largest structures in the Universe, there remain great gaps in our knowledge. We do not understand gravity at the quantum level. Most of the matter in the Universe is some invisible and unknown substance that we call dark matter. And the expansion of the Universe is accelerating, driven by some unknown force that we call dark energy. There are many theories of quantum gravity, dark matter and dark energy, but little experimental evidence to support them or distinguish between them. Several new experiments based on the latest developments in quantum science and technology aim to shed light on these mysteries. For example, many theories of quantum gravity, dark matter and dark energy predict that fundamental constants of nature, such as the electron mass divided by the proton mass, should actually vary in space or time. This prediction can be tested by comparing the tick rate of different clocks, based on different atoms and molecules, and looking to see whether this changes over time. A network of such precise clocks is being built in the UK, and these clocks are developing well. There is a crucial piece of equipment we need in order to compare different clocks. This equipment is known as an optical frequency comb. It is a laser that emits thousands of frequency components that are perfectly uniformly spaced. The frequency of every component can be determined to extremely high precision. This is the tool that tells us how the frequency of one clock compares to the frequency of another, and whether this frequency ratio is changing over time. Remarkably, with the help of the frequency comb, the clocks do not even need to be at the same location - they can be compared across an optical fibre network. The aim of this proposal is to acquire the frequency comb so that the quantum technologies we are building can fulfil their potential for testing the foundations of fundamental physics and discovering what lies beyond the limits of our current knowledge.