Extension to the 'Quantum-enhanced Interferometry for New Physics' programme

现代物理学解释了各种令人惊叹的现象，从最小的尺度到最大的尺度，已经彻底改变了世界！激光、半导体和晶体管是我们笔记本电脑、手机和医疗设备的核心。这些技术反过来使我们能够以更详细、更精确和更严谨的方式探索自然界。在过去的几年里，英国和世界各地的国家量子技术计划正在开发新的量子技术，这些技术可能会影响我们的日常生活，并使基础物理研究能够带来新的发现。光的量子状态最近提高了引力波探测器的灵敏度，迄今为止，引力波探测器的探测令公众着迷，超导跃迁边缘传感器现在被用于捕捉高分辨率宇宙图像的望远镜。尽管现代物理学取得了这些成功，但几个深刻而具有挑战性的问题仍然悬而未决。我们的联盟QI扩展将基于量子技术的最新进展，包括我们现有的QI联盟和其他联盟，以解决两个最紧迫的问题：(I)暗物质的本质是什么，以及(Ii)量子力学如何与爱因斯坦的相对论相结合？第一个研究方向是由大量观测推动的，这些观测表明，星系中的相当大一部分物质不是通过光学望远镜直接观测到的。了解这种神秘的所谓暗物质的性质将有助于揭示宇宙的历史，并将引发基础物理学和可能的应用物理学的新研究领域。世界各地的许多最先进的实验都在寻找暗物质候选者，但到目前为止还没有运气。我们建议寻找的候选粒子是轴子和轴子类粒子(ALP)。这些粒子是由粒子物理学中的悬而未决的问题所驱动的，它们可能是暗物质的重要组成部分或全部。首先，我们将提高目前实验的灵敏度，该实验将探测暗物质信号，或者将大范围轴子质量的轴子-光子耦合的现有限制提高几个数量级。其次，我们将建造并表征一个直径为8‘’/200 nm的大尺寸超导纳米线单光子探测器，以扩展暗物质研究。我们的第二条研究线致力于空间和时间的性质。我们有一长串成功的量子力学和爱因斯坦相对论的实验测试。但是，引力应该与量子力学相结合吗？如果是这样的话，是如何做到的呢？就像物理学中的任何悬而未决的问题一样，实验可以引导我们找到答案。为此，我们建议研究时空的两个量子方面。首先，我们将实验研究全息原理，即体积的信息内容可以在其边界上编码。我们将利用光的量子态，建造两个超灵敏激光干涉仪，以前所未有的灵敏度调查空间不同区域之间可能存在的关联。我们还将利用这些数据来寻找银晕中的标量暗物质。第二，我们将寻找近似解决量子引力问题的半经典引力模型的特征。在我们现有的实验测试半经典引力模型工作的基础上，我们将寻求设计桌面实验，这些实验可能提供引力的量子本质的直接签名。借助现代量子技术回答这些具有挑战性的基础物理问题，有可能为物理学研究开辟新的视野，并达到对我们生活的世界的新理解水平。提出的研究方向共享量子增强干涉测量的共同技术平台，并受益于参与研究人员的不同技能。

Modern physics explains a stunning variety of phenomena from the smallest of scales to the largest and has already revolutionized the world! Lasers, semiconductors, and transistors are at the core of our laptops, mobile phones, and medical equipment. These technologies in turn have enabled us to explore the natural world with ever greater detail, precision, and rigour.Over the last few years, novel quantum technologies are being developed within the National Quantum Technology Programme in the UK and throughout the world that could impact our everyday lives and enable fundamental physics research that leads to new discoveries. Quantum states of light have recently improved the sensitivity of gravitational-wave detectors, whose detections to date have enthralled the public, and superconducting transition-edge-sensors are now used in telescopes that capture high-resolution images of the universe.Despite these successes of modern physics, several profound and challenging questions remain open. Our consortium QI-extension will build on recent advances in quantum technologies, both within our existing consortium QI and beyond, to address two of the most pressing questions: (i) What is the nature of dark matter, and (ii) How can quantum mechanics be united with Einstein's theory of relativity?The first research direction is motivated by numerous observations which suggest that a significant fraction of the matter in galaxies is not directly observed by optical telescopes. Understanding the nature of this mysterious so-called dark matter will shed light on the history of the universe and will trigger new areas of research in fundamental and possibly applied physics. A number of state-of-the-art experiments world-wide are looking for dark matter candidates with no luck so far. The candidates we propose to search for are axions and axion-like-particles (ALPs). These particles are motivated by outstanding questions in particle physics and may account for a significant part, or all of dark matter. First, we will enhance the sensitivity of our current experiment that will detect a dark matter signal or improve the existing limits on the axion-photon coupling by a few orders of magnitude for a large range of axion masses. Second, we will build and characterise a large (8''/200 nm diameter) superconducting nanowire single photon detector to extend dark matter searches.Our second line of research is devoted to the nature of space and time. We have a long list of successful experimental tests of quantum mechanics and Einstein's theory of relativity. But should gravity be united with quantum mechanics? If so, how? As with any open question in physics, experiments can direct us towards the answers.To that end, we propose to study two quantum aspects of space-time. Firstly, we will experimentally investigate the holographic principle, which states that the information content of a volume can be encoded on its boundary. We will exploit quantum states of light and build two ultra-sensitive laser interferometers that will investigate possible correlations between different regions of space with unprecedented sensitivity. We will also use the data to search for scalar dark matter in the galactic halo.Secondly, we will search for signatures of semiclassical gravity models that approximately solve the quantum gravity problems. Building on our existing work on experimentally testing semiclassical models of gravity, we will seek to design table-top experiments that may provide direct signatures of the quantum nature of gravity.Answering these challenging questions of fundamental physics with the aid of modern quantum technologies has the potential to open new horizons for physics research and to reach a new level of understanding of the world we live in. The proposed research directions share the common technological platform of quantum-enhanced interferometry and benefit from the diverse skills of the researchers involved.