Quantum Universe

量子宇宙

• 批准号: RGPIN-2020-04316
• 负责人: Turok, Neil
• 金额: $ 3.64万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=716391
• 关键词: Quantum; Universe

The universe arrayed around us provides a marvellous natural physics laboratory. As we look outwards, we see amazing objects like neutron stars and black holes, undergoing extreme physical processes in which the fundamental laws of physics play out in front of our eyes. We see galaxies and stars in the process of forming, developing and aging. We detect the light, radio waves, X--rays, neutrinos and even gravitational waves emitted from each of these, and many other dramatic sources. Seen from our viewpoint outside them, black holes are extremely simple yet paradoxical objects. Reconciling them with quantum physics could lead to revolutionary advances in our understanding of space and time. Observed from our vantage point within it, the universe is likewise remarkably minimal in form, yet equally puzzling. Physics' greatest challenge is to understand this simplicity. To do so we must combine the laws of quantum physics, which are extremely well verified in laboratory experiments, with Einstein's theory of gravity, which accurately describes the structure and evolution of the cosmos. This proposal will support an exceptional cohort of students working to develop Feynman's famous path integral formulation of quantum mechanics with the inclusion of gravity. The proposer pioneered the use of Picard--Lefschetz theory, an advanced mathematical technique, in combination with ideas such as weak measurement, coming from quantum foundations, and geometrodynamics - the description of quantum spacetime. These approaches will be combined in a fully quantum description, to understand how classical spacetime emerges from constructive interference and how quantum fluctuations perturb its fabric. One PhD student will work on each of the following objectives. O1: proving the existence of Feynman's path integral for real-time quantum systems, both with and without gravity, and applying this to various systems, O2: modelling the interference patterns produced by coherent sources such as pulsars and fast radio bursts and attempting to reconstruct the source and the lens, O3: studying the quantum behaviour of spacetime including the big bang singularity, the emergence of time and the quantum evaporation of black holes, and O4: developing our recent explanation the simplest yet proposed - for the cosmological dark matter. The latter rests on imposing a profound symmetry (CPT symmetry) on the vacuum state of the neutrino sector of the standard model of particle physics. Comparison with leading edge observations and predictions for new experiments will be a hallmark of our work. Our overarching goal is to obtain a consistent quantum understanding of the universe, across all scales, consistent with the known laws of physics as established through experiment and observation. The powerful mathematical tools and techniques we develop are likely to have wide application, for example assisting with the design and data analysis tasks of revolutionary new radio telescopes.

我们周围的宇宙提供了一个奇妙的自然物理实验室。当我们向外看时，我们会看到中子星和黑洞等神奇的物体，它们经历着极端的物理过程，在这些过程中，物理学的基本定律就在我们眼前上演。我们看到星系和恒星在形成、发展和老化的过程。我们探测到光、无线电波、X射线、中微子甚至引力波，以及其他许多引人注目的来源。从我们置身黑洞之外的角度来看，黑洞是极其简单却又自相矛盾的物体。将它们与量子物理学相结合，可能会给我们对空间和时间的理解带来革命性的进步。从我们在宇宙内部的有利位置观察，宇宙的形状同样非常小，但同样令人费解。物理学最大的挑战是理解这种简单性。要做到这一点，我们必须将量子物理定律与爱因斯坦的引力理论结合起来，量子物理定律在实验室实验中得到了非常好的验证，爱因斯坦的引力理论准确地描述了宇宙的结构和演化。这项提案将支持一群特殊的学生，他们致力于发展费曼著名的包含重力的量子力学路径积分公式。这位提出者率先使用了皮卡德-莱夫谢茨理论，这是一种先进的数学技术，结合了弱测量等思想，来自量子基础，以及几何动力学——量子时空的描述。这些方法将结合在一个完全的量子描述中，以理解经典时空是如何从建设性干涉中产生的，以及量子涨落是如何扰乱其结构的。一名博士生将分别研究以下目标。O1：证明实时量子系统的费曼路径积分的存在性，无论是否有重力，并将其应用于各种系统；O2：模拟脉冲星和快速射电暴等相干源产生的干涉模式，并试图重建源和透镜；O3：研究时空的量子行为，包括大爆炸奇点，时间的出现和黑洞的量子蒸发；O4：发展我们最近提出的最简单的解释——宇宙暗物质。后者依赖于在粒子物理标准模型的中微子部分的真空状态上施加一种深度对称（CPT对称）。与前沿观察和新实验的预测进行比较将是我们工作的一个标志。我们的首要目标是获得对宇宙的一致的量子理解，跨越所有尺度，与通过实验和观察建立的已知物理定律一致。我们开发的强大的数学工具和技术可能有广泛的应用，例如协助革命性的新型射电望远镜的设计和数据分析任务。