Super-Diffusion In Quantum Spin Chains

量子自旋链中的超扩散

• 批准号: EP/X011887/1
• 负责人: Mingee Chung
• 金额: $ 42.74万
• 依托单位: University of Birmingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FX011887%2F1
• 关键词: Super; Diffusion; Quantum; Spin; Chains

A drop of ink in a glass of water will diffuse outwards with time, eventually colouring the whole of the water homogeneously. A ball on a billiard board, on the other hand, will roll around, colliding and scattering off other balls. Transport of mass, energy or other properties in nature seem to occur predominantly in either way, called diffusive and ballistic, respectively. They constitute our intuition into the natural world and universe. However, physicists suspect that there could be other new types of transport defying our common sense. For instance, the transport of magnetic fluctuations in certain materials could occur neither diffusively nor ballistically, but somewhat intermediate. This unconventional transport is called the super-diffusion and is predicted to occur in one-dimensional quantum magnetic materials. It is also exciting that such unconventional transport could occur at room temperature in contrast with our naïve expectation that unique behaviour from quantum systems should be only observed at extremely low temperature. This could be a useful aspect for potential application such as in Spnitronics. In this research project, I aim to provide the first clear experimental evidence for super-diffusion in quantum magnets. More specifically, I will look into crystals where magnetic ions are predominantly coupled along one direction, rather than three directions. This allows the crystals essentially behave as a collection of one-dimensional chain of magnetic ions. I will use Nuclear Magnetic Resonance (NMR) technique, akin to MRI, to evidence that the transport of magnetic fluctuations in such one-dimensional quantum chain occurs as super-diffusion. Through this research, we will be able to better understand the properties of quantum materials, which will underpin the development of new quantum technologies such as quantum sensors or computers.

一杯水中的一滴墨水会随着时间的推移向外扩散，最终使整个水均匀地着色。另一方面，台球板上的一个球会滚动，碰撞并分散其他球。自然界中的能量或其他性质似乎主要以两种方式发生，分别称为扩散和弹道，它们构成了我们对自然世界和宇宙的直觉。然而，物理学家怀疑可能存在其他违背我们常识的新型运输方式。例如，某些材料中的磁波动传输既不能以扩散方式也不能以弹道方式发生，而是以某种中间方式发生，这种非常规传输被称为超扩散，预计会在一维量子磁性材料中发生。这种非常规的传输可以在室温下发生，这与我们天真的期望相反，即量子系统的独特行为只能在极低的温度下观察到，这对于潜在的应用（例如在自旋电子学中）可能是一个有用的方面。目的是为量子磁体中的超扩散提供第一个明确的实验证据，更具体地说，我将研究磁性离子主要沿一个方向而不是三个方向耦合的晶体，这使得晶体本质上表现为一个集合。我将使用类似于 MRI 的核磁共振 (NMR) 技术来证明这种一维量子链中的磁涨落传输是作为超扩散发生的。有能力的更好地了解量子材料的特性，这将支持量子传感器或计算机等新量子技术的发展。