Search for novel collective phenomena due to many-body correlations in low dimensional systems

寻找低维系统中多体相关性引起的新集体现象

• 批准号: RGPIN-2019-05486
• 负责人: Maiti, Saurabh
• 金额: $ 1.75万
• 依托单位: Concordia University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=762525
• 关键词: Search; novel; collective; phenomena; due

Low dimensional systems are interesting class of systems exhibiting novel quantum phenomena. Some examples that has created a lot of buzz are unconventional superconductors and Graphene-based materials. They offer great promise for the future by aiding in discovery on novel quantum phases (involving magnetism, density waves, superconductivity and even coexistence amongst them); and replacing electronics with Spintronics: a more efficient means to transfer information. Another unavoidable ingredient in low dimensional systems is the spin-orbit coupling that breaks parity. When combined with superconductivity it can lead to exotic excitations like Majorana fermions which are essential for quantum computing. However, much of the excitement has been at the level of single-particle physics. This does not allow us to exploit the benefits of the quantum world to the fullest potential. To do that one needs to understand the role of many-body correlations in such systems. This research program is designed to achieve precisely that in a very systematic manner by studying collective excitations in various low-dimensional systems. Collective excitations in general have the potential to tell us a great deal about a system provided we are equipped with a theory that can appropriately handle correlations. As part of this program, we will investigate the role of electronic correlations on spin-orbit coupled single/bilayer Graphene grown on transition metal dichalcogenides. It provides us with the opportunity to investigate collective excitations from non-spin degrees of freedom like sublattice, valley, and layer. We will further investigate collective excitations in the various quantum phases expected around the unconventional superconductivity phase like nematic, coexistence of nematic with superconductivity, magnetic and its coexistence with superconductivity. We will also provide the theory of Raman spectrum in all of these phases. Experimentally tracking the modes across the phase-boundaries using our theoretical model will provide improved insight into the nature of correlations present in the system. This program is designed to develop theoretical tools to handle many-body correlations in spin-orbit coupled systems: an important step forward in studying more complex phases of matter and incorporating many-body effects into fields like Spintronics and quantum computation. Several groups stand to benefit from the output of this program: it directly impacts groups working on Graphene-based devices; the high Tc community can benefit from the fact that different pairing mechanisms that predict similar ground-states, can now be distinguished as the collective excitations are different in each case; many of the conclusions we form in this program can also be tested using cold-atom set-ups thereby encouraging experiments in that field; the knowledge of collective excitations is also a stepping stone towards gauging the properties of non-equilibrium systems.

低维系统是一类有趣的系统，表现出新颖的量子现象。一些引起广泛关注的例子是非常规超导体和石墨烯基材料。它们通过帮助发现新的量子相（涉及磁性、密度波、超导性，甚至它们之间的共存），为未来带来了巨大的希望；用自旋电子学取代电子学：一种更有效的信息传输方式。低维系统中另一个不可避免的因素是破坏宇称的自旋轨道耦合。当与超导性结合时，它可以产生奇异的激发，例如马约拉纳费米子，这对于量子计算至关重要。然而，大部分令人兴奋的事情都发生在单粒子物理学的层面上。这不允许我们充分发挥量子世界的优势。为此，我们需要了解多体关联在此类系统中的作用。该研究计划旨在通过研究各种低维系统中的集体激励，以非常系统的方式精确地实现这一目标。一般来说，只要我们配备了能够适当处理相关性的理论，集体激励就有可能告诉我们很多有关系统的信息。 作为该计划的一部分，我们将研究电子相关性对在过渡金属二硫属化物上生长的自旋轨道耦合单/双层石墨烯的作用。它为我们提供了研究亚晶格、谷和层等非自旋自由度的集体激发的机会。我们将进一步研究非常规超导相周围预期的各种量子相的集体激发，如向列相、向列相与超导性的共存、磁性及其与超导性的共存。我们还将提供所有这些阶段的拉曼光谱理论。使用我们的理论模型对跨相边界的模式进行实验跟踪将有助于更好地洞察系统中存在的相关性的本质。 该项目旨在开发理论工具来处理自旋轨道耦合系统中的多体相关性：这是研究更复杂的物质相并将多体效应纳入自旋电子学和量子计算等领域的重要一步。多个团体将从该计划的成果中受益：它直接影响研究基于石墨烯的设备的团体；高 Tc 社区可以受益于这样一个事实：预测相似基态的不同配对机制现在可以区分，因为每种情况下的集体激发都不同；我们在该计划中得出的许多结论也可以使用冷原子装置进行测试，从而鼓励该领域的实验；集体激励的知识也是衡量非平衡系统特性的垫脚石。