Understanding Quantum Non-Equilibrium Matter: Many-Body Localisation versus Glasses, Theory and Experiment

了解量子非平衡物质：多体定位与眼镜、理论和实验

基本信息

批准号：
EP/R04421X/1
负责人：
Juan Garrahan
金额：
$ 61.82万
依托单位：
University of Nottingham
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2018
资助国家：
英国
起止时间：
2018 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FR04421X%2F1
关键词：
Understanding Quantum Non Equilibrium Matter

项目摘要

Many-body systems comprise everything from simple metals, over complicated organic molecules, all the way to living cells. While their physics can be extremely complex, this complexity is however often mostly irrelevant, as most such systems will - when left alone - thermalise, a process through which most information about their preparation history and their initial state is lost. Think of pouring milk into your coffee or tea: there are many different important individual details describing this process - how fast, how much milk, angle and position of milk jug, milk temperature, and so on. All of those parameters are needed to predict the intricate turbulent pattern seen when one starts stirring the tea. At long time, however, all this complexity is hidden and we see merely a homogeneous brownish liquid. This behaviour is typical of ergodic systems and central to statistical mechanics; it allows us to make concrete predictions about a system given only a handful of parameters such as total energy. Physics knows, however, about exceptions to this behaviour. In particular, in recent years, the phenomenon of many-body localisation (MBL) has emerged as a new paradigm for the absence of thermalisation and non-ergodicity in interacting quantum systems. In these systems, all degrees of freedom become localised by an external disorder, and are therefore partially decoupled from each other and cease to thermalise. In particular, it could be shown that these systems keep a much better local memory of their initial conditions. This peculiar effect might for instance be exploited in the future to design better materials to host quantum bits with reduced decoherence - even if some information leaks into the local environment, it will remain local for much longer. While MBL is a novel quantum effect, in classical systems the paradigm of slow dynamics and non-ergodicity is the glass transition, whereby fluid systems - such as liquids, colloidal suspensions or even granular mixtures - cease to flow and fall out of equilibrium at low temperatures or high densities. Here, we seek support for a new theory-experiment collaboration between Nottingham and Cambridge aimed at developing a fundamental understanding of central aspects of non-equilibrium quantum many-body systems. In particular, we propose to establish the connections between MBL and glasses, thereby unveiling new mechanisms for quantum slow relaxation and non-ergodicity, with potential implications for the design and control of novel quantum non-equilibrium materials and devices. Our team comprises researchers with ample experience in experimental and theoretical atomic physics, statistical physics and condensed matter, who have made central contributions to MBL, glasses, open quantum systems, and other topics directly related to this proposal. This joint project will allow us to work hand-in-hand such that new theoretical ideas can quickly be tested in the experiment, which directly feeds back into theoretical developments.

多体系统包括从简单的金属，复杂的有机分子到活细胞的所有内容。尽管它们的物理学可能非常复杂，但是这种复杂性通常大多是无关紧要的，因为大多数这样的系统（当一个单独使用）中，大多数系统会通过该过程，通过该过程，大多数有关其制备历史及其初始状态的信息都会丢失。想想将牛奶倒入您的咖啡或茶中：描述了此过程的许多重要的个人细节 - 牛奶壶的牛奶，角度和位置的速度，牛奶温度等等。所有这些参数都需要预测当人们开始搅拌茶时看到的复杂的湍流图案。然而，长期以来，所有这些复杂性都被隐藏了，我们只是看到一种均匀的褐色液体。这种行为是厄贡系统的典型特征，是统计力学的核心。它使我们能够对系统进行具体预测，仅给出少数参数，例如总能量。但是，物理学知道这种行为的例外。特别是，近年来，多体定位（MBL）的现象已成为一种新的范式，因为它们在相互作用的量子系统中没有热量和非熟练度。在这些系统中，所有的自由度都被外部疾病所定位，因此彼此部分脱钩并停止进行热力。特别是，可以证明这些系统可以更好地对其初始条件的本地记忆更好。例如，将来可能会利用这种特殊的效果来设计更好的材料来托管具有降低的量子位 - 即使某些信息泄漏到当地环境中，它也将保持更长的时间。尽管MBL是一种新颖的量子效应，但在经典系统中，缓慢的动力学和非连接性的范式是玻璃转变，因此流体系统（例如液体，胶体悬浮液甚至颗粒混合物）在低温或高密度下停止流动并从平衡中掉落。在这里，我们寻求支持诺丁汉和剑桥之间的新理论经验合作，旨在对非平衡量子多体系统的中心方面进行基本理解。特别是，我们建议建立MBL与玻璃之间的连接，从而揭示了量子缓慢松弛和非连接性的新机制，对新型量子非平衡材料和设备的设计和控制具有潜在的影响。我们的团队由研究人员组成，具有丰富的实验和理论原子物理学，统计物理和凝结物质，他们对MBL，眼镜，开放量子系统和其他与该建议直接相关的主题做出了核心贡献。这个联合项目将使我们能够齐头并进，以便可以在实验中快速测试新的理论思想，该实验直接反馈理论发展。