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EPSRC-SFI: Non-Equilibrium Steady-States of Quantum many-body systems: uncovering universality and thermodynamics (QuamNESS)

EPSRC-SFI：量子多体系统的非平衡稳态：揭示普遍性和热力学 (QuamNESS)

基本信息

批准号：
EP/T028424/1
负责人：
Stephen Clark
金额：
$ 80.81万
依托单位：
University of Bristol
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2020
资助国家：
英国
起止时间：
2020 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FT028424%2F1
关键词：
EPSRC SFI Non Equilibrium Steady

项目摘要

QuamNESS will develop novel mathematical tools and powerful simulations to understand the fundamental principles governing the performance of the smallest possible engines. Miniaturised to only handfuls of atoms, these machines hold the promise of offering highly efficient ways of generating power, managing heat flows and recovering wasted energy in wide-ranging technologies, from microprocessors to chemical reactions. In contrast to conventional engines, the pistons and gears of nanoscale machines are instead the flow of individual particles, such as electrons. By being so small, even a single electron hopping through the engine represents a remarkably disruptive stochastic event. Therefore, the operation of such machines is subject to violent random fluctuations, not dissimilar to a wildly spluttering engine. Moreover, these microscopic constituents of the engine do not behave like everyday objects, but instead obey the laws of quantum mechanics. Both these features make it extremely problematic to define familiar concepts, like heat and temperature, central to the formalism of thermodynamics that so successfully describes conventional engines. Yet such apparently unhelpful complications should rather be seen as unique features of such small machines, presenting a multitude of opportunities to be harnessed. Developing a new framework to unravel these quantum enhancements is of paramount importance and is a core objective of this project.Quantum systems are well known to possess counterintuitive properties. This includes coherence, namely the idea that a particle can be in many places at once as a superposition. When there are many particles interacting, we can also have entanglement - a superposition of different multi-particle configurations - giving rise to novel correlations and spooky action-at-a-distance. Under the right conditions, these strange quantum effects can compete with and radically alter the usual random jittery thermal motion occurring in a system. This project will sharpen our view of this interplay and how it can be harnessed by reassessing the fundamental concepts of irreversibility and fluctuations. Useful engines produce a finite power output. This means they are never as efficient as an ideal infinitely slow engine because they inevitably waste energy as friction during a rapid cycle. The trade-off between power output and efficiency relies on quantifying this waste as irreversible entropy production. Our work will reformulate entropy production in new ways best suited to reveal the contributions of quantum coherence and correlations prevalent at the nanoscale. Further to this, for classical machines entropy production is known to bound the fluctuations in time of the power output. Specifically, to make an engine splutter less at a given power output necessitates increasing entropy production. We will determine the highly non-trivial generalization of this relation to the quantum domain. Simultaneous to this, we will develop sophisticated numerical methods for simulating complex quantum machines composed of many interacting constituents, allowing these crucial properties to be predicted.Our theoretical framework will be high beneficial to current experimental efforts aimed at engineering quantum technologies with super-efficient thermal management. The most pressing applications in this direction will be explored within the scope of this project, including an assessment of novel mechanisms for enhancing quantum thermal machines, the ability to control quantum systems via periodic driving and proposals for experimentally verifying these findings. The bold ambition of this project leverages the synergistic talents of the research team, with PI Clark's expertise in numerical methods complementing the analytical skills of Co-Is Paternostro and Goold.

QuamNESS将开发新颖的数学工具和强大的模拟，以了解最小发动机性能的基本原理。这些机器被缩小到只有少量原子，有望提供高效的发电方式，管理热流，并在从微处理器到化学反应的广泛技术中回收浪费的能量。与传统的发动机不同，纳米机器的活塞和齿轮是单个粒子的流动，比如电子。由于体积如此之小，即使是一个电子在引擎中跳跃，也代表了一个非常具有破坏性的随机事件。因此，这类机器的运行会受到剧烈的随机波动的影响，这与一个疯狂飞溅的发动机没有什么不同。此外，发动机的这些微观组成部分的行为不像日常物体，而是遵守量子力学定律。这两个特征使得定义熟悉的概念非常困难，比如热量和温度，这是热力学形式主义的核心，成功地描述了传统发动机。然而，这种显然无益的复杂性应该被视为这种小型机器的独特功能，提供了大量可以利用的机会。开发一个新的框架来解开这些量子增强是至关重要的，也是这个项目的核心目标。众所周知，量子系统具有违反直觉的性质。这包括相干性，即一个粒子可以作为叠加态同时出现在许多地方。当有许多粒子相互作用时，我们也可以有纠缠-不同多粒子配置的叠加-产生新的关联和幽灵般的远距离作用。在适当的条件下，这些奇怪的量子效应可以与系统中通常发生的随机抖动热运动相竞争，并从根本上改变它。这个项目将使我们更清楚地认识到这种相互作用，以及如何通过重新评估不可逆转性和波动性的基本概念来利用这种相互作用。有用的发动机产生有限的功率输出。这意味着它们永远不会像理想的无限慢发动机那样高效，因为它们在快速循环中不可避免地浪费能量作为摩擦。功率输出和效率之间的权衡依赖于将这种浪费量化为不可逆的熵产生。我们的工作将以最适合揭示纳米尺度上普遍存在的量子相干性和相关性的新方式重新表述熵产生。除此之外，对于经典机器，已知熵的产生限制了功率输出的时间波动。具体地说，要使发动机在给定的功率输出下发出更少的噼啪声，就必须增加熵的产生。我们将确定这个关系到量子域的高度非平凡的推广。与此同时，我们将开发复杂的数值方法来模拟由许多相互作用的成分组成的复杂量子机器，从而预测这些关键特性。我们的理论框架将对当前旨在工程量子技术的实验工作非常有益。在这个方向上最紧迫的应用将在该项目的范围内进行探索，包括评估增强量子热机的新机制，通过周期性驱动控制量子系统的能力以及实验验证这些发现的建议。该项目的大胆雄心利用了研究团队的协同才能，PI Clark在数值方法方面的专业知识补充了Co-Is Paternostro和Goold的分析技能。