MMQA: MicroKelvin Molecules in a Quantum Array

MMQA：量子阵列中的微开尔文分子

基本信息

批准号：
EP/I012044/1
负责人：
Edward Hinds
金额：
$ 813.01万
依托单位：
Imperial College London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2010
资助国家：
英国
起止时间：
2010 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FI012044%2F1
关键词：
MMQA MicroKelvin Molecules Quantum Array

项目摘要

All matter is governed by quantum physics. Even in bulk material, with huge numbers of particles, many important quantum phenomena persist. When the particles only interact appreciably with their nearest neighbours, it is usually possible to understand the bulk behaviour in terms of the quantum physics of the constituents. Often however, the interactions are long-range and strong, meaning that every particle interacts appreciably with every other particle. The behaviour of the bulk cannot then be understood from that of the constituents, and from a theoretical point of view the system is usually unsolvable. From such strongly interacting quantum systems emerge extraordinary and fascinating phenomena that are not at all well understood, such as high temperature superconductivity and exotic forms of magnetism.Modelling such a complex system on a computer is an impossible task. Instead, we need a physical model of strongly interacting quantum particles where the interactions can be controlled. We plan to build an instrument that cools polar molecules to microKelvin temperatures and below, arranges them in a regular array, and controls their motion, their orientation, and the way they interact. This instrument will be used as a quantum simulator - an ideal, tuneable and highly versatile tool for modelling strongly-interacting quantum systems and understanding the remarkable quantum phenomena they exhibit. This same device could also be used for quantum information processing, or as a multi-particle interferometer for making extremely sensitive measurements of electric, magnetic, gravitational and exotic forces.The use of ultracold polar molecules is crucial for realising this vision. Unlike atoms, the molecules have strong, tuneable, long-range interactions, an essential ingredient for the quantum simulator. While the techniques for cooling atoms to microKelvin temperatures are well established, methods to do the same for molecules are only now emerging. A large part of our programme focuses on developing these methods. We will follow two main routes. One is to start with trapped ultracold atoms, which are then paired up to form weakly-bound ultracold molecules. We will need to transfer them to deeply bound states without heating them up, using a sequence of carefully tailored laser pulses. In the second approach, a beam of molecules from a cryogenic source is decelerated to rest and trapped using electric, magnetic or optical forces. These molecules will be far too hot to form the quantum gas we need, but they could be brought to this regime by sympathetic cooling using ultracold atoms as a refrigerant. The final quantum array will be made by loading our ultracold molecules into a trap formed by laser beams. The configuration of the beams - orientation, polarisation and frequency - allows the quantum evolution to be studied for a wide variety of potentials. Low-frequency external electric fields will be used to control the interactions between molecules.The advances we make will also stimulate new and diverse areas of research: (i) Molecules allows one to test the fundamental symmetries of space and time through measurements of particle dipole moments and the constancy of molecular frequencies. (ii) We will study the collisions of molecules at temperatures where quantum reflection, tunnelling and Bose/Fermi statistics are all important. (iii) Polar molecules can interact with nano-mechanical structures through the long-range dipole interaction, allowing quantum states to be mapped from one to the other. The production of dense samples of ultracold molecules is the key step towards these goals.It will be a major milestone in quantum physics to demonstrate the molecular array. We bring together researchers from Physics and Chemistry at Durham and Imperial, each contributing the highest UK expertise on a key part of our joint programme, to tackle all the experimental and theoretical problems in a unified way.

所有物质都受量子物理学支配。即使在具有大量粒子的散装材料中，许多重要的量子现象仍然存在。当粒子仅与其最近的邻居发生明显相互作用时，通常可以根据成分的量子物理学来理解整体行为。然而，相互作用通常是长程且强烈的，这意味着每个粒子都会与其他粒子发生明显的相互作用。因此，无法从成分的行为来理解整体的行为，并且从理论的角度来看，该系统通常是无法解决的。从这种强相互作用的量子系统中，会出现一些非凡而令人着迷的现象，但这些现象根本无法被很好地理解，例如高温超导性和奇异形式的磁性。在计算机上对这样一个复杂的系统进行建模是一项不可能完成的任务。相反，我们需要一个强相互作用的量子粒子的物理模型，其中相互作用是可以控制的。我们计划建造一种仪器，将极性分子冷却至微开尔文温度及以下，将它们排列成规则的阵列，并控制它们的运动、方向和相互作用的方式。该仪器将用作量子模拟器——一种理想的、可调谐的、高度通用的工具，用于对强相互作用的量子系统进行建模并理解它们所表现出的非凡的量子现象。该设备还可以用于量子信息处理，或者作为多粒子干涉仪，对电、磁、引力和外力进行极其灵敏的测量。超冷极性分子的使用对于实现这一愿景至关重要。与原子不同，分子具有强、可调节、长程的相互作用，这是量子模拟器的重要组成部分。虽然将原子冷却到微开尔文温度的技术已经很成熟，但对分子进行同样处理的方法现在才刚刚出现。我们计划的很大一部分重点是开发这些方法。我们将遵循两条主要路线。一种是从捕获的超冷原子开始，然后将它们配对形成弱结合的超冷分子。我们需要使用一系列精心定制的激光脉冲将它们转移到深度束缚态而不加热它们。在第二种方法中，来自低温源的分子束被减速至静止并利用电力、磁力或光力被捕获。这些分子太热而无法形成我们需要的量子气体，但可以通过使用超冷原子作为制冷剂的交感冷却将它们带到这种状态。最终的量子阵列将通过将我们的超冷分子加载到由激光束形成的陷阱中来制成。光束的配置——方向、偏振和频率——允许研究各种势的量子演化。低频外部电场将用于控制分子之间的相互作用。我们所取得的进步也将刺激新的、多样化的研究领域：（i）分子允许人们通过测量粒子偶极子来测试空间和时间的基本对称性矩和分子频率的恒定性。 (ii) 我们将研究量子反射、隧道效应和玻色/费米统计都很重要的温度下分子的碰撞。（iii）极性分子可以通过长程偶极相互作用与纳米机械结构相互作用，从而允许量子态从一种映射到另一种。超冷分子致密样品的生产是实现这些目标的关键一步。演示分子阵列将是量子物理学的一个重要里程碑。我们汇集了杜伦大学和帝国理工学院的物理和化学研究人员，每个人都在我们联合项目的关键部分贡献了英国最高的专业知识，以统一的方式解决所有实验和理论问题。