Control and study of molecular dynamics in many-body quantum systems

多体量子系统中分子动力学的控制与研究

• 批准号: RGPIN-2019-04210
• 负责人: Milner, Valery
• 金额: $ 3.64万
• 依托单位: University of British Columbia
• 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=763050
• 关键词: Control; study; molecular; dynamics; many

My research is focused on controlling molecular dynamics with laser pulses, whose intensity, phase and polarization are tailored so as to make the molecule rotate in a desired way. In recent years, my group has developed methods of controlling molecular rotation with such laser instruments as an "optical centrifuge" and a "chiral pulse train". We have since used them to study new and exotic molecular objects, known as "molecular super-rotors". Super-rotors are ultrafast rotating molecules whose synchronous uni-directional rotation is controlled by the laser field. Our centrifuge is one of three in the world (two until 2017) and the only one in Canada. It is also the only centrifuge worldwide in which the three fundamental parameters of molecular "super-rotation" - its frequency, directionality and phase - can be measured directly. This unique tool enabled us to perform a number of pioneering molecular studies, impossible in any other research laboratory. Until now, we have investigated the properties of isolated molecular super-rotors and their collisional properties within thermal molecular ensembles, where quantum correlations and many-body physics are of little importance. In the next few years, I will expand this research to studying rotational dynamics of molecules embedded in quantum media. We will investigate coherent molecular rotation inside three types of quantum environment: (1) the macroscopic bath of superfluid liquid helium; (2) its small nanoscale realization in the form of a helium nanodroplet containing a few thousand helium atoms; and (3) an even smaller cluster of up to a few tens of helium atoms. Molecular rotors, whose spatial orientation and coherent rotational dynamics will be accurately controlled with our shaped laser pulses, will be used as local nano-probes of these correlated quantum media. We will study the appearance and the manifestation of superfluidity at different length scales by monitoring and characterizing the rotation of an embedded molecule, as well as the response of the medium to that rotation. Owing to the unique properties of isolated molecular super-rotors, found in our recent works, I anticipate many interesting discoveries from bringing these exotic molecular objects in direct contact with many-body quantum systems, e.g. a superfluid. Understanding complex quantum media, in which the motion of an individual molecule becomes entangled with the dynamics of the surrounding atoms and molecules through a collective many-body quantum state, is key to the progress in emerging quantum technologies, which are expected to revolutionize secure communications, computer analysis of biological systems, and sensing of small changes in electrical, magnetic and gravitational fields. An exposure to the state-of-the-art laser technology, such as an optical centrifuge, ensures that my students will have an unmatched training opportunity which will prepare them for careers either in academic or industrial sector.

我的研究主要集中在用激光脉冲控制分子动力学，其强度，相位和偏振被定制，以便使分子以期望的方式旋转。近年来，我的研究小组已经开发出用诸如“光学离心机”和“手征脉冲序列”等激光仪器控制分子旋转的方法。从那时起，我们就用它们来研究新的和奇异的分子物体，称为“分子超级转子”。超转子是超高速旋转的分子，其同步单向旋转由激光场控制。我们的离心机是世界上三台离心机之一（两台直到2017年），也是加拿大唯一的离心机。它也是世界上唯一一台可以直接测量分子“超旋转”的三个基本参数--频率、方向性和相位的离心机。这种独特的工具使我们能够进行许多开创性的分子研究，这在任何其他研究实验室都是不可能的。 到目前为止，我们已经研究了孤立分子超转子的性质和它们在热分子系综中的碰撞性质，其中量子关联和多体物理并不重要。在接下来的几年里，我将把这项研究扩展到研究嵌入量子介质中的分子的旋转动力学。我们将研究三种类型的量子环境中的相干分子旋转：（1）超流液氦的宏观浴;（2）它的小纳米尺度实现，即含有几千个氦原子的氦纳米滴;（3）甚至更小的几十个氦原子的簇。分子转子，其空间取向和相干旋转动力学将被精确控制与我们的形状的激光脉冲，将被用作这些相关的量子介质的本地纳米探针。我们将通过监测和表征嵌入分子的旋转以及介质对旋转的响应来研究不同长度尺度下超流性的外观和表现。 由于在我们最近的工作中发现的孤立分子超转子的独特性质，我预计将这些奇异的分子物体与多体量子系统（例如超流体）直接接触会有许多有趣的发现。理解复杂的量子介质，其中单个分子的运动通过集体多体量子态与周围原子和分子的动力学纠缠在一起，是新兴量子技术进步的关键，这些技术有望彻底改变安全通信、计算机分析生物系统以及对电、磁和重力场微小变化的传感。接触最先进的激光技术，如光学离心机，确保我的学生将有一个无与伦比的培训机会，这将为他们在学术或工业部门的职业生涯做好准备。