Quantum dynamics of two-body, few-body and many-body molecular systems at low temperatures

低温下二体、少体和多体分子系统的量子动力学

• 批准号: RGPIN-2014-06419
• 负责人: Krems, Roman
• 金额: $ 4.95万
• 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: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=691442
• 关键词: Quantum; dynamics; two; body; few

Funding is requested for a theoretical research program that will explore quantum dynamics of binary, few-body and many-body molecular systems in electromagnetic fields. Specifically, the proposed research will be on three topics: (i) low-temperature dynamics of complex polyatomic molecules and controlled chemistry; (ii) polarons in new interaction regimes; and (iii) controlled energy transfer in open quantum systems. Within each of these topics, we will address the most pressing questions at the forefront of current research in physics and chemistry and only consider molecular systems that have been or can soon be experimentally realized. **The goal of research direction (i) will be to study the feasibility of buffer gas cooling of hydrocarbon molecules to subKelvin temperatures and to develop tools to explore the unique features of bimolecular chemical reactions of cold molecules in electromagnetic fields. This work will be closely related with the experiments on buffer gas cooling of molecules, an emerging research direction aiming to create new technologies for sensitive detection of trace molecules and the production of high-flux beams of polyatomic molecules slowly moving in the laboratory frame. **The research of topics (ii) and (iii) is motivated by the spectacular recent experiments which demonstrated the possibility of synthesizing molecules at temperatures below 1 microKelvin. It was found that ultracold molecules can be very reactive, undergoing chemical reactions at fast rates. It was also demonstrated that ultracold molecules can be trapped in a periodic potential of an optical lattice. Current experiments are focused on improving the trapping fidelity to minimize the effect of disorder, in an effort to produce a periodic, crystal-like system, where molecules are suspended by the laser field potential and intermolecular interactions can be controlled by electromagnetic fields. **We will study the realization of the polaron Hamiltonians with molecules trapped in laser fields. Polarons are quasi-particles appearing in the excitation spectra of particles (such as electrons or excitons) coupled to a bosonic field (such as phonons). We will calculate the phase diagram of polarons in the previously unexplored range of particle - field interaction parameters and study the possibility of observing non-linear polaron interactions in the excitation spectra of cold molecules. We will develop computer codes to study the feasibility of the experimental realization of controlled open quantum systems with molecules trapped in optical lattices. The goal will be to propose an experimental system that could be used to study (a) the dynamics of quantum particles coupled to a finite-size bath near a transition between the Markovian and non-Markovian environment; and (b) control mechanisms of energy transport in open quantum systems with controllable, finite-size baths. **If our results show that complex organic molecules can be cooled to ultracold temperatures, the research field of cold molecules will greatly expand. Within reach will be the possibility to study tunnelling reactions of biological interest without thermal averaging as well as many fundamental phenomena that cannot yet be studied. Examples include effects of the geometric phase and tunable resonances in chemical dynamics, effects of fine structure on chemical transformations and the role of quantum statistics, or lack thereof, in chemical reactivity. Our study of novel polaron problems will connect molecular spectroscopy and condensed-matter physics in new ways, providing a new stimulus to both research fields. The realization of controllable open systems with trapped molecules may become a new paradigm in the study of few-particle dynamics under dissipation.

要求提供一项理论研究计划，该计划将探索电磁场中二元，几体和多体分子系统的量子动力学。具体而言，拟议的研究将在三个主题上：（i）复杂多原子分子和受控化学的低温动力学； （ii）新互动制度的极性； （iii）开放量子系统中的控制能量转移。 在这些主题中的每个主题中，我们将在当前的物理学和化学研究中解决最紧迫的问题，并且仅考虑已经或可以很快就可以实验实现的分子系统。 **研究方向（i）的目的是研究烃分子对subkelvin温度的缓冲气体冷却的可行性，并开发工具以探索电磁场中冷分子的双重分子化学反应的独特特征。这项工作将与分子缓冲气体冷却的实验密切相关，这是一个新兴的研究方向，旨在创建新技术，以敏感地检测微量分子，并在实验室框架中缓慢移动多原子分子的高升光束。 **主题（II）和（III）的研究是由壮观的最近实验激发的，这些实验表明在低于1微毛素的温度下合成分子的可能性。 发现超冷分子可以非常反应性，以快速速率进行化学反应。还证明，超冷分子可以被困在光学晶格的周期性电位中。当前的实验集中在改善诱捕保真度以最大程度地减少疾病的影响，以产生一个周期性的晶体样系统，在这种系统中，可以通过激光场电位悬浮分子，并且可以通过电磁场控制分子间相互作用。 **我们将研究用被困在激光场中的分子的北极子哈密顿量的实现。极性子是出现在粒子（例如电子或激子）的激发光谱中的准粒子，该粒子与骨磁场（例如声子）耦合在一起。我们将在先前未开发的粒子 - 场相互作用参数范围内计算极化子的相图，并研究观察冷分子激发光谱中非线性极性相互作用的可能性。我们将开发计算机代码，以研究被捕获在光学晶格中的分子的受控开放量子系统实现实验性的可行性。目的是提出一个实验系统，该系统可用于研究（a）在马尔可夫和非马克维亚环境之间过渡的过渡时，偶联的量子颗粒的动力学； （b）具有可控制的有限大小浴缸的开放量子系统中能量传输的控制机制。 **如果我们的结果表明，复杂的有机分子可以冷却至超低温度，那么冷分子的研究领域将大大扩展。触手可及的可能性是研究生物学兴趣的隧道反应，而无需热平均以及许多尚未研究的基本现象。例子包括几何阶段和可调节谐振在化学动力学中的影响，精细结构对化学转化的影响以及量子统计的作用或缺乏化学统计的作用。我们对新型二极管问题的研究将以新的方式连接分子光谱和凝结物理物理学，从而为这两个研究领域提供新的刺激。在耗散下的几个粒子动力学研究中，具有捕获分子的可控开放系统的实现可能成为一种新的范式。