Simulating ultracold quantum chemistry at conical intersections

模拟圆锥形交叉点的超冷量子化学

• 批准号: EP/W015641/1
• 负责人: Weibin Li
• 金额: $ 51.08万
• 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: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FW015641%2F1
• 关键词: Simulating; ultracold; quantum; chemistry; conical

Computing the electronic structure and dynamics of molecules is a central challenge in the field of modern quantum chemistry. As the computational cost grows exponentially with the size of the molecule, solving the electronic structure problems in a classical computer becomes a formidable task. However, nowadays quantum computation and simulation become increasingly available to understand and characterise intricate many-body quantum states and the dynamics of molecules. Using quantum computers developed at, e.g., IBM and Google, electronic structures in low-lying states have been successfully determined. Nevertheless, challenging tasks remain, with one being the investigation of electronic dynamics when two close-lying electronic potential energy surfaces cross in high dimensional coordinate space. Such exceptional point forms a conical intersection, where intriguing chemical processes governed by topological effects and non-adiabatic transitions occur. Conical intersections also play critical roles in many photochemical and photobiological reactions, such as vision and stability of DNA. However, directly observing the resulting non-adiabatic dynamics is difficult, as it takes place on a femtosecond time scale and on length scales of a few Angstroms. As a result, any measurement will excite a vast number of vibrational states of the molecule, which inevitably leads to heating. This not only prevents the observation of quantum and topological effects, but also causes obstacles in interpreting the experiment theoretically. Furthermore, commonly used approaches, such as the Born-Oppenheimer approximation, fail near conical intersections. In order to address this challenge, we will conduct a research programme that introduces an analogue quantum simulation platform - consisting of a pair of interacting trapped Rydberg ions - to engineer conical intersections and to investigate their ensuing dynamics at length and time scales of the order of nanometres and microseconds, respectively. In an ion trap, the vibrational states of the ions can be laser cooled to nearly zero temperature, allowing the study of fully coherent processes in the vicinity of a conical intersection. This paves a new route towards simulating and probing ultracold quantum chemistry in real time via direct spectroscopic measurements in state-of-the-art trapped ion setup. Building on our initial work, the aim of this proposal is also to uncover novel many-body non-equilibrium and topological phenomena which are enabled by conical intersections but have no immediate counterpart in molecules. This will be enabled by the unprecedented level of controllability over the dimension, size, electron-vibration couplings offered by the Rydberg ion quantum simulator. The expected outputs will be of high relevance not only for the related academic community, but also for the ongoing development of quantum technologies. We will establish a comprehensive theoretical framework for simulating quantum chemistry with trapped Rydberg ions, and by working closely with the internationally pioneering experimental group, we will design protocols to probe coherent dynamics and effects. Our interdisciplinary research will create connections between the UK and the international trapped ion and Rydberg physics communities and thereby strengthen the UK's world-leading position in the area of quantum simulation and quantum computation.

计算分子的电子结构和动力学是现代量子化学领域的核心挑战。由于计算成本随着分子大小呈指数级增长，在经典计算机中解决电子结构问题成为一项艰巨的任务。然而，如今量子计算和模拟变得越来越可用于理解和表征复杂的多体量子态和分子动力学。使用IBM和谷歌等公司开发的量子计算机，已经成功确定了低洼态的电子结构。然而，具有挑战性的任务仍然存在，其中之一是研究两个紧密相连的电子势能表面在高维坐标空间中交叉时的电子动力学。这样的特殊点形成了一个圆锥形交叉点，其中发生了由拓扑效应和非绝热转变控制的有趣的化学过程。圆锥形交叉点在许多光化学和光生物学反应中也发挥着关键作用，例如视觉和 DNA 的稳定性。然而，直接观察由此产生的非绝热动力学很困难，因为它发生在飞秒时间尺度和几埃的长度尺度上。因此，任何测量都会激发分子的大量振动状态，这不可避免地导致加热。这不仅阻碍了量子效应和拓扑效应的观察，而且给实验的理论上解释带来了障碍。此外，常用的方法（例如玻恩-奥本海默近似）在圆锥形交叉点附近会失败。为了应对这一挑战，我们将开展一项研究计划，引入一个模拟量子模拟平台（由一对相互作用的俘获里德伯离子组成）来设计圆锥形交叉点，并研究其在长度和时间尺度上的后续动态。分别为纳米和微秒。在离子阱中，离子的振动状态可以被激光冷却到接近零的温度，从而可以研究圆锥形交叉点附近的完全相干过程。这为通过最先进的捕获离子装置中的直接光谱测量来实时模拟和探测超冷量子化学铺平了一条新途径。在我们最初的工作的基础上，该提案的目的还在于揭示新颖的多体非平衡和拓扑现象，这些现象是由圆锥形相交实现的，但在分子中没有直接对应物。这将通过里德堡离子量子模拟器提供的对尺寸、尺寸、电子振动耦合的前所未有的可控性水平来实现。预期成果不仅对于相关学术界，而且对于量子技术的持续发展也具有高度相关性。我们将建立一个全面的理论框架，用于模拟捕获里德伯离子的量子化学，并通过与国际领先的实验组密切合作，设计协议来探测相干动力学和效应。我们的跨学科研究将在英国与国际俘获离子和里德堡物理界之间建立联系，从而加强英国在量子模拟和量子计算领域的世界领先地位。

项目成果

High-Sensitivity Rydberg-Atom-Based Phase-Modulation Receiver for Frequency-Division-Multiplexing Communication

• DOI: 10.1103/physrevapplied.19.044079
• 发表时间: 2023-04
• 期刊: Physical Review Applied
• 影响因子: 4.6
• 作者: Y. Cai;Shuai Shi;Yijia Zhou;Yitong Li;J. Yu;Weibin Li;Lin Li

High-fidelity interconversion between Greenberger-Horne-Zeilinger and $W$ states through Floquet-Lindblad engineering in Rydberg atom arrays

通过里德堡原子阵列中的 Floquet-Lindblad 工程实现 Greenberger-Horne-Zeilinger 和 $W$ 态之间的高保真相互转换

• DOI: 10.48550/arxiv.2303.13039
• 发表时间: 2023
• 作者: Shao X

Accessing and manipulating dispersive shock waves in a nonlinear and nonlocal Rydberg medium

• DOI: 10.1103/physreva.107.033503
• 发表时间: 2022-10
• 期刊: Physical Review A
• 影响因子: 2.9
• 作者: C. Hang;Zhengyang Bai;Weibin Li;A. Kamchatnov;Guoxiang Huang

Rydberg-ion flywheel for quantum work storage

• DOI: 10.1103/physreva.108.l050201
• 发表时间: 2023-04
• 期刊: Physical Review A
• 影响因子: 2.9
• 作者: W. S. Martins;F. Carollo;Weibin Li;K. Brandner;I. Lesanovsky

Facilitation Induced Transparency and Single Photon Switch with Dual-Channel Rydberg Interactions

具有双通道里德伯相互作用的促进诱导透明度和单光子开关

• DOI: 10.48550/arxiv.2205.14621
• 发表时间: 2022
• 作者: Ding Y