Laser Spectroscopy of Isolated Molecules and Complex Systems: Structure, Dynamics and Analysis

全尺寸的量子计算机将需要大量的量子比特，这些量子比特处于持续相干的受保护状态。这是一个挑战。宏观大小的孤立量子系统通常符合本征态热化假说。在这里，应用量子统计力学，特征态叠加只是在由能量密度定义的温度下进行遍历演化。但是，在一个对量子材料领域具有重要意义的发展中，理论发现了无序量子多体系统避免退相干、保持空间秩序和将能量定域于态叠加的条件。研究超冷原子动力学的少数精心设计的实验证实了光学晶格中的多体定位（MBL）原理。在新的研究中，我们改变了范式，提供了一条通往具有MBL所有特征的状态的直接途径。我们研究了里德堡气体中电子冲击雪崩电离后的形状流体动力膨胀使系统淬火形成超冷中性等离子体。在这里，局部运动积分（LIOM）控制着粒子和能量密度在强无序景观中的传播。这些LIOM创造了局部涌现的守恒定律，指导全局多体局域状态的自发形成。就像由超冷原子组成的基于晶格的量子多体系统一样，淬火超冷等离子体的局域状态为模拟量子模拟器或嵌入离散原子或分子量子比特的保护机制提供了希望。新的工作将建立在我们对这些量子动力学的初步观察之上。我们将进一步研究一氧化氮和其他超冷等离子体的猝灭和局部化动力学。我们将使用高分辨率的毫米波辐射数字合成器来探测局域化（泊松）和非局域化（维格纳-戴森）电平间隔统计。雪崩和淬灭的机制造成了粒子距离的狭窄分布。这可能在量子动力学中发挥作用。我们提出利用可见光相干衍射成像技术研究NO和其他分子的等离子体以发展空间相关性。干涉成像也将在探索基金的平行项目中使用高分辨率干涉后向散射(iSCAT) -拉曼显微镜对复杂材料进行亚微米分析和分类。我们将开发多元分析策略，实时确定纳米颗粒的大小分布，并探测原生样品的三维结构。我们通过衍射限制焦点的声光偏转来照亮宽视场。该图像的频率分辨率可提供宽为100 x 100微米的共聚焦拉曼图。我们将在积极的地方和国际合作的背景下，利用这些独特的工具能力。

Full-scale quantum computers will require large ensembles of qubits in protected states of sustained coherence. This presents a challenge. Isolated quantum systems of macroscopic size normally conform with the Eigenstate Thermalization Hypothesis. Here, quantum statistical mechanics applies, and eigenstate superpositions just evolve ergodically at a temperature defined by the energy density.   But, in a development with great significance for the field of quantum materials, theory has found conditions under which disordered quantum many-body systems avoid decoherence, preserve spatial order and localize energy in superpositions of states. A small number of highly engineered experiments probing the dynamics of ultracold atoms confirm the principle of many-body localization (MBL) in optical lattices. In new research, we have changed the paradigm, offering a straightforward route to a state with all the hallmarks of MBL. We study Rydberg gases in which electron-impact avalanche ionization followed by shaped hydrodynamic expansion quenches the system to form an ultracold neutral plasma. Here, local integrals of motion (LIOM) govern the propagation of particle and energy density in a strongly disordered landscape. These LIOM create locally emergent conservation laws that guide the spontaneous formation of a global many-body localized state. Like lattice-based quantum many-body systems composed of ultracold atoms, the localized state of a quenched ultracold plasma offers promise as an analog quantum simulator, or a protected regime in which to embed discrete atomic or molecular qubits.   New work will build on our preliminary observations of these quantum dynamics. We will further investigate the quenching and localization dynamics of nitric oxide and other ultracold plasmas. We will use a high-resolution digital synthesizer of mm-wave radiation to probe for localized (Poisson) versus delocalized (Wigner-Dyson) level-spacing statistics. The mechanics of avalanche and quench create a narrow distribution of particle distances.  This may play a role in the quantum dynamics of arrested relaxation. We propose to study plasmas of NO and other molecules for the development of spatial correlation by means of coherent diffractive imaging with visible light.   Interferometric imaging will also figure in a parallel program of Discovery Grant research on the sub-micron analysis and classification of complex materials by high-resolution interferometric backscattering (iSCAT) - Raman microscopy.  We will develop multivariate analysis strategies that determine nanoparticle size distributions in real time, and probe three-dimensional structure in native samples. We illuminate a wide field by the acousto-optical deflection of a diffraction-limited focus. Frequency resolving this image affords a confocal Raman map as wide as 100 x 100 µm.  We will build on these unique instrumental capabilities in a context of active local and international collaborations.