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

全尺寸量子计算机将需要在持续相干的受保护状态下的大量量子比特。这是一个挑战。宏观尺度的孤立量子系统通常符合本征态热化假说。在这里，量子统计力学适用，本征态叠加只是在由能量密度定义的温度下遍历演化。但是，在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、保持空间秩序和在状态叠加中局域化能量的条件。一些探索超冷原子动力学的高度工程化的实验证实了光学晶格中的多体定域化(MBL)原理。在新的研究中，我们改变了范式，提供了一条通向具有MBL所有特征的状态的直接途径。我们研究了里德堡气体，在这种气体中，电子碰撞雪崩电离和定形流体动力膨胀使系统熄灭，形成超冷中性等离子体。在这里，运动的局部积分(LOM)控制着强烈无序地貌中粒子和能量密度的传播。这些Liom创造了局部涌现的守恒定律，指导着全球多体定域态的自发形成。像由超冷原子组成的基于晶格的量子多体系统一样，淬灭的超冷等离子体的局域态提供了作为模拟量子模拟器的前景，或者是嵌入离散原子或分子量子比特的受保护的区域。新的工作将建立在我们对这些量子动力学的初步观察的基础上。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定域动力学。我们将使用毫米波辐射的高分辨率数字合成器来探测定域(泊松)和离域(Wigner-Dyson)能级间距统计。雪崩和猝灭的机制造成了粒子距离的狭窄分布。这可能会在受阻弛豫的量子动力学中发挥作用。我们建议用可见光相干衍射成像的方法来研究NO和其他分子的等离子体，以发展空间相关性。干涉成像还将出现在Discovery Grant的一个平行项目中，该项目研究通过高分辨率干涉背向散射(ISCAT)-拉曼显微镜对复杂材料进行亚微米分析和分类。我们将开发多变量分析策略，实时确定纳米颗粒的尺寸分布，并探索本地样品的三维结构。我们通过衍射限制焦点的声光偏转来照射大范围的视场。这幅图像的频率分辨率提供了宽达100 x 100微米的共焦拉曼图谱。“我们将在积极的本地和国际合作的背景下，建立这些独特的仪器能力。

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.