Quantum Optics with Ultra-Narrow Gamma Resonances

共振是指物质对系统特征频率(“共振频率”)附近的一个窄频率范围(称为“共振宽度”)的周期性(振荡)力的强烈响应，是一种普遍存在的普遍物理现象。不同类型的共振，如电子、等离子体、原子和分子共振，在很大的频率范围内(从无线电频率到红外、光学和紫外线)发生，并发现了许多应用。例如，它们被用来接收特定的无线电台，产生激光辐射，检测微量的特定化合物，并保持时钟以相同的速度滴答作响。利用超冷原子内部的电子，共振品质因数(定义为共振频率与共振宽度之比)已经达到了高达10的17次方(1后面跟着17个零)。通过使用原子核而不是电子，由这笔拨款资助的研究人员正试图达到更高质量因数的数量级(例如10的19次方)。这些共振是在x射线/伽马射线频率上，而不是在对应于可见光的频率上。使用原子核不需要对原子进行深度冷却，也不限于少量稀释的原子集合--它可以在室温下在块状(固体)物质中完成。然而，由于缺乏产生相对明亮、光谱较窄的X射线/伽马射线辐射并控制其与原子核相互作用的技术，他们的研究具有挑战性。该项目旨在开发此类技术，并对超窄核伽马射线共振进行演示、探索和应用。它的成功实现将有力地推动量子核计量和技术的发展，从核钟到超分辨率核谱仪，从光谱增强型准单色X射线源到紧凑型长寿命核量子存储器，在基础物理、量子信息科学、化学、生物、医学和材料纳米科学的高精度测试中具有潜在的应用前景。研究生和本科生将通过学习实验技术、分析方法和数值建模，在这个新兴的高度跨学科的研究领域接受量子光学和X射线光学之间的边界方面的培训。该项目由两部分组成。第一个目标是开发通过X射线辐射与核靶的共振相互作用对其光谱含量和时间形状进行相干控制的技术。它包括：1)单光子以~30m/S的有效速度在物质中传播的慢速；2)双色伽马光子的透明度；3)量子核存储；4)伽马光子的光谱强度增强。实验将基于最近支持的课题组的理论建议和实验成果(X.Zhang等人)。太棒了。莱特牧师。123,250504(2019年)；Y.V.Radeonchev等人。太棒了。莱特牧师。163602(2020年))，并在德克萨斯农工大学的研究实验室使用14.4keV的铁-57原子核跃迁和1.1兆赫兹的辐射线展宽进行了实验，该辐射线由钴-57的放射源激发。该项目的第二部分旨在演示用于Sscum-45核跃迁的12.4keV超窄(0.17赫兹)共振。这些实验将在欧洲XFEL进行，这是目前10-25keV光子范围内最亮的硬X射线辐射源，而所需单色器和分束器的制造和初步测试将由Argonne国家实验室的共同PI小组完成。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Resonance, the strong response of matter to a periodic (oscillating) force in a narrow frequency range (called the "resonance width") in the vicinity of the characteristic frequency of the system (the "resonant frequency"), is a widespread general physical phenomenon. Different types of resonances such as electronic, plasmonic, atomic, and molecular resonances, occur in a wide range of frequencies (from radio frequency to infrared, optical, and ultra-violet), and find numerous applications. For example, they are used to pick up a particular radio station, to generate laser radiation, to detect trace amounts of specific chemical compounds, and to keep a clock ticking at the same rate. Resonance quality factors (defined as the ratio of the resonant frequency to the resonance width) have been achieved as high as 10 to the 17th power (1 followed by 17 zeros) using the electrons inside ultra-cold atoms. By using the atomic nucleus rather than the electrons, researchers funded by this grant are attempting to reach orders of magnitude higher quality factors (such as 10 to the 19th power). These resonances are at x-ray/gamma-ray frequencies rather than at the frequencies corresponding to visible light. Using the nucleus does not require a deep cooling of the atom, and is not limited to small diluted collections of atoms--it can be done in bulk (solid) matter at room temperature. However their investigation is challenging due to the absence of the techniques to produce relatively bright spectrally narrow x-ray/gamma-ray radiation and to control its interaction with the nucleus. This project aims at the development of such techniques and at the demonstration, exploration and applications of the ultra-narrow nuclear gamma-ray resonances. Its successful realization would give strong impetus to the development of quantum nuclear metrologies and technologies, from nuclear clocks to super-resolution nuclear spectrometers, from spectrally enhanced quasi-monochromatic x-ray sources to compact long-lived nuclear quantum memories with potential applications in high-precision tests of fundamental physics, quantum information science, chemistry, biology, medicine, and material nanoscience. The graduate and undergraduate students will be trained in this emerging highly interdisciplinary research field on the borderlines between quantum and x-ray optics by learning the experimental techniques, analytical methods, and numerical modeling. The project consists of two parts. The first one aims at the development of the techniques for coherent control of the spectral content and temporal shape of x-ray radiation via its resonant interaction with nuclear targets. It includes the demonstration of i) slow single gamma-photons propagating through matter with an effective speed of ~30m/s, ii) transparency for the bichromatic gamma-ray photons, iii) quantum nuclear memories, and iv) spectral intensity enhancement of gamma-ray photons. The experiments will be based on the recent theoretical proposals and experimental achievements of the supported research group (X. Zhang et al. Phys. Rev. Lett. 123, 250504 (2019); Y. V. Radeonychev, et al. Phys. Rev. Lett. 124, 163602 (2020)) and performed in the researchers lab at Texas A&M University using a 14.4 keV transition of Iron-57 nuclei with 1.1 MHz radiative line broadening excited with the heralded radioactive source of Cobalt-57. The second part of the project aims at demonstrating the ultra-narrow (0.17Hz) resonance at 12.4 keV for a nuclear transition in Scandium-45. These experiments will be performed at the European XFEL, currently the brightest source of hard x-ray radiation in the range of 10-25 keV photons, while the fabrication and preliminary testing of the required monochromators and beam splitters will be done by the co-PI’s group at the Argonne National Laboratiory.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.