Quantum Gravity, Atom Condensate Analogs, and Beyond

这笔赠款将支持引力物理学几个方面的研究项目，从天体物理学到实验室模拟到量子引力。这些项目旨在：1）更多地了解黑洞和中子星周围粒子加速的强大过程所涉及的磁物理学，这有助于解释各种望远镜对这些源的观测; 2）探索中子星可能产生假设的“轴子”场的机制，它是解决核物理理论难题的候选者，并且是“丢失质量”（也称为“丢失质量”）的候选者。3）与实验学家合作，研究超冷原子凝聚体物理学与膨胀宇宙中量子场行为和黑洞霍金辐射之间的密切类比。这项工作可以激发对原子凝聚体性质的新见解，并为纯理论基础理论提供实验室确认和观点; 4）接近调和爱因斯坦的弯曲时空引力理论与量子物理学原理的未解决问题。这些项目类别中的前三个包括与天体物理学，等离子体物理学和原子物理学的重要跨学科联系，这可能会增强不同研究团体和方法之间的协同作用，从而促进科学理解的进步。拟议研究的结果将通过书面文章以及研讨会、会议会谈和座谈会传播。PI将为研究生和本科生提供指导和指导，涉及科学研究，写作和口头交流。PI将在马里兰州大学为9年级学生和对物理感兴趣的高中女生设计和实施暑期课程。所有这些活动都将有助于技术培训和科学素养，以及对物理学见解的理解和欣赏。上述第1）类的具体研究课题包括在广义相对论背景下，以及在存在边界（如中子星星表面或黑洞视界）的情况下，扭曲磁场线的磁螺旋度的尖锐公式，以及回旋运动对停滞表面的影响，停滞表面限定了被引力拉向黑洞或中子星星的电荷与被离心力沿沿着磁场线向外甩出的电荷之间的边界。2）下的研究旨在通过研究中子星外部大量轴子产生的后果来发现观察或约束轴子场的新方法，首先是分析，然后可能是与计算合作者进行数值模拟。这种轴子场与快速射电暴有关的假设也将被探讨。在类别3）中，一个项目将量化凝聚原子数量变化对与霍金辐射相关的相关函数实验室测量的影响。为了解释这些观察结果，这是必要的。另一个项目将分析理论和即将观测到的模式调制（模拟哈勃摩擦）在扩大玻色-爱因斯坦凝聚。这一领域的第三个项目将探索在模拟膨胀宇宙中实验测量声子或磁振子产生的方法。在授标时限内可能会提出意见。最后，4）项研究的一个目标是在时空区域内，利用具有负宇宙学常数的2+1维理论的精确量子化，发展对准定域量子引力的理解，该时空区域是具有固定边界度规的圆盘的因果依赖域。另一个是学习如何在视界附近应用微扰重整化量子引力，以确定当其中一个点接近视界时，引力相互作用是否会抑制两个点的相关函数。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The grant will support research projects on several aspects of gravitational physics, ranging from astrophysical to laboratory analogs to quantum gravity. These projects are aimed at: 1) learning more about the magnetic physics involved in the powerful processes accelerating particles around black holes and neutron stars, which could assist in the interpretation of observations of such sources made with various sorts of telescopes; 2) exploring a mechanism by which neutron stars might source a hypothetical "axion" field, which is a candidate for solving a theoretical puzzle of nuclear physics and is a candidate for the "missing mass" (a.k.a. "dark matter") in the Universe; 3) working with experimentalists to study close analogies between the physics of ultra cold atomic condensates and the behavior of quantum fields in the expanding universe and the Hawking radiation from black holes. This work can stimulate new insights into the properties of atom condensates, and provide laboratory confirmation and perspectives on otherwise purely theoretical fundamental theory; 4) approach the unsolved problem of reconciling Einstein's curved spacetime theory of gravity with the principles of quantum physics. The first three of these project categories include significant interdisciplinary connections to astrophysics, plasma physics, and atomic physics, which may enhance synergy between different research communities and methods, and therefore stimulate progress in scientific understanding. The results of the proposed research will be disseminated through written articles, as well as seminars, conference talks, and colloquia. The PI will provide instruction and mentoring to graduate and undergraduate students, regarding scientific research, writing, and verbal communication. The PI will design and implement instruction in a University of Maryland summer programs for rising 9th graders and for high school girls interested in physics. All of these activities will contribute to technical training and scientific literacy, as well as understanding and appreciation of the insights of physics.Specific research topics in category 1) above include a sharp formulation of magnetic helicity of twisted magnetic field lines in a general relativistic setting, and in the presence of boundaries such as the surface of a neutron star or the horizon of a black hole, and the impact of cyclotron motion on the stagnation surface, which defines the boundary between the charges that are gravitationally pulled to the black hole or neutron star and the charges that are flung outward along magnetic field lines by centrifugal force. Research under 2) aims to discover new ways of observing or constraining an axion field by studying the consequences of copious axion production sourced outside neutron stars, first analytically, and potentially later in numerical simulations with a computational collaborator. The hypothesis that such axion fields are implicated in fast radio bursts will also be explored. In category 3), one project will quantify the effect of variations in the number of condensate atoms on laboratory measurements of the correlation function associated with Hawking radiation. This is necessary in order to interpret those observations. Another project will analyze the theory and upcoming observations of mode modulation (analog Hubble friction) in expanding Bose-Einstein condensates. A third project in this area will explore approaches to experimental measurement of phonon or magnon creation in analog expanding universes. Observations might be possible within the time frame of the award. Finally, one goal of the research under 4) is to develop understanding of quasi-localized quantum gravity, using exact quantization of the 2+1 dimensional theory with a negative cosmological constant, within a spacetime region that is the causal domain of dependence of a disk with a fixed boundary metric. Another is to learn how to apply perturbative renormalized quantum gravity near horizons, to determine whether, as has long been suspected, gravitational interactions quench two point correlation functions when one of the points approaches a horizon.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.