CAREER: Illuminating the Early Universe with Dark Matter

该职业奖资助查佩尔山的北卡罗来纳州大学的Adrienne Erickcek教授的研究活动。 对宇宙中最古老的光的观测表明，在大爆炸后不久，宇宙中有一段加速膨胀的时期，称为暴胀。 在暴胀期间，宇宙能量密度的量子涨落在宇宙学尺度上留下了印记，为最终成为星系的结构播下了种子。 我们不知道通货膨胀为什么会发生，也不知道它为什么会结束。 此外，暴胀使宇宙中没有任何物质和辐射，但测量到的轻元素丰度意味着宇宙在暴胀结束后一秒钟充满了极热的辐射。 Erickcek教授的目标是通过研究最小的引力束缚暗物质团块来填补宇宙学记录中的这一空白，暗物质是一种未知的质量来源，目前占宇宙能量密度的25%左右。 除了提高我们对早期宇宙和暗物质性质的理解--从而通过促进科学进步来促进国家利益--这个项目还将产生更广泛的影响。 研究生和本科生将有助于这项调查，并将接受培训，在物理宇宙学和广泛适用的数学和计算技术。 Erickcek教授还将通过与Morehead天文馆和科学中心的教育工作者合作，为高中学生带来这项研究的兴奋，开发一个基于探究的课程模块，将暗物质的证据纳入牛顿力学的课程中，从而使学生接触到宇宙学的一个伟大奥秘。 该模块将公开提供，Erickcek教授将在北卡罗来纳州教学会议上领导专业发展讲习班，培训高中教师在课堂上使用该模块。 最后，Erickcek教授将通过主办Morehead的卡罗莱纳科学咖啡馆和青少年科学咖啡馆与公众分享她的研究。更具体地说，最小最早的暗物质晕的形成为我们提供了一个了解暴胀和热大爆炸之间的差距的窗口，因为它们的丰度受到暴胀最后阶段产生的密度波动的性质以及宇宙在暴胀过程中的演化的影响。第一秒。 Erickcek教授将把她以前的工作扩展到伽马射线观测如何在早期物质主导的时代限制热暗物质的产生，以其他热历史和暗物质产生机制。 这项研究将缩小潜在的暗物质候选者的领域，通过限制他们的生产机制，并打破遗迹丰度和热历史之间的简并。 特别是，它将确定质量在TeV尺度左右的引力耦合模场是否与中性伴子暗物质相容，并可能排除超重隐藏扇区粒子作为暗物质候选者。 这项调查还将确定如何增强小尺度的不均匀性膨胀过程中产生的影响微晕丰度和暗物质湮灭率。 Erickcek教授的小组将推导出对小尺度原始波动的强约束，这将提高我们对暴胀的理解。 这两项任务都将利用微晕形成的小盒子、高红移模拟。 最后，Erickcek教授将探讨如何观测宇宙微波背景，21厘米层析成像，对星系际介质温度的测量可能会揭示早期-该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的评估来支持。影响审查标准。

This CAREER award funds the research activities of Professor Adrienne Erickcek at the University of North Carolina at Chapel Hill. Observations of the oldest light in the Universe indicate that there was a period of accelerated expansion, called inflation, shortly after the Big Bang. During inflation, quantum fluctuations in the energy density of the Universe were imprinted on cosmological scales, seeding the structures that eventually became galaxies. We do not know why inflation happened or why it ended. Moreover, inflation left the Universe devoid of all matter and radiation, yet the measured abundances of light elements imply that the Universe was filled with extremely hot radiation one second after inflation ended. Professor Erickcek aims to fill this gap in the cosmological record by studying the smallest gravitationally bound clumps of dark matter, which is an unknown source of mass that currently makes up about 25% of the energy density of the Universe. In addition to improving our understanding of the early Universe and the properties of dark matter --- thus advancing the national interest by promoting the progress of science --- this project will also have significant broader impacts. Graduate and undergraduate students will contribute to this investigation and will receive training both in physical cosmology and in widely applicable mathematical and computational techniques. Professor Erickcek will also bring the excitement of this research to high-school students by working with educators at the Morehead Planetarium and Science Center to develop an inquiry-based curriculum module that incorporates the evidence for dark matter into lessons on Newtonian mechanics, thereby exposing students to one of the great mysteries of cosmology. This module will be made publicly available, and Professor Erickcek will lead professional-development workshops at North Carolina teaching conferences to train high-school teachers to use this module in their classrooms. Finally, Professor Erickcek will share her research with the general public by hosting Morehead's Carolina Science Cafe and Teen Science Cafe.More specifically, the smallest and earliest-forming dark matter halos provide a window into the gap between inflation and the hot Big Bang because their abundance is affected by the properties of the density fluctuations created during the final stages of inflation and the evolution of the Universe during its first second. Professor Erickcek will extend her prior work on how gamma-ray observations constrain thermal dark-matter production during an early matter-dominated era to other thermal histories and dark-matter creation mechanisms. This investigation will narrow the field of potential dark-matter candidates by restricting their production mechanisms and breaking the degeneracy between relic abundance and thermal history. In particular, it will determine if gravitationally coupled moduli fields with masses around the TeV scale are compatible with neutralino dark matter, and may rule out super-heavy hidden-sector particles as dark-matter candidates. This investigation will also determine how enhanced small-scale inhomogeneity generated during inflation affects the microhalo abundance and the dark-matter annihilation rate. Professor Erickcek's group will then derive robust constraints on small-scale primordial fluctuations that will improve our understanding of inflation. Both of these tasks will utilize small-box, high-redshift simulations of microhalo formation. Finally, Professor Erickcek will explore how observations of the cosmic microwave background, 21cm tomography, and measurements of the temperature of the intergalactic medium may expose the existence of early-forming microhalos and allow us to close this gap in our understanding of the early Universe.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.