Quantum Field Theory and Cosmology

观测宇宙学提供了第一个关于量子引力的数据，这催化了这门学科从推测到硬科学的艰难历程。相反，量子引力有可能帮助解决宇宙学面临的一些重大难题，包括：(a)是什么导致了宇宙诞生时最初的膨胀，如何对其进行测试？(b)爱因斯坦引力理论的修正是否可以免除对当前能量密度（占总数的95% !）的巨大未被探测到的和外来的贡献，这些贡献需要解释星系、星系团和宇宙的整体膨胀？本项目探讨了解决这些问题的新方法。它还将促进教学、培训和学习。PI在教学方面的成功得到了他所在机构和美国物理学会的认可。超过一半的PI现在和过去的研究生属于代表性不足的群体，其中包括两名在美国担任重要STEM教育职位的人。PI在外联方面也非常活跃，发表了被高度引用的评论文章和许多流行的讨论会。​(2)暴胀的量子反反应——将函数依赖扩展到标准模型场，研究它们与暴胀的耦合如何改变暴胀，并利用非局部可观测物的重整化的最新进展，研究暴胀引力子如何改变暴胀。(3)非局部引力模型——研究PI的非局部修正引力模型中的结构形成，该模型省去了暗物质，并解决了PI的非局部宇宙学模型如何比广义相对论更好地描述结构形成的悖论。(4)量子环效应——利用最近的进展，在引力子如何改变粒子运动学和远程力的计算中消除规范依赖。该奖项反映了美国国家科学基金会的法定使命，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。

Observational cosmology has provided the first-ever data on quantum gravity, and this is catalyzing the difficult passage of the subject from speculation to hard science. Conversely, quantum gravity has the potential to help resolve some of the great puzzles which confront cosmology, including: (a) What caused the initial spurt of expansion at the birth of the universe and how can it be tested? (b) Can modifications of Einstein's gravity theory dispense with the huge undetected and exotic contributions to the current energy density (95% of the total!) needed to account for galaxies, galaxy clusters and for the overall expansion of the universe? This project examines novel solutions to these questions. It will additionally promote teaching, training and learning. The PI's success in teaching has been recognized by awards at his own institution and by the American Physical Society. More than half the PI's current and past graduate students belong to under-represented groups, including two who are filling vital STEM educational positions within the United States. The PI has also been very active in outreach, with highly-cited review articles and numerous popular colloquia.The PI's group will continue their collaborations with Prof. Shun-Pei Miao (NCKU, Taiwan), Prof. Tomislav Prokopec (U. Utrecht, Netherlands) and Prof. Nikolaos Tsamis (U. Crete, Greece) to pursue analytical and numerical research in four areas: (1) Phenomenology of perturbations --- exploit the newly-derived functional dependence to reconstruct the geometry from data and to design new statistics which maximize non-Gaussianity from features in the power spectrum. (2) Quantum back-reaction on inflation --- extend the functional dependence to Standard Model fields to study how their couplings to the inflaton would modify inflation, and exploit recent progress in renormalizing nonlocal observables to study how inflationary gravitons modify inflation. (3) Nonlocal models of gravity --- study structure formation in the PI's nonlocal modified gravity model which dispenses with dark matter, and resolve a paradox in how the PI's nonlocal cosmology model contrives to describe structure formation better than general relativity. (4) Quantum loop effects --- exploit recent progress in removing the gauge dependence in calculations of how gravitons modify particle kinematics and long range forces.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.