Next generation data analysis for CMB and large-scale structure

宇宙学是从大爆炸到现在，在最大尺度上研究宇宙。总体目标是回答科学中一些最古老的问题：宇宙是由什么组成的？它是如何开始的？它将如何结束？我们对这些问题的探索带来了深刻的惊喜。我们已经知道，宇宙中只有一小部分是由我们在地球上熟悉的普通原子物质组成的。宇宙的大部分是由“暗物质”构成的，这是一种我们无法在实验室中制造或观察到的物质。我们有候选理论来解释宇宙是如何开始的，或者更准确地说，宇宙是如何进入大爆炸状态的：热的、稠密的、几乎均匀的。这些理论需要一个或多个新的领域——从未在实验室中观察到的领域——通过量子力学过程产生大爆炸状态。最后，我们发现，在最近的宇宙历史中，宇宙已经开始被“暗能量”所主导，这是一种类似流体的能量和压力源，与暗物质和普通物质不同。

Cosmology is the study of the universe on its largest scales, from the Big Bang until now. The overarching goal is to answer some of the oldest questions in science: What is the universe made of? How did it begin? How will it end? Our quest to answer these questions has led to profound surprises. We have learned that only a small fraction of the universe is composed of the ordinary atomic matter we are familiar with on Earth. Most of the universe is made of "dark matter", a type of matter we have not been able to produce or observe in the laboratory. We have candidate theories to explain how the universe began, or more precisely how the universe came to be in its Big Bang state: hot, dense, and nearly uniform. These theories require one or more new fields -- fields which have never been observed in the laboratory -- to generate the Big Bang state via quantum mechanical processes. Finally, we have found that recently in cosmic history, the universe has come to be dominated by "dark energy", a fluid-like source of energy and pressure which is distinct from dark matter and ordinary matter. We have uncovered the basic ingredients of our universe: dark matter, dark energy, and a quantum mechanical Big Bang. These ingredients are unexpected and we do not understand their fundamental nature. For example, the existence of dark matter tells us that our understanding of particle physics is incomplete: most of the universe is composed of one or more new types of particles, which have not yet been found by particle physicists. Our next challenge is to elucidate the fundamental nature of dark matter, dark energy, and the Big Bang, using powerful new experiments. If we can understand _why_ these ingredients exist, and how they are connected to the rest of physics, we will have succeeded in understanding the birth of our universe and its evolution from the Big Bang to now, one of the oldest and deepest mysteries in science. My own research is centered on analyzing data from new experiments. I am participating in the Planck mission, a European satellite experiment which is making groundbreaking measurements of the cosmic microwave background (CMB). I am also a member of the HSC collaboration, a new experiment which will measure statistical properties of galaxies using a new Japanese-built camera on the 8-meter Subaru telescope in Hawaii. In addition to direct participation in large experiments, I also study theoretical, statistical, and computational questions which are directly related to analysis of future datasets. In cosmology, our basic tool for understanding the universe is statistical analysis of large datasets, such as maps of galaxies throughout the universe. The statistical procedures are extremely complicated, and each generation of experiments brings new challenges. To some extent these challenges can be anticipated in advance, and I am broadly interested in developing statistical machinery which will be used to analyze a wide range of experiments in the future. My proposal focuses on data analysis within the Planck and HSC experiments, and attacking unsolved statistical problems which will have broad impact within the field as a whole. As one of several examples, I am developing a general software package which will allow researchers in the field to run supercomputer simulations of the universe which correspond to different models of the Big Bang, providing a fundamental tool for studying Big Bang physics. The research in my proposal will play a critical role in our efforts to understand how our universe began and evolved, and it is inspiring to think that we may unravel these mysteries in the not-too-distant future.