An effective field theory approach to cosmological structure formation
Abstract/Contents
- Abstract
- One of the main frontiers of observational cosmology is to map out how matter is distributed throughout the universe. The clustering patterns of galaxies and other astrophysical objects contain imprints of the universe's expansion history, the properties of the quantum fluctuations that are believed to have seeded the late-time structures we observe, and possibly other new and exotic physical processes. To extract this information from observations, we require a robust theoretical framework for how gravitational clustering works at large distances. This dissertation presents such a framework, which adapts the ideas of "effective field theory" (originally developed in the context of particle physics and quantum fields) to describe how small perturbations in an initially homogeneous distribution of matter evolve through cosmic time. In this framework, the perturbations are described as an effective fluid at long distances, with a stress tensor that parametrizes the effects of short-wavelength processes on the long-distance dynamics of the fluid. This stress tensor can be written as an expansion in long-wavelength fields (such as the matter overdensity) and spatial derivatives, and the coefficients of this expansion can be matched either to observations or to numerical simulations of gravitational clustering. Through several explicit calculations of correlation functions (particularly the power spectrum) of the cosmic density field, I demonstrate how the presence of this stress tensor renders the theory free of many of the issues that have plagued other perturbative approaches to gravitational clustering. I also perform several comparisons of the theory's predictions to measurements from dark matter-only N-body simulations, demonstrating the theory's ability to reproduce these measurements at over a wider range of scales and at higher precision than previously possible. The results in this dissertation represent significant advances in our understanding of cosmological perturbation theory, and their eventual application to observations of large-scale structure will likely be a great help in furthering our knowledge about the universe we inhabit.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2016 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Foreman, Simon |
|---|---|
| Associated with | Stanford University, Department of Physics. |
| Primary advisor | Senatore, Leonardo |
| Thesis advisor | Senatore, Leonardo |
| Thesis advisor | Kachru, Shamit, 1970- |
| Thesis advisor | Wechsler, Risa H. (Risa Heyrman) |
| Advisor | Kachru, Shamit, 1970- |
| Advisor | Wechsler, Risa H. (Risa Heyrman) |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Simon Foreman. |
|---|---|
| Note | Submitted to the Department of Physics. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2016. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2016 by Simon James Foreman
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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