Testing inflation with new CMB polarization measurements

这个项目解决的问题是，宇宙膨胀是在早期宇宙中发生的吗？如果是这样的话，它将产生一个引力波背景，印在宇宙微波背景的偏振上。在过去的一年里，BICEP2实验看到了一个诱人的偏振信号，但只在一个波长上，然后发现很可能是由于我们银河系的辐射污染。为了取得进展，在牛津，我们是阿塔卡马宇宙学望远镜合作的一部分，ACTPol目前在智利观测CMB。AdvACT将是2016-18年运行的第三代接收器；它将在多个波长下映射半个天空的偏振，并将能够寻找比尚未达到的更小的膨胀信号。该项目将侧重于对可能的B模式偏振信号的理论解释，以及分析技术，包括偏振银河系前景的建模和分离。这项工作还将包括下一代仪器的模拟和准备工作，包括地面‘CMB-S4’项目和LiteBIRD卫星。博士学位的核心部分预计将用于与日本同事在LiteBIRD科学上的合作。

This project addresses the question, 'Did cosmic inflation happen in the early Universe?' If so it would have produced a gravitational wave background, imprinted on the polarization of the Cosmic Microwave Background. In the past year a tantalizing polarized signal was seen by the BICEP2 experiment, but only at a single wavelength, and was then found to be most likely due to contaminating emission from our own Milky Way. To make progress, in Oxford we are part of the Atacama Cosmology Telescope collaboration, with ACTPol currently observing the CMB in Chile. AdvACT will be the third generation receiver in operation 2016-18; it will map half the sky in polarization at multiple wavelengths, and will be able to look for smaller inflationary signals than yet reached.This project will have some emphasis on the theoretical interpretation of the possible B-mode polarization signal, and on analysis techniques including the modeling and separation of polarized Galactic foregrounds. The work will also include simulations and preparations for next generation instruments, including the ground-based 'CMB-S4' project, and the LiteBIRD satellite. A core part of the PhD is anticipated to be spent working with Japanese colleagues on LiteBIRD science.