Title: CMB & power asymmetry anomaly & multi-speed inflation

Speaker: Professor Yifu Cai
Institute: University of Science and Technology of China
Time: 2017.04.06（Thursday） 14:30
Place: Physics Building 573, Haiyun Campus, Xiamen University
Abstract: The measurement of the Cosmic Microwave Background (CMB) radiation is one of the most significant cosmological survey to date. With its help, cosmologists are able to explore the nature of the primordial universe. The underlying physics mechanism, which connects primordial cosmological fluctuations predicted by inflation models and the CMB anisotropies observed in experiments, is the renowned Cosmological Perturbation Theory (CPT), and this theory can be simply described by the so-called δN formalism. However, the standard CPT paradigm can not explain the hemispherical asymmetry as observed by the latest Planck data as well as the earlier WMAP data. To address this observational issue, we propose a model of multi-speed inflation and based on this model, we are able to generalize the δN formalism by including the modulation of primordial sound speed parameter. We give an example to demonstrate how such a perturbation theory can be applied to falsify early universe inflation models when compared with observations.