Talks

Abstract: “How did our universe begin?” is possibly one of the oldest questions that have bewildered humans throughout history. As a theoretical cosmologist, our job is to find a mathematically consistent picture for early universe that could explain observations, from the largest to the smallest scales. The past thirty years have witnessed amazing progress, both in developing technology for precision cosmological observations, and in perfecting mathematical methodology to explain them. For example, ripples in cosmic geometry are now measured with the precision of one part in a million. We also have sophisticated mathematical frameworks such as general relativity and quantum theories that describe the origin of these ripples in early universe. However, with all of these extraordinary achievements, some old and new puzzles remain unsolved. For example we still have not resolved the most crucial puzzle about the origin of cosmos, namely the Big Bang Singularity problem. We will take a journey back in time to explore the fascinating realm of early universe and some of its mysteries.

Abstract: From astronomical observations, we know that the state of the early universe (just after the Big Bang) was extremely simple. This is surely an important clue about how the universe began, but what exactly is it trying to tell us? I will explain our new answer to this question: we think it is telling us that the universe before the bang is a kind of mirror image of the universe after the bang (they are related by "CPT symmetry"). (Based on recent work with Kieran Finn and Neil Turok: https://arxiv.org/pdf/1803.08928.pdf)