The origin of the universe and the Ali primordial gravitational waves detection

The hot Big Bang cosmology has achieved numerous successes in the past decades in describing the evolution of our universe, but several conceptual issues remain to be addressed. Accordingly, a potentially revolutionary breakthrough is expected within modern cosmology in near future. The goal of probing the origin of our universe and its evolution has become one major challenge for scientists around the world, and its importance has be appreciated and highlighted in the recently released 13th Five-Year Plan by Chinese government. Very early universe models, such as inflation and bounce, predicted an existence of primordial gravitational waves (GWs), but these signals have not yet been observed by experiments. Unlike the GW signals originated from black holes as has been detected by the LIGO team, these primordial GWs were pro-duced right after the Big Bang, and hence, would carry fruitful information about the very early universe.In addition, the frequency band of primordial GWs is extremely low, which may open a brand-new window for the next breakthrough of GW detections. In this article, we will briefly introduce the Chinese Ali Project and the associated scientific topics.