Group 1 - The mainstream theory of modern cosmology posits that the universe underwent a rapid inflationary phase shortly after its birth, leading to the formation of cosmic structures and the generation of primordial gravitational waves [1] - Primordial gravitational waves carry the core secrets of the universe's birth, with various theoretical models predicting different mechanisms and strengths for their generation [2] - Detecting primordial gravitational waves would provide direct evidence of quantum fluctuations in spacetime and could confirm the existence of gravitons, impacting our understanding of the nature of spacetime [2] Group 2 - The detection of primordial gravitational waves requires specific environmental conditions, with ideal observation sites having median precipitation levels below 2 millimeters [3] - The AliCPT experiment in Tibet, which began scientific observations in April 2025, is currently the largest in terms of effective aperture and number of detectors among similar international telescopes [3] - The exploration of primordial gravitational waves aims to reveal the universe's earliest characteristics, allowing for the "listening" of echoes from 13.8 billion years ago [3]