Probing the origin of our universe through primordial gravitational waves by Ali CMB project

Gravitational waves （GW）, which were predicted by Einstein in 1916 based on the classical theory of General Relativ- ity （GR）, were recently detected by LIGO [1]. This break- through is expected to initiate a novel probe of cosmology, the nature of gravity as well as fundamental physics. In general, signals of GWs can be classified into two categories, which are waves from astro-physical and cosmological sources re- spectively. Accordingly, a number of astronomical and cos- mological experiments are under design across the world [2]. In particular, China is playing a very important role in this field by strengthening a series of fundamental scientific sub- iects, such as cosmic evolution, structure of matter,

Gravitational waves(GW),which were predicted by Einstein in 1916 based on the classical theory of General Relativity(GR),were recently detected by LIGO[1].This breakthrough is expected to initiate a novel probe of cosmology,the nature of gravity as well as fundamental physics.In general,signals of GWs can be classified into two categories。