Abstract:I will discuss new ideas to directly search for light dark matter, such as the axion or the dark photon, by using quantum sensing techniques with nitrogen-vacancy (NV) centers in diamonds. Based on our previous work 2302.12756, I will demonstrate how the NV center magnetometry works, and how it can be applied to dark matter search. Also, based on some ongoing works, I will demonstrate how we can use the nuclear spin of nitrogens to provide complementary constraints on the axion dark matter, and show my attempts to use them for the purpose of comagnetometry. I will emphasize that the NV centers, being a quantum sensing apparatus, have various possible quantum advantages in sensing a wide range of frequencies and improving sensitivity.