My research interest is to unveil the nature of dark matter (DM). My expertise covers particle physics and astrophysics/cosmology. My current research consists of the following two aspects:

1) I investigate how microscopic properties of DM affect structure formation of the Universe, to reveal the nature of DM from cosmological observations. This novel approach is called the gravitational probe of DM and can probe interactions within a sector containing DM (dark sector). This is complementary to intensity-frontier experiments probing interactions between the dark and standard-model sectors.

2) I propose novel DM scenarios beyond weakly interacting massive particles (WIMPs). Beyond-WIMP DM solves possible issues of structure formation in the conventional cosmological model (collisionless cold dark matter). Beyond-WIMP DM is significantly different from WIMPs in the thermal history of the Universe and underlying physics toward the Planck scale.