Center for Theoretical Physics of the Universe (CTPU-PTC)

CMB spectral distortions as a probe of cosmology

by Dr Hiroyuki Tashiro (Nagoya University)

Measuring the spectral deviation of the cosmic microwave background (CMB) from the blackbody spectrum is very attractive as a probe of the thermal history of the Universe. To probe the physics in the early universe and to open an observational window for new physics, various energy release mechanisms both in and beyond standard cosmology need to be studied. In this talk, I provide a revi! ew of the physics of CMB distortions and the energy release that creates CMB distortions in the early universe. Additionally I propose a new test of the energy independency of the redshift effect by the measurement of the spectral distortions. In GR, the energy independency of the redshift effect is ensured by the FRW metric which does not depend on energy. We show that the CMB spectral distortions arise when the FRW metric has the energy dependence. Our result is consistent with no energy-dependence of the redshift effect, at least, with a precision of $10^{−6}$ on the CMB energy scales.