Chiral gravitational effect in time-dependent backgrounds

Understand

Gravitational counterpart of the chiral magnetic effect, which is referred as the chiral gravitational effect, can also be of interest in a cosmological setup.

• In this study, we investigate this effect in the time-dependent chiral asymmetric fermion background and in the expanding spacetime by formulating the effective action of gravitational waves.
• We also analyze the anomaly equation to see how the backreaction from gravitational waves to thermal chiral plasma occurs.
• We find that the non-trivial time dependence of chiral chemical potential, which can be induced in some scenarios of baryogenesis, is the key ingredient of the chiral gravitational effect.