Chiral gravitational effect in time-dependent backgrounds

Gravitational counterpart of the chiral magnetic effect, which is referred as gravitational can also be interest in a cosmological setup. In this study, we investigate effect time-dependent asymmetric fermion background and expanding spacetime by formulating effective action waves. We analyze anomaly equation to see how backreaction from waves thermal plasma occurs. find that non-trivial time dependence chemical potential, induced some scenarios baryogenesis, key ingredient effect. It turns out "memory" imprinted on high frequency propagating plasma. Cosmological implications potential effects wave observation are briefly discussed.