Contribution of the chiral vortical effect to the evolution of the hypermagnetic field and the matter-antimatter asymmetry in the early Universe

TL;DR

This study investigates how the chiral vortical effect influences the evolution of hypermagnetic fields and matter-antimatter asymmetry in the early Universe, highlighting the role of vorticity in magnetic field growth and asymmetry conversion.

Contribution

It introduces a detailed analysis of the chiral vortical effect's impact on hypermagnetic field evolution, extending previous work focused mainly on the chiral magnetic effect.

Findings

Vorticity significantly contributes to hypermagnetic field generation.

Hypermagnetic fields grow from zero only with non-zero vorticity.

Larger initial vorticity leads to quicker saturation and asymmetry conversion.

Abstract

In this paper, we study the contribution of the chiral vortical effect, in addition to that of the chiral magnetic effect, to the evolution of the hypermagnetic field and the matter-antimatter asymmetry in the symmetric phase of the early Universe in the temperature range 100GeV < T < 10TeV. We choose a fully helical Chern-Simons wave configuration for the velocity and the hypermagnetic vector potential fields. The latter makes the plasma force-free in the absence of viscosity. We show that the most pronounced effect of the chiral vorticity is the production and initial growth of the hypermagnetic field. In particular, we show that in the presence of a non-zero matter asymmetry, the hypermagnetic field can grow from zero initial value only in the presence of a non-zero vorticity field. Moreover, we show that larger initial growths not only result in larger maximum values of the hypermagnetic field, but also cause the saturation of the hypermagnetic field and the conversion of the lepton-baryon asymmetry to occur more quickly, i.e., at a higher temperature. We show that the damping of the vorticity due to the presence of viscosity, which typically occurs extremely rapidly, does not significantly affect the evolution.