Beltrami fields, dispersive electromagnetic waves and gravitational spheromaks from chiral anomaly
Résumé
In this note we focus on the backreaction effects due to the chiral anomaly. The chiral anomaly gives rise to certain modifications in the conserved currents. In the case of the Maxwell gauge fields there appears a new contribution to the electric current proportional to the background magnetic field. This phenomenon is known as the chiral magnetic effect and it is widely discussed in the current literature. In the case of the gravitational field, the anomaly, as we show here, induces a new contribution to the stress-energy tensor. We analyze the possible manifestations of these modifications in the gravitational field and in hydrodynamics in the chiral media. We also make some comments regarding the backreaction effects in electrodynamics in the chiral media. In each of these directions we observe the systematical appearance of the Beltrami type fields. In electrodynamics or in hydrodynamics the Beltrami field (e.g., magnetic field or fluid velocity) is a vector that is parallel to its own curl. We suggest a generalization of the Beltrami fields for the tensorial gravitational perturbations. The respective solutions to the gravitational equations we call gravitational spheromaks by analogy with a similar phenomenon in electrodynamics. In the modified hydrodynamics in the chiral media the vorticity is asymptotically a Beltrami vector field in a generalized Gromeka-Beltrami flow.
Mots clés
anomaly, chiral
perturbation, gravitation
tensor, energy-momentum
fluid, velocity
current, electric
effect, magnetic
magnetic field, background
wave, electromagnetic
field theory, vector
magnetic field, chiral
Beltrami
electromagnetic field
hydrodynamics
back reaction
flow
gauge field theory
dispersion
conservation law