Effective field theory of magnetohydrodynamics from generalized global symmetries

TL;DR

This paper develops an effective field theory framework for non-dissipative magnetohydrodynamics based on generalized global symmetries, introducing a dual photon and systematically incorporating conserved helicities and higher-derivative corrections.

Contribution

It presents a novel effective action for magnetohydrodynamics rooted in generalized global symmetries, including a dual photon and extensions to force-free electrodynamics.

Findings

Formulation of an effective action for non-dissipative MHD

Systematic inclusion of conserved helicities

Extension to higher-derivative corrections

Abstract

We introduce an effective action for non-dissipative magnetohydrodynamics. A crucial guiding principle is the generalized global symmetry of electrodynamics, which naturally leads to introducing a "dual photon" as the degree of freedom responsible for the electromagnetic component of the fluid. The formalism includes additional degrees of freedom and symmetries which characterize the hydrodynamic regime. By suitably enhancing one of the symmetries, the theory becomes force-free electrodynamics. The symmetries furthermore allow to systematize local and non-local conserved helicities. We also discuss higher-derivative corrections.