Limits on the Carroll-Field-Jackiw electrodynamics from geomagnetic data

TL;DR

This paper derives new, stringent constraints on Lorentz-symmetry violation parameters in electrodynamics using geomagnetic data, significantly improving previous bounds by four orders of magnitude.

Contribution

It provides the first detailed analysis of geomagnetic data to set bounds on the Carroll-Field-Jackiw Lorentz-violating term in electrodynamics.

Findings

Constraints on $(k_{AF})_Z$ are less than $4 imes 10^{-25}$ GeV.

Constraints on $(k_{AF})_X$ and $(k_{AF})_Y$ are less than $10^{-24}$ GeV.

Bounds improve previous limits by about four orders of magnitude.

Abstract

Lorentz-symmetry violation may be described via the CPT-odd, dimension-3, Carroll-Field-Jackiw term, which couples the electromagnetic fields to a constant 4-vector $k_{\rm AF}$ selecting a preferred direction in spacetime. We solve the field equations using the Green's method for a static point-like magnetic dipole and find the $k_{\rm AF}$-dependent corrections to the standard dipolar magnetic field that strongly dominates the near-Earth magnetic field. Given the very good agreement between current models and ground- and satellite-based geomagnetic data, our strongest constraints on the components of $k_{\rm AF}$ in the Sun-centered frame read $|(k_{\rm AF})_Z| \lesssim 4 \times 10^{-25} \, {\rm GeV}$ for $|(k_{\rm AF})_X|, |(k_{\rm AF})_Y| \lesssim 10^{-24} \, {\rm GeV}$ at the two-sigma level. This represents an improvement of about four orders of magnitude over earlier bounds based on other geophysical phenomena.