Axion Induced Oscillating Electric Dipole Moments

TL;DR

The paper discusses how axion fields induce oscillating electric dipole moments in particles, proposing new experimental avenues for axion dark matter detection based on these effects.

Contribution

It demonstrates that axion electromagnetic anomalies cause oscillating electric dipoles in static magnetic dipoles, a novel low energy theorem with potential experimental implications.

Findings

Electron acquires oscillating electric dipole of frequency m_a

Dipole strength is ~10^{-32} e-cm, above nucleon levels

Within four orders of magnitude of current standard model limits

Abstract

The axion electromagnetic anomaly induces an oscillating electric dipole for {\em any} static magnetic dipole. Static electric dipoles do not produce oscillating magnetic moments. This is a low energy theorem which is a consequence of the space-time dependent cosmic background field of the axion in the limit that it is only locally time dependent $(\overrightarrow{\beta}=0)$. The electron will acquire an oscillating electric dipole of frequency $m_a$ and strength $\sim 10^{-32}$ e-cm, three orders of magnitude above the nucleon, and within four orders of magnitude of the present standard model DC limit. This may suggest sensitive new experimental venues for the axion dark matter search.