Stable Causality and Microcausality for Drummond-Hathrell Photons

Madhukar Deb, Jay Desai, Diptimoy Ghosh

Local superluminal photon propagation arises at $\mathcal{O}(\hat{I}\pm /m_e^2)$ in the Drummond Hathrell (DH) effective action obtained by integrating out the electron in QED coupled to gr…