Unraveling the effect of circularly polarized light on reciprocal media: Breaking time reversal symmetry with non-Maxwellian magnetic-esque fields

Optical rectification of intense, circularly polarized light penetrating a material generates a static magnetization through the inverse Faraday effect and, therefore, a magnetic field aligned with the light's direction of propagation. Recent ultrafast experiments have unveiled a substantial, orders-of-magnitude gap between the observed effective field and theoretical predictions. In this study, we show that the discrepancy arises due to a missing factor on the order of ${\ensuremath{\alpha}}^{\ensuremath{-}2}\ensuremath{\approx}2\ifmmode\times\else\texttimes\fi{}{10}^{4}$, where \ensuremath{\alpha} is the fine-structure constant. We demonstrate that alongside Maxwellian magnetization, circular polarization creates large non-Maxwellian fields that disrupt time reversal symmetry, effectively mimicking authentic magnetic fields within the material while eluding detection externally. These unconventional fields, reaching effective magnitudes as high as 100 T, lead to phenomena akin to Faraday rotation and robustly interact with magnons in magnetically ordered materials.