Galilean Invariance in the Characterization of Light Drag in Moving Atomic Vapor

Light experiences drag effects when it propagates through a moving medium. The study of light drag has provided foundational insights into light-matter interactions. While longitudinal drag has been extensively characterized, transverse drag, where the medium moves perpendicular to the light's propagation, is subtler and requires advanced techniques for detection. In this work, we experimentally investigate transverse drag in a highly dispersive slow-light medium using non-degenerate Zeeman electromagnetically induced transparency (EIT) in rubidium vapor. By systematically comparing configurations where the light beam and the medium serve as the moving frame, we leverage Galilean invariance to analyze transverse light-drag in this optical context. Thus, we provide a platform for future tests of fundamental principles on strong experimental grounds, which offers promising applications in precision velocimetry, accelerometry, quantum information, and light storage technologies.