As one of the most influential experiments on the development of modernmacroscopic theory from Newtonian mechanics to Einstein's special theory ofrelativity, the phenomenon of light dragging in a moving medium has beendiscussed and observed extensively in different types of systems. To have asignificant dragging effect, the long duration of light travelling in themedium is preferred. Here we demonstrate a light-dragging experiment in anelectromagnetically induced transparent cold atomic ensemble and enhance thedragging effect by at least three orders of magnitude compared with theprevious experiments. With a large enhancement of the dragging effect, werealize an atom-based velocimeter that has a sensitivity two orders ofmagnitude higher than the velocity width of the atomic medium used. Such ademonstration could pave the way for motional sensing using the collectivestate of atoms in a room temperature vapour cell or solid state material.
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