Comment on "Gain-assisted Superluminal Light Propagation"
  Wang, Kuzmich and Dogariu, in their 20 July, 2000, Nature article, describe an experiment ostensibly measuring superluminal speeds of 310c via a few percent shift in time of an optical pulse undergoing anomalous dispersion in a pumped medium. This paper seems to have become part of the superluminal lore and is often referenced as a profound example of superluminality. We have closely examined the article and find serious flaws that need to be addressed. 
Harry I. Ringermacher (General Electric Research Center, Schenectady,   NY) and Lawrence R. Mead (Dept. of Physics and Astro...