FTL?

Faster than light?  No, not really.  Wait, let me rephrase that: No, Of Course Not.

On to the article, Much Faster Than Light, which is about hollow core fiber optics.  You see, the speed of light in glass is about 2/3 that in vacuum or (near enough) air.  The resultant ever-so-slight time delay in passing data is significant in high-frequency trading between cities... so hollow core optical fiber is a thing now.  The light moves through air inside of the glass fiber instead of in the glass, which brings the speed back up to 99%+ of c, and there we go.

Something similar, using HF radio comms, was posted here four years ago.  Each approach has its plusses and minuses.  Fiber will be more reliable and have a higher data bandwidth; HF waves will follow a straighter path, you don't have to worry about right-of-ways, and there's no physical infrastructure beyond the two end-point stations.

On one hand, this is technologically cool.  On the other hand, HFT and related shenanigans seem about as big-picture economically productive as counting cards.  I get the feeling that historians and forensic economists will have a field day with all this in a few decades.

So, FTL?  No, just faster than light moving through a slow medium.