Hotter than infinity: Light pulses can behave like an exotic gas

In our modern society huge amounts of data are transmitted every day, mainly as short optical pulses propagating through glass fibers. With the steadily increasing density of such optical signals, their interaction grows, which can lead to data loss. Physicists are now investigating how to control large numbers of optical pulses as precisely as possible to reduce the effect of such interactions. To this end they have monitored an ensemble of optical pulses as they propagated through an optical fiber and have found that it follows fixed rules -- albeit mainly those of thermodynamics.