Backreaction in Acoustic Black Holes
  The backreaction equations for the linearized quantum fluctuations in an acoustic black hole are given. The solution near the horizon, obtained within a dimensional reduction, indicates that acoustic black holes, unlike Schwarzschild ones, get cooler as they radiate phonons. They show remarkable analogies with near-extremal Reissner-Nordstrom black holes. 
Roberto Balbinot, Serena Fagnocchi, Alessandro Fabbri, Giovanni P.   Procopio