Hawking radiation with dispersion versus breakdown of the WKB approximation
Hawking radiation with dispersion versus breakdown of the WKB approximation
Inspired by the condensed matter analogues of black holes (a.k.a. dumb holes), we study Hawking radiation in the presence of a modified dispersion relation which becomes superluminal at large wave numbers. In the usual stationary coordinates $(t,x)$, one can describe the asymptotic evolution of the wave packets in WKB, but …