Sub- and super-radiance over macroscopic distances using a perfect lens   with negative refraction
  Two atoms put at the foci of a perfect lens [J.B. Pendry, Phys. Ref. Lett. 85, 3966 (2000)] are shown to exhibit perfect sub- and super-radiance even over macroscopic distances limited only by the propagation length in the free-space decay time. If the left-handed material forming the perfect lens has nearly constant negative refraction and vanishing absorption over a spectral range larger than the natural linewidth, the imaginary part of the retarded Greens-function between the two focal points is identical to the one at the same spatial position and the atoms undergo a Markovian dynamics. Collective decay rates and level shifts are calculated from the Greens-function of the Veselago-Pendry lens and limitation as well as potential applications are discussed. 
Juergen Kaestel and Michael Fleischhauer