Improvement of measurement accuracy in SU(1,1) interferometers
  We consider an SU(1,1) interferometer employing four-wave mixers that is fed with two-mode states which are both coherent and intelligent states of the SU(1,1) Lie group. It is shown that the phase sensitivity of the interferometer can be essentially improved by using input states with a large photon-number difference between the modes. 
C. Brif and Y. Ben-Aryeh (Technion)