Comment on ``Manipulating the frequency entangled states by an   acoutic-optical modulator''
  A recent theoretical paper [1] proposes a scheme for entanglement swapping utilizing acousto-optic modulators without requiring a Bell-state measurement. In this comment, we show that the proposal is flawed and no entanglement swapping can occur without measurement. 
K.J. Resch, S.H. Myrskog, J.S. Lundeen, and A.M. Steinberg