Continuous Variable Quantum Cryptography - beating the 3 dB loss limit
  We demonstrate that secure quantum key distribution systems based on continuous variables implementations can operate beyond the apparent 3 dB loss limit that is implied by the beam splitting attack . The loss limit was established for standard minimum uncertainty states such as coherent states. We show that by an appropriate postselection mechanism we can enter a region where Eve's knowledge falls behind the information shared between Alice and Bob even in the presence of substantial losses. 
Ch. Silberhorn, T. C. Ralph, N. L\"utkenhaus, and G. Leuchs