  In this work we focus on evaluating the effectiveness of two non-Gaussian
operations, photon subtraction (PS) and quantum scissors (QS) in terms of
Continuous Variable (CV)-Quantum Key Distribution (QKD) over lossy channels.
Each operation is analysed in two scenarios, one with the operation applied
transmitter-side to a Two-Mode Squeezed Vacuum (TMSV) state and a second with
the operation applied to the TMSV state receiver-side. We numerically evaluate
the entanglement and calculate the QKD key rates produced in all four possible
scenarios. Our results show that for a fixed value of initial squeezing in the
TMSV state, the states produced by the non-Gaussian operations are more robust
to loss, being capable of generating higher key rates for a given loss. More
specifically, we find that for values of initial TMSV squeezing below 1.5dB the
highest key rates are obtained by means of transmitter-QS. On the other hand,
for squeezing above 1.5dB we find that receiver-PS produces higher key rates.
Our results will be important for future CV-QKD implementations over free-space
channels, such as the Earth-satellite channel.
  Accepted for Publication in Quantum Communications and Information Technology
Workshop, IEEE Globecom, HI, USA, December 2019.
