Abstract:
Gaussian states have risen to a privileged position as a result of their actively pursued
experimental discoveries. When Gaussian modulated coherent state quantum key distribution
(QKD) with homodyne detection is compared to discrete variable QKD,it has been
proven to be a secure method of practical quantum cryptography with great e ciency. I
studied theoretically Gaussian modulated continuous variable quantum key distribution in
my thesis after introducing basics connected to continuous variable systems. I computed the
covariance matrices for the states in order to do additional operations on them. I noticed the
di erence in secure key rate and Holevo information in both the cases when Eve is present
or absent on the transmission channel. I looked at this development of continuous quantum
variables in quantum information by using electromagnetic eld quadrature amplitudes. Finally,
I was able to properly manage the protocol with Gaussian states, resulting in secure
key distribution between the two sides.
