Hello! Here are MATLAB-based code packages with functions for calculating the secret key rate when excuting the homodyne detection quadrature phase shift keying continuous-variable quantum key distribution protocol.
The preprint that introduces this protocol is given on PRX Quantum 2, 040334 (arXiv with Num. 2104.11152).
Code 1 and Code 2 are two code packages based on this protocol. They are alternative choices if you want to simulate this protocol.
There is one controller and nine functions:
-> Controller - afin_control.m
This is a function with the key rate as the final output. The inputs are experimental parameters.
-> Function - S_1.m
This is a function to generate all Hermitian matrices in the constraints.
-> Function - S_2.m
This is a function to calculate the value of each constraint.
-> Function - S_3.m
This is a function to generate a primal density matrix \rho_{AB} under the constraints.
-> Function - S_4.m
This is a function to generate the matrices of interval operators in the photon number representation.
-> Function - S_5.m
This is a function to calculate \Del\rho, which is the solution of the primal problem in the step 1.
-> Function - S_6.m
This is a function to search the parameter \lambda that makes the key rate minimum.
-> Function - S_7.m
This is a function to solve the dual problem in step 2.
-> Function - S_8.m
This is a function to calculate the error correction for each quadrature.
-> Function - abstractep.m
This is a function to gain the parameter ep2 used in dual problem.
There is one controller and eleven functions:
-> Controller - protocol_simulation.m
This is a script with the key rate as the final result. It sets the parameters and controls other functions.
-> Function - K_pq_new.m
This is a function to generate Kraus operators in the key rate formula.
-> Function - Gamma.m
This is a function to calculate the constraint matrices.
-> Function - gamma_exp.m
This is a function to calculate the value of each constraint.
-> Function - search_rho0.m
This is a function to generate a primal density matrix \rho_{AB} under the constraints.
-> Function - algorithm1.m
This is a function to do the step 1 (primal problem).
-> Function - abstractep.m
This is a function to gain the parameter eps used in dual problem.
-> Function - G_perturb_deg.m
This function is used to calculte the hermitian conjugate of the perturbed G.
-> Function - G_perturb.m
This function is used to calculte the perturbed G.
-> Function - max_gamma_y.m
This is a function to solve the dual problem in step 2.
-> Function - rel_ent.m
This is a function to calcualte the relative entropy of the inputs.
-> Function - error_correction.m
This is a function to calculate the error correction for each quadrature.