基于离散调制的连续变量量子密钥分发Matlab仿真代码（DM-CV-QKD）

# HD-QPSK-CVQKD 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. # Introduction of Code 1 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. # Introduction of Code 2 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.