import numpy as np

a1 = 1.0 + 0.0j
a2 = 0.0 + 0.0j
T = 0.9
K = 0.1
t = np.sqrt(T) + 0.0j
k = 0.0 - 1j * np.sqrt(K)

Coupler = np.array([[t, k], [k.conjugate(), -t.conjugate()]])

num_cycle = 1000
a = np.zeros((num_cycle, 2), dtype=complex)
b = np.zeros((num_cycle, 2), dtype=complex)

a[0, 0] = a1
a[0, 1] = a2

for n in range(num_cycle):
    pass