Create bands_of_SSH_model_with_two_kinds_of_fourier_transform.py

academic_codes/2021.07.29_bands_of_SSH_model_with_two_kinds_of_fourier_transform/bands_of_SSH_model_with_two_kinds_of_fourier_transform.py

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+import numpy as np
+from math import *
+import cmath
+import guan
+
+v=0.6
+w=1
+k = np.linspace(-pi ,pi, 100)
+
+def hamiltonian_1(k):
+    matrix = np.zeros((2, 2), dtype=complex)
+    matrix[0,1] = v+w*cmath.exp(-1j*k)
+    matrix[1,0] = v+w*cmath.exp(1j*k)
+    return matrix
+
+def hamiltonian_2(k):
+    matrix = np.zeros((2, 2), dtype=complex)
+    matrix[0,1] = v*cmath.exp(1j*k/2)+w*cmath.exp(-1j*k/2)
+    matrix[1,0] = v*cmath.exp(-1j*k/2)+w*cmath.exp(1j*k/2)
+    return matrix
+
+E_1 = guan.calculate_eigenvalue_with_one_parameter(k, hamiltonian_1)
+guan.plot(k, E_1, xlabel='k', ylabel='E_1')
+
+E_2 = guan.calculate_eigenvalue_with_one_parameter(k, hamiltonian_2)
+guan.plot(k, E_2, xlabel='k', ylabel='E_2')