infinite_1d_box.py 文件源码

def main():
    print()
    print("Applying perturbation theory to calculate the ground state energy")
    print("of the infinite 1D box of width ``a`` with a perturbation")
    print("which is linear in ``x``, up to second order in perturbation.")
    print()

    x, _a = var("x _a")
    perturbation = .1 * x / _a

    E1 = energy_corrections(perturbation, 1)
    print("Energy for first term (n=1):")
    print("E_1^{(0)} = ", E1[0])
    print("E_1^{(1)} = ", E1[1])
    print("E_1^{(2)} = ", E1[2])
    print()

    E2 = energy_corrections(perturbation, 2)
    print("Energy for second term (n=2):")
    print("E_2^{(0)} = ", E2[0])
    print("E_2^{(1)} = ", E2[1])
    print("E_2^{(2)} = ", E2[2])
    print()

    E3 = energy_corrections(perturbation, 3)
    print("Energy for third term (n=3):")
    print("E_3^{(0)} = ", E3[0])
    print("E_3^{(1)} = ", E3[1])
    print("E_3^{(2)} = ", E3[2])
    print()