利用关联 *** 作计算磁化率

利用关联 *** 作计算磁化率

零温格林函数的计算：

import numpy as np
from numpy import pi
import matplotlib.pyplot as plt
from scipy.signal import correlate

a=1
t=1
nk = 1024
Omega = 0
delta = 0.05
T = 0.01
Ek = np.zeros((nk, nk))
for i in range(nk):
    for j in range(nk):
        Ek[i, j] = -2*t*(np.cos(2*pi*i/nk)+np.cos(2*pi*j/nk))


Gk = (1/(Omega - Ek +1j*delta))
chi0 = correlate(Gk, Gk, mode='same', method='auto')/(nk*nk)
print(chi0.shape)
plt.pcolormesh(np.real(chi0))
plt.colorbar()
plt.show()

可以推广到任意格子，一般图形为平行四边形。 

有限温度的磁化率

 多带情况下：