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dft_tools/doc/tutorials/python/ipt/mott.py

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# Visualization of the Mott transition
from math import *
import os
import numpy
from pytriqs.gf.local import *
from pytriqs.gf.local import Omega, SemiCircular, inverse
from pytriqs.archive import *
from pytriqs.plot.mpl_interface import oplot
import matplotlib.pyplot as plt
import ipt
beta = 40 # Inverse temperature
U = numpy.arange(0,4.05,0.1) # Range of interaction constants to scan
t = 0.5 # Scaled hopping constant on the Bethe lattice
N_loops = 20 # Number of DMFT loops
# Pade-related
DOSMesh = numpy.arange(-4,4,0.02) # Mesh to plot densities of states
eta = 0.00 # Imaginary frequency offset to use with Pade
Pade_L = 201 # Number of Matsubara frequencies to use with Pade
# Bare Green's function of the Bethe lattice (semicircle)
def Initial_G0(G0):
G0 <<= SemiCircular(2*t)
# Self-consistency condition
def Self_Consistency(G0,G):
G0['0'] <<= inverse(Omega - (t**2)*G['0'])
# Save results to an HDF5-archive
ar = HDFArchive('Mott.h5','w')
ar['beta'] = beta
ar['t'] = t
# List of files with DOS figures
DOS_files=[]
# Scan over values of U
for u in U:
print "Running DMFT calculation for beta=%.2f, U=%.2f, t=%.2f" % (beta,u,t)
ipt.run(N_loops = N_loops, beta=beta, U=u, Initial_G0=Initial_G0, Self_Consistency=Self_Consistency)
# The resulting local GF on the real axis
g_real = GfReFreq(indices = [0], beta = beta, mesh_array = DOSMesh, name = '0')
G_real = BlockGf(name_list = ('0',), block_list = (g_real,), make_copies = True)
# Analytic continuation with Pade
G_real['0'].set_from_pade(ipt.S.G['0'], N_Matsubara_Frequencies=Pade_L, Freq_Offset=eta)
# Save data to the archive
ar['U' + str(u)] = {'G0': ipt.S.G0, 'G': ipt.S.G, 'Sigma': ipt.S.Sigma, 'G_real':G_real}
# Plot the DOS
fig = plt.figure()
oplot(G_real['0'][0,0], RI='S', name="DOS", figure = fig)
# Adjust 'y' axis limits accordingly to the Luttinger sum rule
fig.axes[0].set_ylim(0,1/pi/t*1.1)
# Set title of the plot
fig_title = "Local DOS, IPT, Bethe lattice, $\\beta=%.2f$, $U=%.2f$" % (beta,u)
plt.title(fig_title)
# Save the figure as a PNG file
DOS_file = "DOS_beta%.2fU%.2f.png" % (beta,u)
fig.savefig(DOS_file, format="png", transparent=False)
DOS_files.append(DOS_file)
plt.close(fig)
# Create an animated GIF
# (you need to have 'convert' utility installed; it is a part of ImageMagick suite)
convert_cmd = "convert -delay 25 -loop 0"
convert_cmd += " " + ' '.join(DOS_files)
convert_cmd += " " + "DOS.gif"
print "Creating an animated DOS plot..."
os.system(convert_cmd)