.. _sphx_glr_dimer_lattice_plot_shape_gf.py:


Form of the Greens Functions
============================




.. code-block:: python

    # Author: Óscar Nájera

    from __future__ import (absolute_import, division, print_function,
                            unicode_literals)

    from math import log, ceil
    import matplotlib.pyplot as plt
    import numpy as np

    import dmft.common as gf
    import dmft.ipt_imag as ipt
    import dmft.dimer as dimer


    def ipt_u_tp(u_int, tp, beta, seed='ins'):
        tau, w_n = gf.tau_wn_setup(dict(BETA=beta, N_MATSUBARA=2**8))
        tau, w_n = gf.tau_wn_setup(
            dict(BETA=beta, N_MATSUBARA=max(2**ceil(log(8 * beta) / log(2)), 256)))
        giw_d, giw_o = dimer.gf_met(w_n, 0., 0., 0.5, 0.)
        if seed == 'ins':
            giw_d, giw_o = 1 / (1j * w_n + 4j / w_n), np.zeros_like(w_n) + 0j

        giw_d, giw_o, loops = dimer.ipt_dmft_loop(
            beta, u_int, tp, giw_d, giw_o, tau, w_n, 1e-7)
        g0iw_d, g0iw_o = dimer.self_consistency(
            1j * w_n, 1j * giw_d.imag, giw_o.real, 0., tp, 0.25)
        siw_d, siw_o = ipt.dimer_sigma(u_int, tp, g0iw_d, g0iw_o, tau, w_n)

        return giw_d, giw_o, siw_d, siw_o, g0iw_d, g0iw_o, w_n








Insulator
---------




.. code-block:: python

    u_int = 3.5
    BETA = 85.94
    tp = 0.3
    title = r'IPT lattice dimer $U={}$, $t_\perp={}$, $\beta={}$'.format(
        u_int, tp, BETA)
    giw_d, giw_o, siw_d, siw_o, g0iw_d, g0iw_o, w_n = ipt_u_tp(
        u_int, tp, BETA, 'met')

    plt.figure('G')
    plt.plot(w_n, giw_o.real, 's-')
    plt.plot(w_n, giw_d.imag, 'o-')
    plt.title("Matsubara Greens function")
    plt.xlabel(r'$\omega_n$')
    plt.ylabel(r'$G(\omega_n)$')
    plt.xlim([0, 5])

    plt.figure('G0')
    plt.plot(w_n, g0iw_o.real, 's-')
    plt.plot(w_n, g0iw_d.imag, 'o-')
    plt.title("Matsubara Weiss Field")
    plt.xlabel(r'$\omega_n$')
    plt.ylabel(r'$G^0(\omega_n)$')
    plt.xlim([0, 5])
    plt.show()



.. rst-class:: sphx-glr-horizontal


    *

      .. image:: /dimer_lattice/images/sphx_glr_plot_shape_gf_001.png
            :scale: 47

    *

      .. image:: /dimer_lattice/images/sphx_glr_plot_shape_gf_002.png
            :scale: 47




**Total running time of the script:** ( 0 minutes  0.212 seconds)



.. container:: sphx-glr-footer


  .. container:: sphx-glr-download

     :download:`Download Python source code: plot_shape_gf.py <plot_shape_gf.py>`



  .. container:: sphx-glr-download

     :download:`Download Jupyter notebook: plot_shape_gf.ipynb <plot_shape_gf.ipynb>`

.. rst-class:: sphx-glr-signature

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