.. _sphx_glr_auto_examples_Solid_State_Physics_plot_P.py:


Polarization
============

A diagram containing different operators.




.. image:: /auto_examples/Solid_State_Physics/images/sphx_glr_plot_P_001.png
    :align: center





.. code-block:: python

    from __future__ import print_function, division
    import numpy as np
    import matplotlib.pyplot as plt
    from feynman import Diagram

    # Set up the dimensions of the figure and the objects
    d = Diagram(figsize=(8,3))
    d.ax.set_xlim(0, 8/3)
    d.ax.set_ylim(0, 1)

    textpad = 0.25
    opwidth = 0.4
    linlen = 1.1
    Gamma_side = .4
    Gamma_height = Gamma_side * np.sqrt(3) / 2

    # Positon of the first vertex
    x0 = 0.2
    y0 = sum(d.ax.get_ylim()) / 2

    # Define line styles
    G_style = dict(
        style='double elliptic',
        ellipse_excentricity=-1.2, ellipse_spread=.3,
        arrow=True, arrow_param={'width':0.05},
        )

    # Draw the diagram
    v01 = d.vertex([x0, y0])
    v02 = d.vertex(v01.xy, dx=opwidth)
    P = d.operator([v01,v02], c=1.3)
    P.text("$P$")

    d.text(v02.x+textpad, y0, "=", fontsize=30)

    v21 = d.vertex(v02.xy, dx=.4)
    v22 = d.vertex(v21.xy, dx=linlen, dy=Gamma_side/2)
    v23 = d.vertex(v21.xy, dx=linlen, dy=-Gamma_side/2)
    v24 = d.vertex(v21.xy, dx=linlen+Gamma_height)

    l21 = d.line(v22, v21, **G_style)
    l21 = d.line(v21, v23, **G_style)

    Gamma = d.operator([v22,v23, v24])
    Gamma.text("$\Gamma$")

    d.draw()
    plt.show()

**Total running time of the script:** ( 0 minutes  0.025 seconds)



.. only :: html

 .. container:: sphx-glr-footer


  .. container:: sphx-glr-download

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



  .. container:: sphx-glr-download

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


.. only:: html

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

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.readthedocs.io>`_