File:Mach-Zehnder photons animation.gif
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Mach-Zehnder_photons_animation.gif (300 × 220 pixels, file size: 110 KB, MIME type: image/gif, looped, 100 frames, 7.0 s)
This file is from Wikimedia Commons and may be used by other projects. The description on its file description page there is shown below.
Summary
DescriptionMach-Zehnder photons animation.gif |
English: Animation of photons in a Mach–Zehnder interferometer. In the empty interferometer each photon interferes with itself. If a detector is placed in the interferometer, the wavefunction will collapse so that the photon is either detected directly or it will move on and split at the second beam splitter without interference. |
Date | |
Source | Own work |
Author | user:Geek3 |
This plot was created with Matplotlib by n.
Source Code
The image is created by the following python source-code. Requirements:
- python
- Matplotlib plotting library
Python Matplotlib source code |
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#!/usr/bin/python
# -*- coding: utf8 -*-
from math import *
import matplotlib.pyplot as plt
from matplotlib.patches import Polygon, Circle, Wedge
from matplotlib import animation
import numpy as np
# settings
fname = 'Mach-Zehnder_photons_animation'
width, height = 300, 220
nframes = 100
nphotons = 12
fps = 15
x0 = 100.5
x1 = 218.5
y0 = 200.5
y1 = 80.5
lx, lw, lh = 5, 46, 21 # laser
dtect = 62.5
t1, t2, tmove = 0.25, 0.9, 0.025
ymove = 24
rp = 2. # photon radius
cp1 = '#ff0000' # photon color
cp2 = '#ffaaaa' # splitphoton color
##
xstart = lx + lw / 2.
dx = x1 - x0
dy = y1 - y0
l = (x0 - xstart) + abs(dx) + abs(dy) + dtect + 2.*rp
xdet0 = (x0 + x1) / 2
fly_frac = 0.7
v = l / fly_frac
tdet0 = (xdet0 + 2.*rp - xstart) / v
tdet12 = l / v
# introduce artificial antibunching for illustration purpose
ptimes = (np.random.random() + np.sort(np.random.random(3*nphotons))[::3]) % 1
photons = [{} for i in range(nphotons)]
for i, p in enumerate(photons):
p['t0'] = ptimes[i]
if t1 <= (p['t0'] + tdet0) % 1 and (p['t0'] + tdet0) % 1 <= t2:
# photon sees first detector
if np.random.randint(2) == 0:
# photon hits extra detector
p['arm'] = 'none'
p['det'] = 0
else:
# photon escapes first detector
p['arm'] = 'lower'
# => random detection at second beam splitter
if np.random.randint(2) == 0:
p['det'] = 1
else:
p['det'] = 2
else:
# photon sees standard Mach-Zehnder interferometer
p['arm'] = 'both'
p['det'] = 1
if p['det'] == 0:
p['tdet'] = (p['t0'] + tdet0) % 1
else:
p['tdet'] = (p['t0'] + tdet12) % 1
p['click_frame'] = int(round(p['tdet'] * nframes)) % nframes
plt.close('all')
mpl.rc('path', snap=False)
def animate(nframe):
# prepare a clean and image-filling canvas for each frame
plt.clf()
fig.gca().set_position((0, 0, 1, 1))
plt.xlim(0, width)
plt.ylim(0, height)
plt.axis('off')
t = float(nframe) / nframes
# photons
for p in photons:
s0 = v * ((t - p['t0']) % 1)
if s0 > l:
continue
s = s0 + start - x0
if s <= 0:
# from laser to first beam splitter
x, y = x0 + s, y0
fig.gca().add_patch(Circle((x, y), rp, color=cp1))
elif s <= abs(dx) + abs(dy):
# in the interferometer
if s < abs(dx):
xu, yu = x0 + copysign(s, dx), y0
else:
xu, yu = x1, y0 + copysign(s - abs(dx), dy)
if s < abs(dy):
xd, yd = x0, y0 + copysign(s, dy)
else:
xd, yd = x0 + copysign(s - abs(dy), dx), y1
if s < xdet0 - x0 or p['arm'] == 'both':
fig.gca().add_patch(Circle((xu, yu), rp, color=cp2))
fig.gca().add_patch(Circle((xd, yd), rp, color=cp2))
elif p['arm'] == 'lower':
fig.gca().add_patch(Circle((xd, yd), rp, color=cp1))
else:
# after the interferometer
x, y = x1 + (s - abs(dx) - abs(dy)), y1
if p['arm'] == 'both':
fig.gca().add_patch(Circle((x, y), rp, color=cp1))
elif p['arm'] == 'lower':
fig.gca().add_patch(Circle((x, y), rp, color=cp2))
x, y = x1, y1 - (s - abs(dx) - abs(dy))
fig.gca().add_patch(Circle((x, y), rp, color=cp2))
# laser
fig.gca().add_patch(
Polygon([[lx, y0-lh/2.], [lx, y0+lh/2.],
[lx+lw, y0+lh/2.], [lx+lw, y0-lh/2.]],
closed=True, facecolor='#cccccc', edgecolor='black'))
plt.text(lx+lw/2., y0-2, 'laser', fontsize=12,
horizontalalignment='center', verticalalignment='center')
# beam splitters
b = 12
fig.gca().add_patch(
Polygon([[x0-b, y0+b], [x0+b, y0+b], [x0+b, y0-b],
[x0-b, y0-b], [x0-b, y0+b], [x0+b, y0-b]],
closed=True, facecolor='#88aadd', edgecolor='black',
linewidth=2, alpha=0.4))
fig.gca().add_patch(
Polygon([[x1-b, y1+b], [x1+b, y1+b], [x1+b, y1-b],
[x1-b, y1-b], [x1-b, y1+b], [x1+b, y1-b]],
closed=True, facecolor='#88aadd', edgecolor='black',
linewidth=2, alpha=0.4))
# mirrors
m, mw = 12, 4
fig.gca().add_patch(
Polygon([[x1-m+mw/2., y0+m+mw/2.], [x1+m+mw/2., y0-m+mw/2.]],
closed=False, edgecolor='#555555', linewidth=mw))
fig.gca().add_patch(
Polygon([[x0-m-mw/2., y1+m-mw/2.], [x0+m-mw/2., y1-m-mw/2.]],
closed=False, edgecolor='#555555', linewidth=mw))
# detectors
c_off = '#cccccc'
c_on = '#cc0000'
c0 = c1 = c2 = c_off
for p in photons:
if p['click_frame'] == nframe:
if p['det'] == 0: c0 = c_on
if p['det'] == 1: c1 = c_on
if p['det'] == 2: c2 = c_on
if t1 <= t and t <= t2:
yd = y0
else:
yd = y0 - min((t1-t)%1, tmove, (t-t2)%1) * ymove / float(tmove)
fig.gca().add_patch(mpl.patches.Wedge((xdet0, yd), b, 270, 90, fc=c0))
fig.gca().add_patch(mpl.patches.Wedge((x1 + dtect, y1), b, 270, 90, fc=c1))
fig.gca().add_patch(mpl.patches.Wedge((x1, y1 - dtect), b, 180, 0, fc=c2))
fig = plt.figure(figsize=(width/100., height/100.))
anim = animation.FuncAnimation(fig, animate, frames=nframes)
anim.save(fname + '.gif', writer='imagemagick', fps=fps)
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Postprocessing with gifsicle:
gifsicle -k 64 --background="#ffffff" -O3 --careful -i < Mach-Zehnder_photons_animation.gif > Mach-Zehnder_photons_animation_.gif
Licensing
I, the copyright holder of this work, hereby publish it under the following licenses:
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License.http://www.gnu.org/copyleft/fdl.htmlGFDLGNU Free Documentation Licensetruetrue |
This file is licensed under the Creative Commons Attribution 3.0 Unported license.
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- to share – to copy, distribute and transmit the work
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Items portrayed in this file
depicts
22 August 2015
image/gif
File history
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Date/Time | Thumbnail | Dimensions | User | Comment | |
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current | 10:30, 22 August 2015 | 300 × 220 (110 KB) | wikimediacommons>Geek3 | {{Information |Description ={{en|1=Animation of photons in a en:Mach–Zehnder interferometer. In the empty interferometer each photon interferes with itself. If a detector is placed in the... |
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GIF file comment | https://commons.wikimedia.org/wiki/File:Mach-Zehnder_photons_animation.gif |
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