A Feynman diagram visualizes interactions between subatomic particles in quantum field theory. Different line styles represent different particle types: straight lines for fermions (electrons, quarks), wavy lines for photons, curly/looped lines for gluons, and dashed lines for scalar bosons (e.g., Higgs). Lines meet at vertices representing interaction points. Invented by Richard Feynman, these diagrams are both a computational tool and a cultural icon of modern physics.
""" anyplot.ai
feynman-basic: Feynman Diagram for Particle Interactions
Library: plotnine 0.15.5 | Python 3.13.13
Quality: 90/100 | Updated: 2026-06-03
"""
import os
import sys
# This file is named plotnine.py; remove its directory from sys.path so the
# installed plotnine package is found instead of this script.
_here = os.path.abspath(os.path.dirname(__file__))
sys.path = [p for p in sys.path if os.path.abspath(p or ".") != _here]
del _here
import numpy as np
import pandas as pd
from plotnine import (
aes,
annotate,
arrow,
coord_fixed,
element_rect,
element_text,
geom_path,
geom_point,
geom_segment,
geom_text,
ggplot,
labs,
scale_color_manual,
scale_x_continuous,
scale_y_continuous,
theme,
theme_void,
)
# Theme-adaptive chrome tokens (Imprint palette, canonical)
THEME = os.getenv("ANYPLOT_THEME", "light")
PAGE_BG = "#FAF8F1" if THEME == "light" else "#1A1A17"
INK = "#1A1A17" if THEME == "light" else "#F0EFE8"
INK_SOFT = "#4A4A44" if THEME == "light" else "#B8B7B0"
INK_MUTED = "#6B6A63" if THEME == "light" else "#A8A79F"
# Particle type colors — Imprint palette positions 1–4, canonical order
COL_FERMION = "#009E73" # position 1 — brand green (electrons, muons)
COL_PHOTON = "#C475FD" # position 2 — lavender (virtual photon)
COL_GLUON = "#4467A3" # position 3 — blue (gluon leg in legend)
COL_BOSON = "#BD8233" # position 4 — ochre (scalar boson leg in legend)
# Main diagram: e- e+ -> gamma -> mu- mu+
# Vertex positions
v1x, v1y = 3.0, 3.5
v2x, v2y = 7.0, 3.5
# Fermion segments with correct Feynman arrow conventions:
# Particles (e-, mu-): arrows forward in time (left to right)
# Antiparticles (e+, mu+): arrows backward in time (right to left)
fermion_particles = pd.DataFrame({"x": [0.5, v2x], "y": [5.8, v2y], "xend": [v1x, 9.5], "yend": [v1y, 5.8]})
fermion_antiparticles = pd.DataFrame({"x": [v1x, 9.5], "y": [v1y, 1.2], "xend": [0.5, v2x], "yend": [1.2, v2y]})
# Fermion labels positioned near line endpoints
fermion_labels = pd.DataFrame(
{"x": [0.3, 0.3, 9.7, 9.7], "y": [6.25, 0.75, 6.25, 0.75], "label": ["e⁻", "e⁺", "μ⁻", "μ⁺"]}
)
# Wavy photon propagator between vertices
n_waves, amp = 7, 0.35
n_pts = n_waves * 40
t_ph = np.linspace(0, 1, n_pts)
photon_df = pd.DataFrame({"x": v1x + (v2x - v1x) * t_ph, "y": v1y + amp * np.sin(2 * np.pi * n_waves * t_ph)})
# Photon label
photon_label = pd.DataFrame({"x": [(v1x + v2x) / 2], "y": [v1y + 0.75], "label": ["γ"]})
# Vertex interaction dots
vertex_df = pd.DataFrame({"x": [v1x, v2x], "y": [v1y, v2y], "ptype": ["vertex", "vertex"]})
# Legend: four particle line styles at the bottom
leg_y = -0.5
leg_len = 1.5
leg_fermion = pd.DataFrame({"x": [0.3], "y": [leg_y], "xend": [0.3 + leg_len], "yend": [leg_y]})
t_lp = np.linspace(0, 1, 120)
leg_photon_df = pd.DataFrame({"x": 2.8 + leg_len * t_lp, "y": leg_y + 0.2 * np.sin(2 * np.pi * 4 * t_lp)})
t_gl = np.linspace(0, 1, 400)
n_loops = 7
gluon_base_x = 5.5 + leg_len * t_gl
gluon_loop_x = 0.12 * np.sin(2 * np.pi * n_loops * t_gl)
gluon_loop_y = 0.35 * np.abs(np.sin(np.pi * n_loops * t_gl))
leg_gluon_df = pd.DataFrame({"x": gluon_base_x + gluon_loop_x, "y": leg_y - 0.05 + gluon_loop_y})
leg_boson = pd.DataFrame({"x": [8.0], "y": [leg_y], "xend": [8.0 + leg_len], "yend": [leg_y]})
legend_labels = pd.DataFrame(
{
"x": [0.3 + leg_len / 2, 2.8 + leg_len / 2, 5.5 + leg_len / 2, 8.0 + leg_len / 2],
"y": [leg_y - 0.65] * 4,
"label": ["Fermion", "Photon", "Gluon", "Scalar Boson"],
}
)
# Time axis indicator
time_arrow_df = pd.DataFrame({"x": [1.5], "y": [0.3], "xend": [8.5], "yend": [0.3]})
time_label_df = pd.DataFrame({"x": [5.0], "y": [0.7], "label": ["time"]})
# Build plot using plotnine grammar of graphics
plot = (
ggplot()
# Particle fermion lines (arrows forward in time)
+ geom_segment(
data=fermion_particles,
mapping=aes(x="x", y="y", xend="xend", yend="yend"),
size=2.0,
color=COL_FERMION,
arrow=arrow(length=0.18, type="closed"),
)
# Antiparticle fermion lines (arrows backward in time)
+ geom_segment(
data=fermion_antiparticles,
mapping=aes(x="x", y="y", xend="xend", yend="yend"),
size=2.0,
color=COL_FERMION,
arrow=arrow(length=0.18, type="closed"),
)
# Photon wavy propagator
+ geom_path(data=photon_df, mapping=aes(x="x", y="y"), size=2.0, color=COL_PHOTON)
# Vertex interaction points
+ geom_point(data=vertex_df, mapping=aes(x="x", y="y", color="ptype"), size=8, show_legend=False)
+ scale_color_manual(values={"vertex": INK})
# Particle labels
+ geom_text(
data=fermion_labels, mapping=aes(x="x", y="y", label="label"), size=4, color=COL_FERMION, fontweight="bold"
)
+ geom_text(
data=photon_label, mapping=aes(x="x", y="y", label="label"), size=4, color=COL_PHOTON, fontweight="bold"
)
# Time axis arrow
+ geom_segment(
data=time_arrow_df,
mapping=aes(x="x", y="y", xend="xend", yend="yend"),
size=0.8,
color=INK_SOFT,
arrow=arrow(length=0.1, type="open"),
)
+ geom_text(
data=time_label_df, mapping=aes(x="x", y="y", label="label"), size=3, color=INK_MUTED, fontstyle="italic"
)
# Legend: fermion (solid + arrow)
+ geom_segment(
data=leg_fermion,
mapping=aes(x="x", y="y", xend="xend", yend="yend"),
size=1.5,
color=COL_FERMION,
arrow=arrow(length=0.1, type="closed"),
)
# Legend: photon (wavy)
+ geom_path(data=leg_photon_df, mapping=aes(x="x", y="y"), size=1.5, color=COL_PHOTON)
# Legend: gluon (curly loops)
+ geom_path(data=leg_gluon_df, mapping=aes(x="x", y="y"), size=1.5, color=COL_GLUON)
# Legend: scalar boson (dashed)
+ geom_segment(
data=leg_boson,
mapping=aes(x="x", y="y", xend="xend", yend="yend"),
size=1.5,
color=COL_BOSON,
linetype="dashed",
)
# Legend text labels (size=3.5 — slightly larger than previous for legibility)
+ geom_text(data=legend_labels, mapping=aes(x="x", y="y", label="label"), size=3.5, color=INK_SOFT)
# Process subtitle annotation
+ annotate("text", x=5.0, y=6.8, label="e⁻e⁺ → γ → μ⁻μ⁺", size=3.5, color=INK_SOFT, fontstyle="italic")
+ scale_x_continuous(limits=(-0.5, 10.5), expand=(0, 0.2))
+ scale_y_continuous(limits=(-1.5, 7.5), expand=(0, 0.1))
+ coord_fixed(ratio=1)
+ labs(title="feynman-basic · python · plotnine · anyplot.ai")
+ theme_void()
+ theme(
figure_size=(8, 4.5),
plot_title=element_text(size=12, ha="center", fontweight="bold", margin={"b": 8}, color=INK),
plot_background=element_rect(fill=PAGE_BG, color=PAGE_BG),
plot_margin=0.02,
)
)
plot.save(f"plot-{THEME}.png", dpi=400, width=8, height=4.5, units="in", verbose=False)
Part of Feynman Diagram for Particle Interactions on anyplot.ai.