misc

• Errata of some of my papers.
• Solutions to some of H. Goldstein’s Classical Mechanics book problems.
• Some useful equations in Atomic Physics.
• A conversion chart for squeezing in different units.
• ∇ in cylindrical and spherical coordinates.
• The classical version of a and a^†.
• The normal ordered form of (a+a^†)ⁿ.
• An identity involving the imaginary error function erfi(x) (with Aaron Goldberg).
• A collection of short stories by Tomás Carrasquilla

# Things to put at the beginning of a jupyter notebook
import numpy as np
import matplotlib.pyplot as plt
%config InlineBackend.figure_formats=['svg']
%load_ext autoreload
%autoreload 2
np.set_printoptions(linewidth=200)
#plt.style.use('ggplot')
#from matplotlib import rcParams
#rcParams['font.family'] = 'serif'
#rcParams['font.sans-serif'] = ['Computer Modern Roman']

GaussianIntegrator[{coeff_, exp_}, var_] := 
 Module[{a, b, c, aa, bb, cc},
  {c, b, a} = Series[exp + aa var^2 + var bb + cc, {var, 0, 2}][[3]];
  {coeff Sqrt[\[Pi]/-a], (b^2)/(-4 a) + c} /. {aa -> 0, bb -> 0, 
    cc -> 0}]

gi=GaussianIntegrator

psi[n_,x_]:=Sqrt[1/(2^n n! Sqrt[Pi])] Exp[-x^2/2] HermiteH[n,x]