Update to v0.2:

Added: Comparison of the energy for two different potentials that
  share the same scattering length and integral (new figure).

  Added: Lee-Huang-Yang prediction in figures.

  Fixed: Wrong exponent in definition of correlation function.

  Added: More precise comparison of the big equation prediction for the
  hard core potential (new figure).

  Changed: Miscellaneous minor fixes and clarifications.

figs/hardcore.fig/hardcore_compare.gnuplot

@@ -0,0 +1,36 @@
+set ylabel "energy relative error"
+set xlabel "$\\rho$"
+
+set xtics 1e-6, 100, 1
+set xtics add ("$10^{-6}$" 0.000001, "$10^{-4}$" 0.0001, "$10^{-2}$" 0.01, "$1$" 1.0)
+unset mxtics
+
+set xrange [1e-9:sqrt(2)]
+
+set ytics 1e-5, 10, 10
+set ytics add ("$10^{-5}$" 1e-5, "$10^{-4}$" 1e-4, "$10^{-3}$" 1e-3, "$10^{-2}$" 1e-2, "$10^{-1}$" 1e-1, "$10^{0}$" 1, "$10^1$" 10)
+#unset mytics
+
+# default output canvas size: 12.5cm x 8.75cm
+set term lua tikz size 8,6 standalone
+
+set key top left box linetype rgbcolor"#999999" width 0.3 height 0.3 spacing 1.3
+
+# set linestyle
+set style line 1 linetype rgbcolor "#4169E1" linewidth 2 dashtype "."
+set style line 2 linetype rgbcolor "#DC143C" linewidth 2
+set style line 3 linetype rgbcolor "#32CD32" linewidth 2 dashtype "-"
+set style line 4 linetype rgbcolor "#4B0082" linewidth 2
+set style line 5 linetype rgbcolor "#DAA520" linewidth 2
+set style line 6 linetype rgbcolor "#999999" linewidth 2
+
+set pointsize 1
+
+set logscale xy
+
+plot \
+ "simpleq-compare.dat" using 1:($3<1e-2 ? 2*abs($5/2-$2)/$5 : 1/0) with lp ls 4 title "simple hc",\
+ "simpleq_soft-compare.dat" using 1:($3<1e-2 ? 2*abs($5/2-$2)/$5 : 1/0) with lp ls 1 title "simple",\
+ "mueq_soft-compare.dat" using 1:($3<1e-2 ? 2*abs($5/2-$2)/$5 : 1/0) with lp ls 3 title "med",\
+ "bigeq_soft-compare.dat" using 1:($3<1e-2 ? 2*abs($5/2-$2)/$5 : 1/0) with lp ls 5 title "big"
+