# I did this after generating data for 4 different momenta using the fortran code given,
# with qqx=qqy, named accordingly and y-origin displaced,
# with t=1 and delta=0.5.
unset ytics
set xrange [0 to 1.5]
set yrange [0 to 40]
set xlabel "E[eV]"
set label "Egap" at 0.95,-0.5
set key off
set terminal postscript "helvitica" 24
set output "Ladder.ps"
plot 'Ladder0.25.dat' u 1:2 w l 1, 'Ladder0.50.dat' u 1:2 w l 1, 'Ladder0.75.dat' u 1:2 w l 1, 'Ladder1.00.dat' u 1:2 w l 1
rep