Control field on an open chain of L = 400 places, J = 1.0, x1 = 100, g1 = g2 = 1, N_f = 1
Delta/J = 2.02: phi = |empty> (overlap 1.000000000000000), gap = 0.0201; xi = 1/arccosh(Delta/2J) = 7.07695; fitted decay length = 7.07695; max |M2/(4.14) - 1| over d = 1..160 = 5.7e-13
   d  :         1          5         10         20         40         80
   M2 : -6.12e+00  -3.48e+00  -1.72e+00  -4.18e-01  -2.48e-02  -8.69e-05
   d^6 |M2| : 6.12e+00  5.44e+04  1.72e+06  2.67e+07  1.01e+08  2.28e+07
Delta/J = 2.1: phi = |empty> (overlap 1.000000000000000), gap = 0.1001; xi = 1/arccosh(Delta/2J) = 3.17536; fitted decay length = 3.17536; max |M2/(4.14) - 1| over d = 1..88 = 2.2e-15
   d  :         1          5         10         20         40         80
   M2 : -2.28e+00  -6.47e-01  -1.34e-01  -5.74e-03  -1.06e-05  -3.57e-11
   d^6 |M2| : 2.28e+00  1.01e+04  1.34e+05  3.68e+05  4.33e+04  9.37e+00
Delta/J = 2.5: phi = |empty> (overlap 1.000000000000000), gap = 0.5001; xi = 1/arccosh(Delta/2J) = 1.44270; fitted decay length = 1.44270; max |M2/(4.14) - 1| over d = 1..40 = 2.4e-15
   d  :         1          5         10         20         40         80
   M2 : -6.67e-01  -4.17e-02  -1.30e-03  -1.27e-06  -1.21e-12  -1.10e-24
   d^6 |M2| : 6.67e-01  6.51e+02  1.30e+03  8.14e+01  4.97e-03  2.89e-13
Delta/J = 3.0: phi = |empty> (overlap 1.000000000000000), gap = 1.0001; xi = 1/arccosh(Delta/2J) = 1.03904; fitted decay length = 1.03904; max |M2/(4.14) - 1| over d = 1..29 = 2.9e-15
   d  :         1          5         10         20         40         80
   M2 : -3.42e-01  -7.27e-03  -5.91e-05  -3.91e-09  -1.71e-17  -3.26e-34
   d^6 |M2| : 3.42e-01  1.14e+02  5.91e+01  2.50e-01  7.00e-08  8.55e-23