Compute radius of compactification

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Read these remarks before use !

Magnetization <M> (between -1 and 1):  
     XXZ-anisotropy Delta:

Accepted input are floating point numbers or ratios thereof (i.e. rational numbers).

Remarks:

The notations used by this program are explained in [1] which we also refer to for additional explanations of the algorithms used by this program.
The response may take a while depending on the amount of computation involved in processing your input (a response can take up to about half a minute). So, be a bit patient !
We have done our best to ensure correctness of the information to which this page provides access. However, no responsability (in legal terms) can be taken for any harm caused by its use. We reserve the right to (temporarily) disable access, although we hope that circumstances will not arise in which this may be necessary.
If the information provided by this page should be useful for you, we would be grateful if you could acknowledge this by including a reference to [1] in publications where such information enters.
In case of problems or if this WWW interface turns out to be too cumbersome for obtaining a larger amount of data contact . (I'm sorry that I can't just provide the source of the program, but unfortunately a math package is used which is not public domain).

Acknowledgments:
We would like to thank G. Albertini, F.C. Alcaraz, F.H.L. Eßler, M. Oshikawa, K. Totsuka and B. Wehefritz for very helpful discussions about the equations on which this program is based.

This figure should give you a rough idea about some of the issues implemented in this program (see also [2,3] for similar pictures). This program aims at the coloured region in this figure (including the boundaries).

D.C. Cabra, A. Honecker, P. Pujol, Magnetization Plateaux in N-Leg Spin Ladders, Phys. Rev. B58 (1998) 6241-6257
J.D. Johnson, B.M. McCoy, Low-Temperature Thermodynamics of the |Delta| >= 1 Heisenberg-Ising Ring, Phys Rev. A6 (1972) 1613-1626
F.C. Alcaraz, A.L. Malvezzi, Critical and Off-Critical Properties of the XXZ Chain in External Homogeneous and Staggered Magnetic Fields, J. Phys. A: Math. Gen. 28 (1995) 1521-1534

Original version: February, 26th, 1998
Last updated: March, 24th, 2005

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