Spin Glass Server

This is a continuation of the Spin Glass service originally provided by the former COPhy research group of Frauke Liers and the former research group of Michael Jünger at the University of Cologne. In consent with these and the further contributors Petra Mutzel, Giovanni Rinaldi, Angelika Wiegele, Martin Diehl, and Gerhard Reinelt, the service has been relaunched at the University of Bonn by Sven Mallach. We also gratefully acknowledge the work of Thomas Lange, Marc Egger, and Mark Sprenger.

This service computes exact ground states of Ising spin glasses and partition functions of Potts glasses with many states.
The following geometries are supported:
  • Ising spin glass on a:
    • two-dimensional planar quadratic lattice (free boundary in at least one direction)
    • complete graph (Sherrington-Kirkpatrick (SK) spin-glass model). For the SK model, we use the Biq Mac algorithm.
  • Dominant contribution in partition function for Potts glasses with many states (on all graph types).

Further, for the geometries
  • two-dimensional quadratic lattice on a torus (periodic boundaries in both directions)
  • three-dimensional lattice (periodic boundaries in all directions)
as well as the two-dimensional planar case mentioned above, please use the more recently developed McGroundstate. In this case, please take account of the slightly different instance format.

Please note that this service comes without any guarantee or warranty.
By submitting an instance, you confirm that you use this service solely for non-profit scientific or private intent.

The input format is described below, results are returned by email.

Submit your file(s) ...
(each instance has to be a text file; files can be bundled into an archive; supported archive-formats are tar, tar.gz and zip)
file name
type Ising spin glass
Potts infinite
email address

The input format is as follows:

name: the name of the instance
spin_i1   spin_j1   coupling between i1 and j1
spin_i2   spin_j2   coupling between i2 and j2

If the instance should be named like the filename, simply skip the line name: ... in the file.
Lattices with uniformly distributed ±J couplings need to be scaled to ±1 couplings.

See an example of the input format together with the corresponding results from the server here.
For lattice models, spins are numbered sequentially layer by layer starting with index 1.
For example, a two-dimensional 3x3 spin glass is numbered as follows:

     |       |       |
     |       |       |
     |       |       |
     |       |       |

For the non-lattice models such as the Sherrington-Kirkpatrick (SK) model, the order of the spins is arbitrary.

A more general instance generator can be downloaded here.