Dear Dirk,

From: Dirk Schuricht schuricht@thphys.ox.ac.uk Date: Wed, 6 Jun 2007 14:29:10 +0100

how can I specify an Hamitonian with long-range interactions in the .xml files? For example, I would like to implement the Haldane- Shastry model, i.e. an S=1/2 antiferromagnetic Heisenberg chain whose interaction strength falls off as 1/r^2?

Currently, there is no way to define long-range models in a sophisticated way. You have to define explicitly all the sites and all the bonds with different types for different length (see e.g. "4-site mixed" in lattices.xml), though it would be quite error-prone.

Best, Synge