arXiv subjects
Publications and source records attributed to Juergen Schnack.
We present up to date investigations of the antiferromagnetic Heisenberg icosidodecahedron by means of the Density Matrix Renormalization Group method. We compare our results with modern Correlator Product State as well as Lanczos calculations.
We give two examples where symmetric polynomials play an important role in physics: First, the partition functions of ideal quantum gases are closely related to certain symmetric polynomials, and a part of the corresponding theory has a thermodynamical interpretation. Further, the same symmetric polynomials also occur in Berezin's theory of quantization of phase spaces with constant curvature.
We apply the density-matrix renormalization group technique to magnetic molecules in order to evaluate the low-lying energy spectrum. In particular, we investigate the giant Keplerate molecule Mo72Fe30 where 30 Fe3+ ions (spins 5/2) occupy the sites of an icosidodecahedron and interact via nearest-neighbor antiferromagnetic Heisenberg exchange. The aim of our investigation is to verify the applicability and feasibility of DMRG calculations for complex magnetic molecules. To this end we first use a fictitious molecule with the same structure as Mo72Fe30 but with spins 1/2 as a test system. Here we investigate the accuracy of our DMRG implementation in comparison to numerically exact results. Then we apply the algorithm to Mo72Fe30 and calculate an approximation of the lowest energy levels in the subspaces of total magnetic quantum number. The results prove the existence of a lowest rotational band, which was predicted recently.