868 citations · 1.2k across the 14 of their papers we have counts for
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Dirac Fermions on a Two-Dimensional Lattice and the Intermediate Metallic Phase
K. Ziegler
Consequences of different discretizations of the two-dimensional Dirac operator on low energy properties (e.g., the number of nodes) and their relations to gauge properties are dis…
Level statistics and localization in a 2D quantum percolation problem
M. Letz, K. Ziegler
A two dimensional model for quantum percolation with variable tunneling range is studied. For this purpose the Lifshitz model is considered where the disorder enters the Hamiltonia…
Functional Integration in Bose Systems with Hard-Core Interaction
K. Ziegler
A grand canonical ensemble of interacting bosons is considered. The zero temperature phase diagram is evaluated from the mean-field approximation of the functional integral. Three…
The Energy-Energy Correlation Function of the Random Bond Ising Model in Two Dimensions
K. Ziegler
The energy-energy correlation function of the two-dimensional Ising model with weakly fluctuating random bonds is evaluated in the large scale limit. Two correlation lengths exist…
Stability of Insulating Phases in the Hubbard Model: a Cluster Expansion
K. Ziegler
The stability of the insulating regime of the Hubbard model on a -dimensional lattice, which is characterized by an exponential decay of the Green's functions, is investigated i…