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cond-mat.str-el2008
Diagrammatic approximations for the 2d quantum antiferromagnet: exact projection of auxiliary fermions
Jan Brinckmann, Peter Woelfle
We present diagrammatic approximations to the spin dynamics of the 2d Heisenberg antiferromagnet for all temperatures, employing an auxiliary-fermion representation. The projection…
cond-mat.str-el2004
Auxiliary-Fermion Approach to Critical Fluctuations in the 2D Quantum AF Heisenberg Model
Jan Brinckmann, Peter Woelfle
The nearest-neighbor quantum-antiferromagnetic (AF) Heisenberg model for spin 1/2 on a two-dimensional square lattice is studied in the auxiliary-fermion representation. Expressing…
cond-mat.str-el2001
Energy Scales in the Local Magnetic Excitation Spectrum of YBCO
Jan Brinckmann, Patrick A. Lee
The wave-vector integrated dynamical spin susceptibility chi_{2D}(omega) of YBCO cuprates is considered. chi_{2D} is calculated in the superconducting state from a renormalized mea…