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cond-mat.str-el1999
Excitation Spectrum for Quantum Spin Systems with Ladder, Plaquette and Mixed-Spin Structures
Akihisa Koga, Norio Kawakami
By using the series expansion techniques, we study the excitation spectrum for the two-dimensional quantum spin systems with ladder, plaquette and mixed-spin structures. We calcula…
cond-mat.str-el1999
Mixed-spin cluster expansion for a quasi-one-dimensional Haldane system
Akihisa Koga, Norio Kawakami
We present a novel mixed-spin cluster expansion method for a quasi-one-dimensional Haldane system with bond alternation. By mapping the s=1 antiferromagnetic spin model on square a…