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arXiv:0706.1424 · Physical Review Letters

Theory of Antibound States in Partially Filled Narrow Band Systems

G. Seibold, Federico Becca, J. Lorenzana

Published Jan 11, 2008• 32 citations
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Abstract

We present a theory of the dynamical two-particle response function in the Hubbard model based on the time-dependent Gutzwiller approximation. The results are in excellent agreement with exact diagonalization on small clusters and are reliable even for high densities, where the usual ladder approximation breaks down. We apply the theory to the computation of antibound states relevant for Auger spectroscopy and cold atom physics.

DOI
10.1103/physrevlett.100.016405

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We present a theory of the dynamical two-particle response function in the Hubbard model based on the time-dependent Gutzwiller approximation. The results are in excellent agreement with exact diagonalization on small clusters and are reliable even for high densities, where the usual ladder approximation breaks down. We apply the theory to the computation of antibound states relevant for Auger spectroscopy and cold atom physics.
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Based on the variational Gutzwiller theory, we present a method for the computation of response functions for multiband Hubbard models with general local Coulomb interactions. The improvement over the conventional random-phase approximation is exemplified for an infinite-dimensional two-band Hubbard model where the incorporation of the local multiplet structure leads to a much larger sensitivity of ferromagnetism on the Hund coupling. Our method can be implemented into local-density approximation and Gutzwiller schemes and will therefore be an important tool for the computation of response functions for strongly correlated materials.
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