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Excited states of quantum many-body interacting systems: A variational coupled-cluster description

Y. Xian
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Abstract

We extend recently proposed variational coupled-cluster method to describe excitation states of quantum many-body interacting systems. We discuss, in general terms, both quasiparticle excitations and quasiparticle-density-wave excitations (collective modes). In application to quantum antiferromagnets, we reproduce the well-known spin-wave excitations, i.e. quasiparticle magnons of spin $\pm 1$. In addition, we obtain new, spin-zero magnon-density-wave excitations which has been missing in Anserson's spin-wave theory. Implications of these new collective modes are discussed.

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Y. Xian. 2007-01-19. Excited states of quantum many-body interacting systems: A variational coupled-cluster description. https://doi.org/10.1088/0953-8984%2F19%2F21%2F216221

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