Multi-Triplon Excitations of Hubbard Ladders with Site-Dependent Potentials

We study low-lying spin-singlet excitations of two-leg Hubbard ladders with site-dependent potentials. Using general formulas of the charge disproportionation induced by the site-dependent potentials, we derive the contributions of spin degrees of freedom to the spectral functions such as the dynami...

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Bibliographic Details
Published in:Journal of the Physical Society of Japan 2024-05, Vol.93 (5), p.1
Main Authors: Maeshima, Nobuya, Hino, Ken-ichi
Format: Article
Language:English
Subjects:
Disproportionation
Excitation
Ladders
Mathematical analysis
Structure factor
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Summary:We study low-lying spin-singlet excitations of two-leg Hubbard ladders with site-dependent potentials. Using general formulas of the charge disproportionation induced by the site-dependent potentials, we derive the contributions of spin degrees of freedom to the spectral functions such as the dynamical charge structure factor N(k,ω) and the optical conductivity σγ(ω) along the γ (=x,y )-direction of the two-leg ladders. Numerical results obtained by the Lanczos diagonalization method have clarified that the multi-triplon singlet states, including two- and three-triplon excitations, can be detected by observing these quantities. Furthermore, we have found that ladders with random potentials also have non-negligible contributions of these excitations to σx(ω).
ISSN:0031-9015
1347-4073
DOI:10.7566/JPSJ.93.054707