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arXiv · 1706.07486

Critical behavior of the extended Hubbard model with bond dimerization

Satoshi Ejima·Florian Lange·Fabian H. L. Essler·Holger Fehske
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Abstract

Exploiting the matrix-product-state based density-matrix renormalization group (DMRG) technique we study the one-dimensional extended ($U$-$V$) Hubbard model with explicit bond dimerization in the half-filled band sector. In particular we investigate the nature of the quantum phase transition, taking place with growing ratio $V/U$ between the symmetry-protected-topological and charge-density-wave insulating states. The (weak-coupling) critical line of continuous Ising transitions with central charge $c=1/2$ terminates at a tricritical point belonging to the universality class of the dilute Ising model with $c=7/10$. We demonstrate that our DMRG data perfectly match with (tricritical) Ising exponents, e.g., for the order parameter $β=1/8$ (1/24) and correlation length $ν=1$ (5/9). Beyond the tricritical Ising point, in the strong-coupling regime, the quantum phase transition becomes first order.

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Satoshi Ejima, Florian Lange, Fabian H. L. Essler, Holger Fehske. 2017-06-22. Critical behavior of the extended Hubbard model with bond dimerization. https://doi.org/10.1016/j.physb.2017.09.001

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