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The ground state of the two-leg Hubbard ladder: a density--matrix renormalization group study

R. M. Noack·S. R. White·D. J. Scalapino
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Abstract

We present density-matrix renormalization group results for the ground state properties of two-leg Hubbard ladders. The half-filled Hubbard ladder is an insulating spin-gapped system, exhibiting a crossover from a spin-liquid to a band-insulator as a function of the interchain hopping matrix element. When the system is doped, there is a parameter range in which the spin gap remains. In this phase, the doped holes form singlet pairs and the pair-field and the "$4 k_F$" density correlations associated with pair density fluctuations decay as power laws, while the "$2 k_F$" charge density wave correlations decay exponentially. We discuss the behavior of the exponents of the pairing and density correlations within this spin gapped phase. Additional one-band Luttinger liquid phases which occur in the large interband hopping regime are also discussed.

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R. M. Noack, S. R. White, D. J. Scalapino. 1996-01-14. The ground state of the two-leg Hubbard ladder: a density--matrix renormalization group study. https://doi.org/10.1016/s0921-4534(96)00515-1

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