We use the density matrix renormalization group to study the quantum transitions that occur in the half-filled one-dimensional fermionic Hubbard model with onsite potential disorder. We find a transition from the gapped Mott phase with algebraic spin correlations to a gapless spin-disordered phase beyond a critical strength of the disorder $Δ_c \approx U/2$ . Both the transitions in the charge and spin sectors are shown to be coincident. We also establish the finite-size corrections to the charge gap and the spin-spin correlation length in the presence of disorder and using a finite-size-scaling analysis we obtain the zero temperature phase diagram of the various quantum phase transitions that occur in the disorder-interaction plane.We use the density matrix renormalization group to study the quantum transitions that occur in the half-filled one-dimensional fermionic Hubbard model with onsite potential disorder. We find a transition from the gapped Mott phase with algebraic spin correlations to a gapless spin-disordered phase beyond a critical strength of the disorder $Δ_c \approx U/2$. Both the transitions in the charge and spin sectors are shown to be coincident. We also establish the finite-size corrections to the charge gap and the spin-spin correlation length in the presence of disorder and using a finite-size-scaling analysis we obtain the zero temperature phase diagram of the various quantum phase transitions that occur in the disorder-interaction plane.

arXiv:cond-mat/9704027Apr 3, 19971 citation

Enhanced charge and spin currents in the one-dimensional disordered mesoscopic Hubbard ring

Rudolf A. Römer, Alexander Punnoose

We consider a one-dimensional mesoscopic Hubbard ring with and without disorder and compute charge and spin stiffness as a measure of the permanent currents. For finite disorder we identify critical disorder strength beyond which the charge currents in a system with repulsive interactions are larger than those for a free system. The spin currents in the disordered repulsive Hubbard model are enhanced only for small U, where the magnetic state of the system corresponds to a charge-density wave pinned to the impurities. For large U, the state of the system corresponds to localized isolated spins and the spin currents are found to be suppressed. For the attractive Hubbard model we find that the charge currents are always suppressed compared to the free system at all length scales.We consider a one-dimensional mesoscopic Hubbard ring with and without disorder and compute charge and spin stiffness as a measure of the permanent currents. For finite disorder we identify critical disorder strength beyond which the charge currents in a system with repulsive interactions are larger than those for a free system. The spin currents in the disordered repulsive Hubbard model are enhanced only for small U, where the magnetic state of the system corresponds to a charge-density wave pinned to the impurities. For large U, the state of the system corresponds to localized isolated spins and the spin currents are found to be suppressed. For the attractive Hubbard model we find that the charge currents are always suppressed compared to the free system at all length scales.

arXiv:cond-mat/9505110Physical review. B, Condensed matterNov 15, 199525 citations

Spin and charge fluctuations of the two-dimensional Hubbard model

Yasushi Shiina

Abstracts of the meeting of the Physical Society of Japan. Sectional meetingSep 12, 19950 citations

Disorder-induced localisation in the Mott-Hubbard model

Ričards Kristers Knipšis, Friedemann Queißer, Jesumony Jayabalan +4 more

For the Fermi-Hubbard model in the Mott insulator phase, we employ the hierarchy of correlations to study how doublon and holon quasi-particle excitations are affected by adding disorder to the system. We study two types of disorder: charge disorder, in the form of on-site potential randomness; and spin disorder, in the form of a fixed, randomly generated background spin arrangement. By analysing the quasi-particle eigen-spectra and quantifying the degree to which the corresponding eigen-states localise, we find both an energetic and spatial separation between localised and delocalised states in the charge disorder. In contrast, the spin disorder results in localised states throughout the quasi-particle bands. Finally, we repeat our calculations using strong-coupling perturbation theory, and compare the results obtained from both methods.For the Fermi-Hubbard model in the Mott insulator phase, we employ the hierarchy of correlations to study how doublon and holon quasi-particle excitations are affected by adding disorder to the system. We study two types of disorder: charge disorder, in the form of on-site potential randomness; and spin disorder, in the form of a fixed, randomly generated background spin arrangement. By analysing the quasi-particle eigen-spectra and quantifying the degree to which the corresponding eigen-states localise, we find both an energetic and spatial separation between localised and delocalised states in the charge disorder. In contrast, the spin disorder results in localised states throughout the quasi-particle bands. Finally, we repeat our calculations using strong-coupling perturbation theory, and compare the results obtained from both methods.

arXiv:2603.10238Mar 10, 20260 citations

Spin and charge fluctuations in the Hubbard model

A. Sherman

arXiv:1606.04396Journal of Magnetism and Magnetic MaterialsDec 21, 20163 citations

Δ_c \approx U/2

. Both the transitions in the charge and spin sectors are shown to be coincident. We also establish the finite-size corrections to the charge gap and the spin-spin correlation length in the presence of disorder and using a finite-size-scaling analysis we obtain the zero temperature phase diagram of the various quantum phase transitions that occur in the disorder-interaction plane.