Density-matrix renormalization study of the Hubbard model on a Bethe lattice
| dc.creator | Lepetit, Marie-Bernadette | |
| dc.creator | Cousy, Maixent | |
| dc.creator | Pastor, G. M. | |
| dc.date | 1998-01-22 | |
| dc.date | 1998-09-10 | |
| dc.date.accessioned | 2026-07-25T23:39:25Z | |
| dc.description | The half-filled Hubbard model on the Bethe lattice with coordination number $z=3$ is studied using the density-matrix renormalization group (DMRG) method. Ground-state properties such as the energy $E$, average local magnetization $<\hat S_z>$, its fluctuations $<\hat S_z^2 > - < \hat S_z>^2$ and various spin correlation functions $<\hat S_z(i) \hat S_z(j) > - < S_z(i)> < S_z(j)>$ are determined as a function of the Coulomb interaction strength $U/t$. The calculated local magnetic moments $<\hat S_z(i)>$ increase monotonically with increasing Coulomb repulsion $U/t$ forming an antiferromagnetic spin-density-wave state which matches the two sublattices of the bipartite Bethe lattice. At large $U/t$, $<\hat S_z(i)>$ is strongly reduced with respect to the saturation value 1/2 due to exchange fluctuations between nearest neighbors (NN) spins ($|< S_z(i)>|\simeq 0.35$ for $U/t\to +\infty$). $<S_z(i)^2> - < S_z(i)>^2$ shows a maximum for $U/t=2.4$--2.9 which results from the interplay between the usual increase of $<S_z(i)^2>$ with increasing $U/t$ and the formation of important permanent moments $<S_z(i)>$ at large $U/t$. NN sites show antiferromagnetic spin correlations which increase with increasing Coulomb repulsion. In contrast next NN sites are very weakly correlated over the whole range of $U/t$. The accuracy of the DMRG results is discussed by comparison with tight-binding exact results, independent DMRG calculations for the Heisenberg model and simple first-order perturbation estimates. | |
| dc.description | 12 pages - 9 postscript figures | |
| dc.identifier | https://arxiv.org/abs/cond-mat/9801228 | |
| dc.identifier | http://arxiv.org/abs/cond-mat/9801228 | |
| dc.identifier.uri | https://dspace.dare.co.zw/handle/123456789/100350 | |
| dc.subject | Strongly Correlated Electrons | |
| dc.title | Density-matrix renormalization study of the Hubbard model on a Bethe lattice | |
| dc.type | text |