Gap Estimation by means of Hyperbolic Deformation

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dc.creatorUeda, Hiroshi
dc.creatorNakano, Hiroki
dc.creatorKusakabe, Koichi
dc.creatorNishino, Tomotoshi
dc.date2008-12-24
dc.date2009-05-15
dc.date.accessioned2026-07-07T13:14:48Z
dc.date.available2026-07-07T13:14:48Z
dc.descriptionWe present a way of numerical gap estimation applicable for one-dimensional infinite uniform quantum systems. Using the density matrix renormalization group method for a non-uniform Hamiltonian, which has deformed interaction strength of $j$-th bond proportional to $\cosh λj$, the uniform Hamiltonian is analyzed as a limit of $λ\to 0$. As a consequence of the deformation, an excited quasi-particle is weakly bounded around the center of the system, and kept away from the system boundary. Therefore, insensitivity of an estimated excitation gap of the deformed system to the boundary allows us to have the bulk excitation gap $Δ(λ)$, and shift in $Δ(λ)$ from $Δ(0)$ is nearly linear in $λ$ when $λ\ll 1$. Efficiency of this estimation is demonstrated through application to the S=1 antiferromagnetic Heisenberg chain. Combining the above estimation and another one obtained from the technique of convergence acceleration for finite-size gaps estimated by numerical diagonalizations, we conclude that the Haldane gap is in $[0.41047905,~0.41047931]$.
dc.description11 pages, 13 figures, submitted to JPSJ
dc.identifierhttps://arxiv.org/abs/0812.4513
dc.identifierhttp://arxiv.org/abs/0812.4513
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/230292
dc.subjectStatistical Mechanics
dc.subjectQuantum Physics
dc.titleGap Estimation by means of Hyperbolic Deformation
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