Quantum Nonlinear Switching Model
| dc.creator | Garanin, D. A. | |
| dc.creator | Schilling, R. | |
| dc.date | 2003-07-15 | |
| dc.date.accessioned | 2026-07-07T02:52:22Z | |
| dc.date.available | 2026-07-07T02:52:22Z | |
| dc.description | We present a method, the dynamical cumulant expansion, that allows to calculate quantum corrections for time-dependent quantities of interacting spin systems or single spins with anisotropy. This method is applied to the quantum-spin model \hat{H} = -H_z(t)S_z + V(\bf{S}) with H_z(\pm\infty) = \pm\infty and Ψ(-\infty)=|-S> we study the quantity P(t)=(1-<S_z>_t/S)/2. The case V(\bf{S})=-H_x S_x corresponds to the standard Landau-Zener-Stueckelberg model of tunneling at avoided-level crossing for N=2S independent particles mapped onto a single-spin-S problem, P(t) being the staying probability. Here the solution does not depend on S and follows, e.g., from the classical Landau-Lifshitz equation. A term -DS_z^2 accounts for particles' interaction and it makes the model nonlinear and essentially quantum mechanical. The 1/S corrections obtained with our method are in a good accord with a full quantum-mechanical solution if the classical motion is regular, as for D>0. | |
| dc.description | 4 Phys. Rev. pages 2 Figs | |
| dc.identifier | https://arxiv.org/abs/cond-mat/0307371 | |
| dc.identifier | http://arxiv.org/abs/cond-mat/0307371 | |
| dc.identifier | Phys. Rev. B 69, 104412 (2004) | |
| dc.identifier | doi:10.1103/PhysRevB.69.104412 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/21817 | |
| dc.subject | Statistical Mechanics | |
| dc.title | Quantum Nonlinear Switching Model | |
| dc.type | text |