2007/11/30 by K. Kudo, Kazue Kudo, T. S. Monteiro
Mathematics · Physics and Astronomy · #Classical mechanics #Cold Atom Physics and Bose-Einstein Condensates #Ferromagnetism #Geometry #Hamiltonian (control theory) #Mathematics #Phase space #Physics #Quantum #Quantum chaos and dynamical systems #Quantum mechanics #Quantum optics and atomic interactions #Statistical physics #Torus #cond-mat.other #quant-ph
paper · pdf · doi:10.1103/physreve.77.055203
published as Phys. Rev. E 77, 055203(R) (2008) · 5 pages, 4 figures
openalex publication_date 2008/05/29 · arxiv created 2008/06/07 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We investigate quantum dynamics in phase-space regions containing "shearless tori." We show that the properties of these peculiar classical phase-space structures-important to the dynamics of tokamaks-may be exploited for quantum information applications. In particular we show that shearless tori permit the nondispersive transmission of localized wave packets. The quantum many-body Hamiltonian of a Heisenberg ferromagnetic spin chain, subjected to an oscillating magnetic field, can be reduced to a classical one-body "image" dynamical system which is the well-studied Harper map. The Harper map belongs to a class of Hamiltonian systems (nontwist maps) which contain shearless tori. We show that a variant with sinusoidal time driving "driven Harper model" produces shearless tori which are especially suitable for quantum state transfer. The behavior of the concurrence is investigated as an example.