Quantum transport and spin dynamics on shearless tori

Abstract

We investigate for 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 non-dispersive transmission of localized wavepackets. 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 (non-twist 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.

5 pages, 4 figures

References in corpus (13)

• Entanglement of Formation of an Arbitrary State of Two Qubits
• Quantum Communication Through an Unmodulated Spin Chain
• On general relation between quantum ergodicity and fidelity of quantum dynamics
• Time evolution of a quantum many-body system: transition from integrability to ergodicity in thermodynamic limit
• Generic Quantum Ratchet Accelerator with Full Classical Chaos
• Entanglement and dynamics of spin-chains in periodically-pulsed magnetic fields: accelerator modes
• The Breakup Condition of Shearless KAM Curves in the Quadratic Map
• Indicators of Reconnection Processes and Transition to Global Chaos in Nontwist Maps
• General Approach to the Quantum Kicked Particle in a Magnetic Field: Quantum-Antiresonance Transition
• Entanglement-screening by nonlinear resonances
• A map from 1d Quantum Field Theory to Quantum Chaos on a 2d Torus
• Nonlinearity effects in the kicked oscillator
• Quantized Orbits and Resonant Transport

Cited by in corpus (3)

• Aspects of Floquet Bands and Topological Phase Transitions in a Continuously Driven Superlattice
• Study of wave chaos in a randomly-inhomogeneous oceanic acoustic waveguide: spectral analysis of the finite-range evolution operator
• Doubly excited ferromagnetic spin-chain as a pair of coupled kicked rotors