Non-linear dynamics, entanglement and the quantum-classical crossover of two coupled SQUID rings

Abstract

We explore the quantum-classical crossover of two coupled, identical, superconducting quantum interference device (SQUID) rings. We note that the motivation for this work is based on a study of a similar system comprising two coupled Duffing oscillators. In that work we showed that the entanglement characteristics of chaotic and periodic (entrained) solutions differed significantly and that in the classical limit entanglement was preserved only in the chaotic-like solutions. However, Duffing oscillators are a highly idealised toy model. Motivated by a wish to explore more experimentally realisable systems we now extend our work to an analysis of two coupled SQUID rings. We observe some differences in behaviour between the system that is based on SQUID rings rather than on Duffing oscillators. However, we show that the two systems share a common feature. That is, even when the SQUID ring's trajectories appear to follow (semi) classical orbits entanglement persists.

9 pages, 4 figures. Published as part of the proceedings of the 32nd International Workshop on Condensed Matter Theories (CMT32) Loughborough University, 2008 (invited paper)

References in corpus (10)

• Concentrating Partial Entanglement by Local Operations
• Decoherence, Chaos, and the Correspondence Principle
• Continuous Quantum Measurement and the Emergence of Classical Chaos
• Quantum state diffusion, localization and computation
• Quantum chaos in open systems: a quantum state diffusion analysis
• Continuous Quantum Measurement and the Quantum to Classical Transition
• The transition to classical chaos in a coupled quantum system through continuous measurement
• From quantum trajectories to classical orbits
• Semiclassics of the Chaotic Quantum-Classical Transition
• Recovery of classical chaotic-like behaviour in a quantum three-body problem