A project of the Theoretical Chemical and Quantum Physics Group


Mr. Muhammad Ahmed, Dr. Jan Jeske, A/Prof. Jared Cole, Prof. Andrew Greentree


C. Müller, M. Marthaler, Prof. Schön: Karlsruhe Institute of Technology

S. Huelga: University of Ulm

L. Hall, L. Hollenberg: University of Melbourne

S. Devitt: NII, Tokyo, Japan

Brief Project Outline

The study of spins and their interactions (be they electron-, nuclear- or pseudo-spins) is one of the central components of quantum mechanics. In recent years, the new fields of quantum computing and quantum information processing have link the physics of spins to the fields of information theory, computing theory and cryptography. In this project, we consider the behaviour of interacting few spin systems to study entanglement, transport and measurement. This has applications to quantum computing, quantum sensing as well as the fundamental theory of quantum mechanics. Specific topics of recent interest include:

  • The interplay between decoherence and entanglement theory, the connection between entanglement quantification and entanglement sudden birth and death.
  • Hamiltonian characterisation and measurement, the extraction of system information (system calibration) from a quantum system.
  • Spin transport and the direct control of single magnons.

Geometric entanglement evolution

Evolution of the absolute geometric entanglement hierarchy within a system consisting to two atom-photon pairs, showing the inter-conversion between different classes of entanglement.
J. Cole, J. Phys. A: Math. Theor. 43 135301 (2010)

Entanglement generation

The maximum entanglement which can be generated by an interaction, governed by its position in the Weyl chamber. An arbitrary two-qubit interaction can always be expressed as a trajectory in the Weyl chamber, giving a graphical method for study the creation and destruction of entanglement during coherent evolution.

Spin-wave guiding via time-varying local magnetic potential. By varying the shape and translational speed of the potential, the spin-wave behaves in a similar manner to the light field in an optic fibre. Provided the translation of the potential is adiabatic enough, the spin-wave can be steered while staying as a coherent excitation.
Makin et al. Phys. Rev. Lett. 108 017207 (2012)

Recent Publications

J. H. Cole, Understanding entanglement sudden death through multipartite entanglement and quantum correlations, J. Phys. A: Math. Theor. 43 135301 (2010)

M. I. Makin, J. H. Cole, C. D. Hill and A. D. Greentree, Spin Guides and Spin Splitters: Waveguide Analogies in One-Dimensional Spin Chains, Phys. Rev. Lett. 108 017207 (2012)

Muhammad H. Ahmed and Andrew D. Greentree, Guided magnon transport in spin chains: Transport speed and correcting for disorder, Phys. Rev. A 91 022306 (2015)

For more information about this project, please contact Jared Cole or Andrew Greentree.