## Spin physics, spin-chains, quantum magnonics and entanglement theory

A project of the Theoretical Chemical and Quantum Physics Group

## Team

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

## Collaborators

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.

## 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.