Topological Physics and Novel Devices with Transmission Line Networks PHY-12-Whittaker

Details

This project looks at a new physical system for studying topological physics, using networks of radio frequency transmission lines made from coaxial cables. The underpinning theory is our discovery of a mapping from these networks to tight binding Hamiltonians of solid state physics - we can, for example, make an analogue of a graphene lattice, where the radio frequency transmission mimics the behaviour of electrons in real graphene. An important property of these Hamiltonians is that they have a symmetry, known as chiral symmetry, which leads to a non-trivial topological classification, with different structures having different topologies. As a consequence, we can use our networks to investigate topological physics concepts, such as topologically protected states, whose energies remain completely unchanged when we add disorder to a structure. In the case of graphene, we are currently looking at how making structures with different topologies, by changing the way that we connect the edges, as a tube, torus or Klein bottle geometry.

In this project, we will investigate other topologically interesting lattices, such as the Kagome lattice, and making structures with different symmetries, such as particle-hole symmetry, which have different sorts of topological properties. We will also look at hybrid structures, where we introduce some electronic components at the junctions between cables, to provide increased functionality such as breaking time-reversal symmetry and adding gain and loss. An important part of the project will be to extend the frequencies at which we work, currently ~100MHz, to the GHz range. At these frequencies, it is not possible to use coaxial cables, so we seek to develop stripline structures with similar behaviour. The aim is to design novel devices for use at high frequencies, where traditional discrete electronic components do not work well.

The project has a strong theoretical component. However, the unique feature of our networks is that we can perform experimental studies of topological physics, so ideally we would like to recruit a student with interest in both aspects.

A link to the application form can be found here https://www.sheffield.ac.uk/arpform/login.app?code=EPSRC

Interested candidates are strongly encouraged to contact the project supervisors to discuss your interest in and suitability for the project prior to submitting your application.

Please refer to the EPSRC DTP webpage for detailed information about the EPSRC DTP and how to apply.