Events

Date: 26 November 2025   Time: 15:00 - 16:00

Location: GO Jones 610

There will be two talks from CCMP PhD students - Oliver Trayler and Joseph Owen. Abstracts below:

Oliver Trayler
Observing entanglement in isolated spin states for aid in observation of QSLs
Quantum Spin Liquids (QSLs) are a state of matter with a fluctuating ground state, and without long-range magnetic order. QSLs are expected to occur in certain frustrated magnetic systems, and confirmation of their existence is usually sought using neutron scattering. Experimental evidence for QSLs is difficult to definitively obtain, because the signatures of QSLs can be confused with those caused by structural and chemical disorder. One way around this is to demonstrate the use of experimental measures which directly probe the presence of long range entanglement.
In this talk I will focus on basic models of an isolated spin pair, triangle and square where I have started setting benchmarks for entanglement measures, the goal of these being application to QSLs. I will be going over calculations of the susceptibility (used as an entanglement measure) and structure factor, with current progress towards calculating the Quantum Fisher Information from the structure factor which is a commonly used entanglement measure.

Joseph Owen
Graphene-based single electron transistors
Single-electron transistors (SETs) have received interest, not only in the context of quantum information processing, but additionally as tools for quantum sensing and for probing electron transport and electron-phonon coupling at the quantum/classical interface. The unique band structure of graphene and its nature as a 2d material allows for control over key device parameters, such as the addition energy, tunnel barrier height, and density of states. Graphene also provides a convenient platform for coupling to individual molecules, thanks to its flat geometry and chemical stability.
As a group we are interested in graphene SETs and hybrid graphene-molecule junctions for quantum sensing and spectroscopy. The former offers relatively straightforward fabrication and robustness of operation, while the latter opens up possibilities to investigate the quantum dynamics of individual molecules in out-of-equilibrium states. I will discuss the principles of single-electron transport, and the key challenges associated with fabricating and measuring such sensitive devices in a reproducible manner. I will present recent results and discuss some directions for future research.