Ollie Hart
Ollie Hart
Member of Corpus Christi College
PhD student in Dr Castelnovo's group
Office: 540 Mott Bld
Phone: +44(0)1223 3 37354
Email: ocmh2 @ cam.ac.uk
TCM Group, Cavendish Laboratory
19 JJ Thomson Avenue,
Cambridge, CB3 0HE UK.
Research
My research is broadly concerned with the study of quantum spin liquids at nonzero temperatures. In particular, I have worked on:
- Characterising the extent to which the state of a given system is “quantum.” Utilising entanglement measures from the quantum information community, such as the logarithmic negativity, we are able to partially answer this question by quantifying the quantum correlations present in the system.
- Identifying possible experimental signatures associated with the loss of quantum coherence on quasiparticle dynamics in quantum spin liquids. At finite temperature, a finite density of defects is excited throughout the lattice. Since the quasiparticles obey nontrivial braiding statistics, it is interesting to ask what effect these defects have on quasiparticle propagation, and in turn on the dynamical structure factor.
In Plain English
A quantum spin liquid is a material in which the constituent degrees of freedom, spins, do not order even at the absolute zero of temperature. The behaviour of this liquid-like state is dominated by strong fluctuations. This phenomenon naturally arises in two dimensions as a result of geometric frustration (e.g., in frustrated magnets).
Real experiments on quantum spin liquids always take place at some temperature above absolute zero. The main goal of my research is to understand the change from “quantum” to “classical” behaviour as temperature is increased in these systems. We would like to understand through the use of simple models the effect that this has on experiments, such as neutron scattering.
Featured Publications
- Long-range Coulomb interactions and non-hydrodynamic behaviour in thermal quenches in spin ice Phys. Rev. B 100 184411 (2019)
- Steady-state superconductivity in electronic materials with repulsive interactions Phys. Rev. B 100 060508 (2019)
- Entanglement negativity and sudden death in the toric code at finite temperature Phys. Rev. B 97 144410 (2018)
- Coherent propagation of quasiparticles in topological spin liquids at finite temperature