In recent decades it has become possible to cool gases of neutral atoms down to the lowest-known temperatures in the universe, only a few billionths of a degree above absolute zero. At such extreme conditions, new phases can be found, such as Bose-Einstein condensates and superfluids that display remarkable properties such as the ability to transport particles with zero energy dissipation. While individual atoms are relatively well understood, when corralled in a many-body setting they display rich collective behaviours that enable precision tests of theoretical models that may help explain phenomena observed in complex materials such as superconductors and topological insulators. Cold atoms may therefore play a significant role in future developments in quantum materials and technologies.
In the ultracold Fermi gas experimental group, we use gases of Li-6 atoms to investigate strongly correlated fermions in the crossover from a Bardeen-Cooper-Schrieffer (BCS) superfluid of Cooper pairs to a Bose-Einstein condensate (BEC) of molecules. The ability to control the interparticle interactions using Feshbach resonances, as well as the confining potential and dimensionality of the system, enable us to characterise these Fermi systems with unprecedented accuracy. We have developed several innovations to probe these systems as highlighted in our specific areas of interest.
Our research projects
Our recent work has focussed on measuring excitations and universal properties using Bragg spectroscopy¹⁻³ and Fermi gases confined to move in two spatial dimensions⁴⁻⁵. As part of the ARC Centre of Excellence for Future Low-Energy Electronic Technologies (FLEET) we are testing new paradigms for dissipationless transport in topological and non-equilibrium quantum matter synthesised from ultracold atoms.
¹High-Frequency Sound in a Unitary Fermi Gas, C. C. N. Kuhn, S. Hoinka, I. Herrera, P. Dyke, J. J. Kinnunen, G. M. Bruun, and C. J. Vale, Phys. Rev. Lett. 124, 150401 (2020).
²Contact and Sum Rules in a Near-Uniform Fermi Gas at Unitarity, C. Carcy, S. Hoinka, M. G. Lingham, P. Dyke, C. C. N. Kuhn, H. Hu, and C. J. Vale, Phys. Rev. Lett. 122, 203401 (2019).
³Goldstone Mode and Pair-Breaking Excitations in Atomic Fermi Superfluids, S. Hoinka, P. Dyke, M. G. Lingham, J. J. Kinnunen, G. M. Bruun, and C. J. Vale, Nature Phys. 13, 943 (2017).
⁴Quantum Anomaly and 2D-3D Crossover in Strongly Interacting Fermi Gases, T. Peppler, P. Dyke, M. Zamorano, I. Herrera, S. Hoinka, and C. J. Vale, Phys. Rev. Lett. 121, 120402 (2018).
⁵Thermodynamics of an attractive 2D Fermi gas, K. Fenech, P. Dyke, T. Peppler, M. G. Lingham, S. Hoinka, H. Hu, and C. J. Vale, Phys. Rev. Lett. 116, 045302 (2016).