Welcome to the UQ Bose-Einstein Condensation laboratory

Located in warm and subtropical Brisbane, we explore the coldest matter in the universe, Bose-Einstein condensates (BEC). We are interested in the applications of ultracold atomic systems. These include problems of fundamental physics interest, such as quantum turbulence, quantum thermodynamics, and exotic spin defects, but also includes application oriented research, such as quantum sensing and atomtronics. We operate two different apparatuses in our lab that provide complimentary capabilities:

  • Scalar apparatus: This machine is built around a small glass vacuum cell which allows high-resolution patterning of arbitrary time-dependent potentials and imaging of resulting atom configurations. In this apparatus we are currently pursuing experiments in quantum turbulence, quantum thermodynamics and sensing. These experiments are conducted with ⁸⁷Rb, but we aim to implement a second species, ⁴¹K, in the near future.

  • Spinor apparatus: This BEC apparatus utilises three different spin substates of ⁸⁷Rb. Through projecting arbitrary potentials on the atoms, we can deterministically create spin defects on demand. The high degree of control allows us to accurately study spin interactions, as well as quantum turbulence of mixed spin systems and quantum sensing.

We are looking for undergraduate, honours, and PhD students! Please browse our available projects for more information.

Publications

Featured
Our paper exploring a universal drag law in superfluids is available on the arXiv!
Our paper exploring a universal drag law in superfluids is available on the arXiv!

Our paper ‘Emergent Universal Drag Law in a Model of Superflow’ is on the arXiv now, find it here: https://arxiv.org/abs/2406.14049!

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Our paper on exploring the limits of phonon interferometry as rotation sensors has been published in SciPost Physics!
Our paper on exploring the limits of phonon interferometry as rotation sensors has been published in SciPost Physics!

In this work, we study the viability of rotation sensing using phonon interferometers in Bose-Einstein condensates.

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Official opening of the new UQ Bose-Einstein Condensate Laboratory and the Superconducting Quantum Devices lab
Official opening of the new UQ Bose-Einstein Condensate Laboratory and the Superconducting Quantum Devices lab
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Our paper on creating persistent current using machine learning is available on the arXiv!
Our paper on creating persistent current using machine learning is available on the arXiv!
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News

Featured
Optimizing persistent currents in a ring-shaped Bose-Einstein condensate using machine learning
Optimizing persistent currents in a ring-shaped Bose-Einstein condensate using machine learning

We demonstrate a method for generating persistent currents in Bose-Einstein condensates by using a Gaussian process learner to experimentally control the stirring of the superfluid. The learner optimizes four different outcomes of the stirring process: (O.I) targeting and (O.II) maximization of the persistent current winding number and (O.III) targeting and (O.IV) maximization with time constraints. The learner optimizations are determined based on the achieved winding number and the number of spurious vortices introduced by stirring. We find that the learner is successful in optimizing the stirring protocols, although the optimal stirring profiles vary significantly depending strongly on the choice of cost function and scenario. These results suggest that stirring is robust and persistent currents can be reliably generated through a variety of stirring approaches.

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Viability of rotation sensing using phonon interferometry in Bose-Einstein condensates
Viability of rotation sensing using phonon interferometry in Bose-Einstein condensates

Charles W. Woffinden, Andrew J. Groszek, Guillaume Gauthier, Bradley J. Mommers, Michael. W. J. Bromley, Simon A. Haine, Halina Rubinsztein-Dunlop, Matthew J. Davis, Tyler W. Neely, Mark Baker, SciPost Phys. 15, 128 (2023) - Published 2 October 2023

In this work, we cool down rubidium atoms to close to absolute zero to form a Bose Einstein Condensate. We form this condensate into a ring, then create sound waves travelling around the circumference of the ring. These sound waves (or phonons) create a standing wave in the density of the condensate, with high- and low-density points around the ring which act as markers. Due to the superfluid nature of the condensate, these markers stay in the same location of the ring and don’t rotate, even if the lab frame of reference is rotating (e.g. due to Earth’s rotation). This means that these markers act as an absolute frame of reference - like the north-seeking pole on a compass and so could potentially be used for navigation in situations where satellite navigation is not available e.g. under water.

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Scaling dynamics of the ultracold Bose gas
Scaling dynamics of the ultracold Bose gas

Ashton S. Bradley, Jordan Clarke, Tyler W. Neely, and Brian P. Anderson, Phys. Rev. A 106, 053316 – Published 18 November 2022

The large-scale expansion dynamics of quantum gases is a central tool for ultracold gas experiments and poses a significant challenge for theory. In this work we provide an exact reformulation of the Gross-Pitaevskii equation for the ultracold Bose gas in a coordinate frame that adaptively scales with the system size during evolution, enabling simulations of long evolution times during expansion or similar large-scale manipulation.

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