Publications

We observe the formation and dynamics of Jones-Roberts solitons in a superfluid of light created by a near-resonant laser beam propagating through a hot rubidium vapor. JRS were predicted more than 40 years ago, and are here observed for the first time. We study JRS dynamics, and conversion to a rarefaction pulse. Our theory of velocity correlations is in close agreement with observations.

Myrann Baker-Rasooli, Tangui Aladjidi, Nils A Krause, Ashton S Bradley, Quentin Glorieux

Physical Review Letters 134, 233401 (2025)

We explore the transition to turbulence in a quantum fluid, forced by shaking a box trap along one axis. Isotropic turbulence develops, characterized via power-law energy spectra, vortex distributions, and spatial correlations. Weak-wave turbulence at low forcing gives way to strong-vortex turbulence at high forcing, with a crossover when vortices interfere with weak-wave energy transport.

Tommy Z. Fischer, A. S. Bradley

Physical Review A 111, 2 (2025)

We develop the theory of Jones-Roberts soliton decay due to thermal transfer between the condensate and the non-condensate reservoir - particle transfer that usually drives condensate growth, and number-conserving energy transfer, which is shown to drive JRS decay. We propose experimental tests for reservoir theory using JRS that are sensitive to the phase space density.

Nils A. Krause, A. S. Bradley

Physical Review A 110, 5 (2024)

In our open systems theory of planar vortex dynamics we identify the energy-damping reservoir interaction in the stochastic projected Gross-Piteavskii theory as the origin of vortex mutual friction. Our theory bridges a large gap from dissipative phenomenolgy to a quantitative picture of mutual friction experiments.

Zain Mehdi, J. J. Hope, Stuart S. Szigeti, A. S. Bradley

Physical Review Research 5, 1 (2023)

We use optical tweezers to assemble pairs of trapped 85Rb atoms, and study the spin dynamics of the two-body system in a thermal state. The spin-2 atoms show strong pair correlation between magnetic sublevels on timescales exceeding one second, with measured relative number fluctuations 11.9 ± 0.3 dB below quantum shot noise.

Pimonpan Sompet, Stuart S. Szigeti, E. Schwartz, A. S. Bradley, Mikkel F. Andersen

Nature Communications 10, 1 (2019)

We experimentally realize vortex clusters in a planar Bose-Einstein condensate, observing first evidence of 70 year old predictions of Onsager. Clusters are robust over long time periods, maintaining the superfluid system in a high-energy state far from global equilibrium. Our experiments reveal vortex matter at negative absolute temperatures in agreement with theory.

Guillaume Gauthier, Matthew T. Reeves, Xiaoquan Yu, A. S. Bradley, Mark Baker, Thomas A. Bell, Halina Rubinsztein‐Dunlop, Matthew J. Davis, Tyler W. Neely

Science 364, 6447 1264 (2019)