Publications

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Open access papers are available on arXiv.

Group highlights

Observation of Jones-Roberts solitons in a paraxial quantum fluid of light

We investigate 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. We excite a vortex-antivortex dipole and observe its transition to a rarefaction pulse and back. Motion according to ray optics, and localised velocity correlations are consistent with JRS.

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

Physical Review Letters , (2025)

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Regimes of steady-state turbulence in a quantum fluid

We simulate the Gross-Pitaevskii equation to model the development of turbulence in a quantum fluid confined by a cuboid box potential and forced by shaking along one axis. We observe the development of isotropic turbulence from anisotropic forcing for a broad range of forcing amplitudes and characterize the states through their Fourier spectra, vortex distributions, and spatial correlations.

Tommy Z. Fischer, A. S. Bradley

Physical review A 111, 2 (2025)

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Thermal decay of planar Jones-Roberts solitons

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)

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Mutual friction and diffusion of two-dimensional quantum vortices

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)

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Thermally robust spin correlations between two 85Rb atoms in an optical microtrap

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)

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Giant vortex clusters in a two-dimensional quantum fluid

We experimentally realize vortex clusters in a planar Bose-Einstein condensate. We demonstrate that the clusters persist for 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.

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)

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Full List of publications

  1. Observation of Jones-Roberts solitons in a paraxial quantum fluid of light
    Myrann Baker-Rasooli, Tangui Aladjidi, Nils A Krause, Ashton S Bradley, Quentin Glorieux
    Physical Review Letters , (2025)
    Open access:
  2. Regimes of steady-state turbulence in a quantum fluid
    Tommy Z. Fischer, A. S. Bradley
    Physical review A 111, 2 (2025)
    Open access:
  3. Thermal decay of planar Jones-Roberts solitons
    Nils A. Krause, A. S. Bradley
    Physical review A 110, 5 (2024)
    Open access:
  4. Mutual friction and diffusion of two-dimensional quantum vortices
    Zain Mehdi, J. J. Hope, Stuart S. Szigeti, A. S. Bradley
    Physical Review Research 5, 1 (2023)
    Open access:
  5. Vortex generation in stirred binary Bose-Einstein condensates
    Anacé N. da Silva, R. Kishor Kumar, A. S. Bradley, Lauro Tomio
    Physical review A 107, 3 (2023)
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  6. Scaling dynamics of the ultracold Bose gas
    A. S. Bradley, Jordan Clarke, Tyler W. Neely, Brian P. Anderson
    Physical review A 106, 5 (2022)
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  7. Spectral analysis for compressible quantum fluids
    A. S. Bradley, R. Kishor Kumar, Sukla Pal, Xiaoquan Yu
    Physical review A 106, 4 (2022)
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  8. Turbulent Relaxation to Equilibrium in a Two-Dimensional Quantum Vortex Gas
    Matthew T. Reeves, Kwan Goddard-Lee, Guillaume Gauthier, Oliver R. Stockdale, Hayder Salman, Timothy Edmonds, Xiaoquan Yu, A. S. Bradley, Mark Baker, Halina Rubinsztein‐Dunlop, Matthew J. Davis, Tyler W. Neely
    Physical Review X 12, 1 (2022)
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  9. Superflow decay in a toroidal Bose gas: The effect of quantum and thermal fluctuations
    Zain Mehdi, A. S. Bradley, J. J. Hope, Stuart S. Szigeti
    SciPost Physics 11, 4 (2021)
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  10. Neutral Vortex Necklace in a Trapped Planar Superfluid
    Michael MacCormick Cawte, Matthew T. Reeves, A. S. Bradley
    Journal of Low Temperature Physics 202, 3-4 310 (2021)
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  11. Steady states, squeezing, and entanglement in intracavity triplet down conversion
    Mathew D. E. Denys, M.K. Olsen, Luke S. Trainor, Harald G. L. Schwefel, A. S. Bradley
    Optics Communications 484, 126699 (2021)
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  12. Dynamics of hot Bose-Einstein condensates: stochastic Ehrenfest relations for number and energy damping
    R. G. McDonald, Peter Barnett, Fradom Atayee, A. S. Bradley
    SciPost Physics 8, 2 (2020)
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  13. Coherent vortex dynamics in a strongly interacting superfluid on a silicon chip
    Yauhen Sachkou, Christopher G. Baker, Glen I. Harris, Oliver R. Stockdale, Stefan Forstner, Matthew T. Reeves, Xin He, D. L. McAuslan, A. S. Bradley, Matthew J. Davis, Warwick P. Bowen
    Science 366, 6472 1480 (2019)
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  14. Giant vortex clusters in a two-dimensional quantum fluid
    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)
    Open access:
  15. Thermally robust spin correlations between two 85Rb atoms in an optical microtrap
    Pimonpan Sompet, Stuart S. Szigeti, E. Schwartz, A. S. Bradley, Mikkel F. Andersen
    Nature Communications 10, 1 (2019)
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  16. Snell's Law for a vortex dipole in a Bose-Einstein condensate
    Michael MacCormick Cawte, Xiaoquan Yu, Brian P. Anderson, A. S. Bradley
    SciPost Physics 6, 3 (2019)
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  17. Mesoscopic Dynamical Differences from Quantum State Preparation in a Bose-Hubbard Trimer
    M. K. Olsen, Tyler W. Neely, A. S. Bradley
    Physical Review Letters 120, 23 (2018)
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  18. Enstrophy Cascade in Decaying Two-Dimensional Quantum Turbulence
    Matthew T. Reeves, T. P. Billam, Xiaoquan Yu, A. S. Bradley
    Physical Review Letters 119, 18 (2017)
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  19. Emergent Non-Eulerian Hydrodynamics of Quantum Vortices in Two Dimensions
    Xiaoquan Yu, A. S. Bradley
    Physical Review Letters 119, 18 (2017)
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  20. Quantum-correlated twin-atom laser from a Bose-Hubbard system
    M. K. Olsen, A. S. Bradley
    Physical review A 95, 6 (2017)
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  21. Theory of the vortex-clustering transition in a confined two-dimensional quantum fluid
    Xiaoquan Yu, T. P. Billam, Jun Nian, Matthew T. Reeves, A. S. Bradley
    Physical review A 94, 2 (2016)
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  22. Reservoir interactions of a vortex in a trapped three-dimensional Bose-Einstein condensate
    S. J. Rooney, A. Joy Allen, U. Zülicke, N. P. Proukakis, A. S. Bradley
    Physical review A 93, 6 (2016)
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  23. Brownian motion of a matter-wave bright soliton moving through a thermal cloud of distinct atoms
    R. G. McDonald, A. S. Bradley
    Physical review A 93, 6 (2016)
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  24. Errata: Numerical representation of quantum states in the positive-P and Wigner representations
    M.K. Olsen, R.J. Lewis-Swan, A. S. Bradley
    Optics Communications 370, 327 (2016)
  25. Low-dimensional stochastic projected Gross-Pitaevskii equation
    A. S. Bradley, S. J. Rooney, R. G. McDonald
    Physical Review A 92, 3 (2015)
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  26. Reservoir interactions during Bose-Einstein condensation: Modified critical scaling in the Kibble-Zurek mechanism of defect formation
    R. G. McDonald, A. S. Bradley
    Physical Review A 92, 3 (2015)
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  27. Coherence and linewidth of a continuously pumped atom laser at finite temperature
    Geoffrey M. Lee, Simon A. Haine, A. S. Bradley, Matthew J. Davis
    Physical Review A 92, 1 (2015)
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  28. Quantum ultracold atomtronics
    M. K. Olsen, A. S. Bradley
    Physical Review A 91, 4 (2015)
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  29. Identifying a Superfluid Reynolds Number via Dynamical Similarity
    Matthew T. Reeves, T. P. Billam, B. P. Anderson, A. S. Bradley
    Physical Review Letters 114, 15 (2015)
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  30. Oscillons in coupled Bose-Einstein condensates
    Shih-Wei Su, Shih-Chuan Gou, I-Kang Liu, A. S. Bradley, O. Fialko, Joachim Brand
    Physical Review A 91, 2 (2015)
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  31. Spectral energy transport in two-dimensional quantum vortex dynamics
    T. P. Billam, Matthew T. Reeves, A. S. Bradley
    Physical Review A 91, 2 (2015)
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  32. Stochastic projected Gross-Pitaevskii equation for spinor and multicomponent condensates
    A. S. Bradley, P. B. Blakie
    Physical Review A 90, 2 (2014)
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  33. Signatures of coherent vortex structures in a disordered two-dimensional quantum fluid
    Matthew T. Reeves, T. P. Billam, Brian P. Anderson, A. S. Bradley
    Physical Review A 89, 5 (2014)
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  34. Dynamic and energetic stabilization of persistent currents in Bose-Einstein condensates
    Kody J. H. Law, Tyler W. Neely, P. G. Kevrekidis, Brian P. Anderson, A. S. Bradley, R. Carretero-González
    Physical Review A 89, 5 (2014)
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  35. Onsager-Kraichnan Condensation in Decaying Two-Dimensional Quantum Turbulence
    T. P. Billam, Matthew T. Reeves, B. P. Anderson, A. S. Bradley
    Physical Review Letters 112, 14 (2014)
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  36. Numerical method for the stochastic projected Gross-Pitaevskii equation
    S. J. Rooney, P. B. Blakie, A. S. Bradley
    Physical Review E 89, 1 (2014)
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  37. Persistent-current formation in a high-temperature Bose-Einstein condensate: An experimental test for classical-field theory
    S. J. Rooney, Tyler W. Neely, Brian P. Anderson, A. S. Bradley
    Physical Review A 88, 6 (2013)
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  38. Characteristics of Two-Dimensional Quantum Turbulence in a Compressible Superfluid
    Tyler W. Neely, A. S. Bradley, E. Carlo Samson, S. J. Rooney, E. M. Wright, Kody J. H. Law, R. Carretero-González, P. G. Kevrekidis, Matthew J. Davis, Brian P. Anderson
    Physical Review Letters 111, 23 (2013)
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  39. Kibble-Zurek Scaling and its Breakdown for Spontaneous Generation of Josephson Vortices in Bose-Einstein Condensates
    Shih-Wei Su, Shih-Chuan Gou, A. S. Bradley, O. Fialko, Joachim Brand
    Physical Review Letters 110, 21 (2013)
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  40. C-Field Methods for Non-Equilibrium Bose Gases
    Matthew J. Davis, Tod M. Wright, P. B. Blakie, A. S. Bradley, Rob J. Ballagh, C. W. Gardiner
    Cold atoms , 163 (2013)
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  41. Inverse Energy Cascade in Forced Two-Dimensional Quantum Turbulence
    Matthew T. Reeves, T. P. Billam, Brian P. Anderson, A. S. Bradley
    Physical Review Letters 110, 10 (2013)
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  42. Stochastic projected Gross-Pitaevskii equation
    S. J. Rooney, P. B. Blakie, A. S. Bradley
    Physical Review A 86, 5 (2012)
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  43. Classical and quantum regimes of two-dimensional turbulence in trapped Bose-Einstein condensates
    Matthew T. Reeves, Brian P. Anderson, A. S. Bradley
    Physical Review A 86, 5 (2012)
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  44. Energy Spectra of Vortex Distributions in Two-Dimensional Quantum Turbulence
    A. S. Bradley, Brian P. Anderson
    Physical Review X 2, 4 (2012)
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  45. Quantum Tunneling of a Vortex between Two Pinning Potentials
    O. Fialko, A. S. Bradley, Joachim Brand
    Physical Review Letters 108, 1 (2012)
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  46. Suppression of Kelvon-induced decay of quantized vortices in oblate Bose-Einstein condensates
    S. J. Rooney, P. B. Blakie, Brian P. Anderson, A. S. Bradley
    Physical Review A 84, 2 (2011)
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  47. Analysis of a continuous-variable quadripartite cluster state from a single optical parametric oscillator
    S. L. W. Midgley, M. K. Olsen, A. S. Bradley, Olivier Pfister
    Physical Review A 82, 5 (2010)
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  48. Geometric scale invariance as a route to macroscopic degeneracy: Loading a toroidal trap with a Bose or Fermi gas
    D. Baillie, P. B. Blakie, A. S. Bradley
    Physical Review A 82, 1 (2010)
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  49. Quadripartite continuous-variable entanglement via quadruply concurrent down-conversion
    S. L. W. Midgley, A. S. Bradley, Oliver Pfister, M. K. Olsen
    Physical Review A 81, 6 (2010)
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  50. Observation of Vortex Dipoles in an Oblate Bose-Einstein Condensate
    Tyler W. Neely, E. Carlo Samson, A. S. Bradley, Matthew J. Davis, Brian P. Anderson
    Physical Review Letters 104, 16 (2010)
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  51. Decay of a quantum vortex: Test of nonequilibrium theories for warm Bose-Einstein condensates
    S. J. Rooney, A. S. Bradley, P. B. Blakie
    Physical Review A 81, 2 (2010)
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  52. Nonequilibrium dynamics of vortex arrest in a finite-temperature Bose-Einstein condensate
    Tod M. Wright, A. S. Bradley, R. J. Ballagh
    Physical Review A 81, 1 (2010)
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  53. Finite-temperature dynamics of a single vortex in a Bose-Einstein condensate: Equilibrium precession and rotational symmetry breaking
    Tod M. Wright, A. S. Bradley, R. J. Ballagh
    Physical Review A 80, 5 (2009)
  54. Numerical method for evolving the dipolar projected Gross-Pitaevskii equation
    P. B. Blakie, Christopher Ticknor, A. S. Bradley, A. Martin, Matthew J. Davis, Yuki Kawaguchi
    Physical Review E 80, 1 (2009)
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  55. Numerical representation of quantum states in the positive-P and Wigner representations
    M. K. Olsen, A. S. Bradley
    Optics Communications 282, 19 3924 (2009)
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  56. Scale-invariant thermodynamics of a toroidally trapped Bose gas
    A. S. Bradley
    Physical Review A 79, 3 (2009)
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  57. Dynamical thermalization and vortex formation in stirred two-dimensional Bose-Einstein condensates
    Tod M. Wright, R. J. Ballagh, A. S. Bradley, P. B. Blakie, C. W. Gardiner
    Physical Review A 78, 6 (2008)
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  58. Spontaneous vortices in the formation of Bose–Einstein condensates
    Chad Weiler, Tyler W. Neely, David R. Scherer, A. S. Bradley, Matthew J. Davis, Brian P. Anderson
    Nature 455, 7215 948 (2008)
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  59. Dynamics and statistical mechanics of ultra-cold Bose gases using c-field techniques
    P. B. Blakie, A. S. Bradley, Matthew J. Davis, R. J. Ballagh, C. W. Gardiner
    Advances In Physics 57, 5 363 (2008)
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  60. From squeezed atom lasers to teleportation of massive articles
    M. K. Olsen, Simon A. Haine, A. S. Bradley, J. J. Hope
    The European Physical Journal Special Topics 160, 1 331 (2008)
  61. Bose-Einstein condensation from a rotating thermal cloud: Vortex nucleation and lattice formation
    A. S. Bradley, C. W. Gardiner, Matthew J. Davis
    Physical Review A 77, 3 (2008)
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  62. Bright bichromatic entanglement and quantum dynamics of sum frequency generation
    M. K. Olsen, A. S. Bradley
    Physical Review A 77, 2 (2008)
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  63. Tripartite entanglement and threshold properties of coupled intracavity down-conversion and sum-frequency generation
    C. Pennarun, A. S. Bradley, M. K. Olsen
    Physical Review A 76, 6 (2007)
  64. Raman scheme to measure the quantum statistics of an atom laser beam
    A. S. Bradley, M. K. Olsen, Simon A. Haine, J. J. Hope
    Physical Review A 76, 3 (2007)
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  65. Quantum de Laval nozzle: Stability and quantum dynamics of sonic horizons in a toroidally trapped Bose gas containing a superflow
    P. Jain, A. S. Bradley, C. W. Gardiner
    Physical Review A 76, 2 (2007)
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  66. Continuous variable tripartite entanglement and Einstein-Podolsky-Rosen correlations from triple nonlinearities
    M. K. Olsen, A. S. Bradley, M. D. Reid
    Optics and Spectroscopy 103, 2 187 (2007)
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  67. Quantum statistical measurements of an atom laser beam
    M. K. Olsen, A. S. Bradley, Simon A. Haine, J. J. Hope
    Nuclear Physics A 790, 1-4 733c (2007)
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  68. Quantum depletion of collapsing Bose-Einstein condensates
    Sebastian Wüster, Beata J. Da̧browska-Wüster, A. S. Bradley, Matthew J. Davis, P. B. Blakie, J. J. Hope, C. M. Savage
    Physical Review A 75, 4 (2007)
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  69. Asymmetric polychromatic tripartite entanglement from interlinkedχ(2)parametric interactions
    M. K. Olsen, A. S. Bradley
    Physical Review A 74, 6 (2006)
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  70. Continuous variable tripartite entanglement and Einstein–Podolsky–Rosen correlations from triple nonlinearities
    M. K. Olsen, A. S. Bradley, M. D. Reid
    Journal of Physics B Atomic Molecular and Optical Physics 39, 11 2515 (2006)
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  71. Three-body recombination of ultracold Bose gases using the truncated Wigner method
    Aidan Norrie, R. J. Ballagh, C. W. Gardiner, A. S. Bradley
    Physical Review A 73, 4 (2006)
  72. Continuous variable tripartite entanglement from twin nonlinearities
    M. K. Olsen, A. S. Bradley
    Journal of Physics B Atomic Molecular and Optical Physics 39, 1 127 (2005)
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  73. Properties of the stochastic Gross–Pitaevskii equation: finite temperature Ehrenfest relations and the optimal plane wave representation
    A. S. Bradley, P. B. Blakie, C. W. Gardiner
    Journal of Physics B Atomic Molecular and Optical Physics 38, 23 4259 (2005)
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  74. Bright tripartite entanglement in triply concurrent parametric oscillation
    A. S. Bradley, M. K. Olsen, Olivier Pfister, Raphael C. Pooser
    Physical Review A 72, 5 (2005)
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  75. Phase-space analysis of bosonic spontaneous emission
    M. K. Olsen, L. I. Plimak, S. Rebić, A. S. Bradley
    Optics Communications 254, 4-6 271 (2005)
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  76. Fock-state dynamics in Raman photoassociation of Bose-Einstein condensates
    M. K. Olsen, A. S. Bradley, S. B. Cavalcanti
    Physical Review A 70, 3 (2004)
  77. Steady-state quantum statistics of a non-Markovian atom laser. II
    A. S. Bradley, J. J. Hope, M. J. Collett
    Physical Review A 68, 6 (2003)
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  78. Theory of Ramsey spectroscopy and anomalous segregation in ultracold rubidium
    A. S. Bradley, C. W. Gardiner
    Journal of Physics B Atomic Molecular and Optical Physics 35, 20 4299 (2002)
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  79. Analysis ofg2for the cold collision frequency shift in the hydrogen condensate experiments
    C. W. Gardiner, A. S. Bradley
    Journal of Physics B Atomic Molecular and Optical Physics 34, 23 4663 (2001)
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  80. Theory of the cold collision frequency shift in 1S-2S spectroscopy of Bose-Einstein-condensed and non-condensed hydrogen
    C. W. Gardiner, A. S. Bradley
    Journal of Physics B Atomic Molecular and Optical Physics 34, 23 4673 (2001)
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