Stochastic growth dynamics and composite defects in quenched immiscible binary condensates (2016)
Journal Article
Liu, I., Pattinson, R., Billam, T., Gardiner, S., Cornish, S., Huang, T., …Proukakis, N. (2016). Stochastic growth dynamics and composite defects in quenched immiscible binary condensates. Physical Review A, 93(2), Article 023628. https://doi.org/10.1103/physreva.93.023628

We study the sensitivity of coupled condensate formation dynamics on the history of initial stochastic domain formation in the context of instantaneously quenched elongated harmonically trapped immiscible two-component atomic Bose gases. The spontane... Read More about Stochastic growth dynamics and composite defects in quenched immiscible binary condensates.

Analysis beyond the Thomas-Fermi approximation of the density profiles of a miscible two-component Bose-Einstein condensate (2015)
Journal Article
Polo, J., Ahufinger, V., Mason, P., Sridhar, S., Billam, T., & Gardiner, S. (2015). Analysis beyond the Thomas-Fermi approximation of the density profiles of a miscible two-component Bose-Einstein condensate. Physical Review A, 91(5), Article 053626. https://doi.org/10.1103/physreva.91.053626

We investigate a harmonically trapped two-component Bose-Einstein condensate within the miscible regime, close to its boundaries, for different ratios of effective intra- and interspecies interactions. We derive analytically a universal equation for... Read More about Analysis beyond the Thomas-Fermi approximation of the density profiles of a miscible two-component Bose-Einstein condensate.

Controlled formation and reflection of a bright solitary matter-wave (2013)
Journal Article
Marchant, A., Billam, T., Wiles, T., Yu, M., Gardiner, S., & Cornish, S. (2013). Controlled formation and reflection of a bright solitary matter-wave. Nature Communications, 4, Article 1865. https://doi.org/10.1038/ncomms2893

Bright solitons are non-dispersive wave solutions, arising in a diverse range of nonlinear, one-dimensional systems, including atomic Bose–Einstein condensates with attractive interactions. In reality, cold-atom experiments can only approach the idea... Read More about Controlled formation and reflection of a bright solitary matter-wave.

Second-order number-conserving description of nonequilibrium dynamics in finite-temperature Bose-Einstein condensates (2013)
Journal Article
Billam, T., Mason, P., & Gardiner, S. (2013). Second-order number-conserving description of nonequilibrium dynamics in finite-temperature Bose-Einstein condensates. Physical Review A, 87(3), Article 033628. https://doi.org/10.1103/physreva.87.033628

While the Gross-Pitaevskii equation is well established as the canonical dynamical description of atomic Bose-Einstein condensates (BECs) at zero temperature, describing the dynamics of BECs at finite temperatures remains a difficult theoretical prob... Read More about Second-order number-conserving description of nonequilibrium dynamics in finite-temperature Bose-Einstein condensates.

Equilibrium solutions for immiscible two-species Bose-Einstein condensates in perturbed harmonic traps (2013)
Journal Article
Pattinson, R., Billam, T., Gardiner, S., McCarron, D., Cho, H., Cornish, S., …Proukakis, N. (2013). Equilibrium solutions for immiscible two-species Bose-Einstein condensates in perturbed harmonic traps. Physical Review A, 87(1), Article 013625. https://doi.org/10.1103/physreva.87.013625

We investigate the mean-field equilibrium solutions for a two-species immiscible Bose-Einstein condensate confined by a harmonic confinement with additional linear perturbations. We observe a range of equilibrium density structures, including ball an... Read More about Equilibrium solutions for immiscible two-species Bose-Einstein condensates in perturbed harmonic traps.

Bright matter-wave soliton collisions at narrow barriers (2012)
Journal Article
Helm, J., Billam, T., & Gardiner, S. (2012). Bright matter-wave soliton collisions at narrow barriers. Physical Review A, 85(5), Article 053621. https://doi.org/10.1103/physreva.85.053621

We study fast-moving bright solitons in the focusing nonlinear Schrödinger equation perturbed by a narrow Gaussian potential barrier. In particular, we present a general and comprehensive analysis of the case where two fast-moving bright solitons col... Read More about Bright matter-wave soliton collisions at narrow barriers.

Coherence and instability in a driven Bose–Einstein condensate: a fully dynamical number-conserving approach (2012)
Journal Article
Billam, T., & Gardiner, S. (2012). Coherence and instability in a driven Bose–Einstein condensate: a fully dynamical number-conserving approach. New Journal of Physics, 14, Article 013038. https://doi.org/10.1088/1367-2630/14/1/013038

We consider a Bose–Einstein condensate driven by periodic delta-kicks. In contrast to first-order descriptions, which predict rapid, unbounded growth of the noncondensate in resonant parameter regimes, the consistent treatment of condensate depletion... Read More about Coherence and instability in a driven Bose–Einstein condensate: a fully dynamical number-conserving approach.

Variational determination of approximate bright matter-wave soliton solutions in anisotropic traps (2012)
Journal Article
Billam, T., Wrathmall, S., & Gardiner, S. (2012). Variational determination of approximate bright matter-wave soliton solutions in anisotropic traps. Physical Review A, 85(1), Article 013627. https://doi.org/10.1103/physreva.85.013627

We consider the ground state of an attractively interacting atomic Bose-Einstein condensate in a prolate, cylindrically symmetric harmonic trap. If a true quasi-one-dimensional limit is realized, then for sufficiently weak axial trapping this ground... Read More about Variational determination of approximate bright matter-wave soliton solutions in anisotropic traps.

Realizing bright-matter-wave-soliton collisions with controlled relative phase (2011)
Journal Article
Billam, T., Cornish, S., & Gardiner, S. (2011). Realizing bright-matter-wave-soliton collisions with controlled relative phase. Physical Review A, 83(4), Article 041602. https://doi.org/10.1103/physreva.83.041602

We propose a method to split the ground state of an attractively interacting atomic Bose-Einstein condensate into two bright solitary waves with controlled relative phase and velocity. We analyze the stability of these waves against their subsequent... Read More about Realizing bright-matter-wave-soliton collisions with controlled relative phase.

Quantum resonances in the delta-kicked harmonic oscillator (2009)
Journal Article
Billam, T., & Gardiner, S. (2009). Quantum resonances in the delta-kicked harmonic oscillator. Physical Review A, 80(2), https://doi.org/10.1103/physreva.80.023414

Under certain conditions, the quantum delta-kicked harmonic oscillator displays quantum resonances. We consider an atom-optical realization of the delta-kicked harmonic oscillator and present a theoretical discussion of the quantum resonances that co... Read More about Quantum resonances in the delta-kicked harmonic oscillator.