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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.

Quantum theory of bright matter-wave solitons in harmonic confinement (2012)
Journal Article
Holdaway, D., Weiss, C., & Gardiner, S. (2012). Quantum theory of bright matter-wave solitons in harmonic confinement. Physical Review A, 85(5), Article 053618. https://doi.org/10.1103/physreva.85.053618

This paper investigates bright quantum-matter-wave solitons beyond the Gross-Pitaevskii equation (GPE). As proposals for interferometry and creating nonlocal quantum superpositions have been formed, it has become necessary to investigate effects not... Read More about Quantum theory of bright matter-wave solitons in harmonic confinement.

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.

Rotational response of two-component Bose-Einstein condensates in ring traps (2010)
Journal Article
Halkyard, P., Jones, M., & Gardiner, S. (2010). Rotational response of two-component Bose-Einstein condensates in ring traps. Physical Review A, 81(6), Article 061602. https://doi.org/10.1103/physreva.81.061602

We consider a two-component Bose-Einstein condensate in a ring trap in a rotating frame and show how to determine the response of such a configuration to being in a rotating frame via accumulation of a Sagnac phase. This may be accomplished through e... Read More about Rotational response of two-component Bose-Einstein condensates in ring traps.

Conical intersections in laboratory coordinates with ultracold molecules (2009)
Journal Article
Wallis, A. O. G., Gardiner, S. A., & Hutson, J. M. (2009). Conical intersections in laboratory coordinates with ultracold molecules. Physical Review Letters, 103(8), Article 083201. https://doi.org/10.1103/physrevlett.103.083201

For two states of opposite parity that cross as a function of an external magnetic field, the addition of an electric field will break the symmetry and induce an avoided crossing. A suitable arrangement of fields may be used to create a conical inter... Read More about Conical intersections in laboratory coordinates with ultracold molecules.

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.

Fractional resonances in the atom-optical delta-kicked accelerator (2009)
Journal Article
Saunders, M., Halkyard, P., Gardiner, S., & Challis, K. (2009). Fractional resonances in the atom-optical delta-kicked accelerator. Physical Review A, 79(2), https://doi.org/10.1103/physreva.79.023423

We consider resonant dynamics in a dilute atomic gas falling under gravity through a periodically pulsed standing-wave laser field. Our numerical calculations are based on a Monte Carlo method for an incoherent mixture of noninteracting plane waves,... Read More about Fractional resonances in the atom-optical delta-kicked accelerator.

Power-law behavior in the quantum-resonant evolution of the delta-kicked accelerator (2008)
Journal Article
Halkyard, P., Saunders, M., Gardiner, S., & Challis, K. (2008). Power-law behavior in the quantum-resonant evolution of the delta-kicked accelerator. Physical Review A, 78(6), https://doi.org/10.1103/physreva.78.063401

We consider the atom-optical delta-kicked accelerator when the initial momentum distribution is symmetric. We demonstrate the existence of quantum-resonant dynamics, and derive analytic expressions for the system evolution. In particular, we consider... Read More about Power-law behavior in the quantum-resonant evolution of the delta-kicked accelerator.

Bright solitary-matter-wave collisions in a harmonic trap: Regimes of solitonlike behavior (2008)
Journal Article
Martin, A., Adams, C., & Gardiner, S. (2008). Bright solitary-matter-wave collisions in a harmonic trap: Regimes of solitonlike behavior. Physical Review A, 77(1), https://doi.org/10.1103/physreva.77.013620

Systems of solitary waves in the one-dimensional Gross-Pitaevskii equation, which models a trapped atomic Bose-Einstein condensate, are investigated theoretically. To analyze the soliton nature of these solitary waves, a particle analogy for the soli... Read More about Bright solitary-matter-wave collisions in a harmonic trap: Regimes of solitonlike behavior.

Manifestation of quantum resonances and antiresonances in a finite temperature dilute atomic gas (2007)
Journal Article
Saunders, M., Halkyard, P., Challis, K., & Gardiner, S. (2007). Manifestation of quantum resonances and antiresonances in a finite temperature dilute atomic gas. Physical Review A, 76(4), https://doi.org/10.1103/physreva.76.043415

We investigate the effect of temperature on resonant and antiresonant dynamics in a dilute atomic gas kicked periodically by a standing-wave laser field. Our numerical calculations are based on a Monte Carlo method for an incoherent mixture of nonint... Read More about Manifestation of quantum resonances and antiresonances in a finite temperature dilute atomic gas.

A number-conserving approach to a minimal self-consistent treatment of condensate and non-condensate dynamics in a degenerate Bose gas (2007)
Journal Article
Gardiner, S., & Morgan, S. (2007). A number-conserving approach to a minimal self-consistent treatment of condensate and non-condensate dynamics in a degenerate Bose gas. Physical Review A, 75, https://doi.org/10.1103/physreva.75.043621

We describe a number-conserving approach to the dynamics of Bose-Einstein condensed dilute atomic gases. This builds upon the works of Gardiner [Phys. Rev. A 56, 1414 (1997)] and Castin and Dum [Phys. Rev. A 57, 3008 (1998)]. We consider what is effe... Read More about A number-conserving approach to a minimal self-consistent treatment of condensate and non-condensate dynamics in a degenerate Bose gas.

Bright matter-wave soliton collisions in a harmonic trap : regular and chaotic dynamics (2007)
Journal Article
Martin, A., Adams, C., & Gardiner, S. (2007). Bright matter-wave soliton collisions in a harmonic trap : regular and chaotic dynamics. Physical Review Letters, 98(2), https://doi.org/10.1103/physrevlett.98.020402

Collisions between bright solitary waves in the 1D Gross-Pitaevskii equation with a harmonic potential, which models a trapped atomic Bose-Einstein condensate, are investigated theoretically. A particle analogy for the solitary waves is formulated an... Read More about Bright matter-wave soliton collisions in a harmonic trap : regular and chaotic dynamics.

Quantum Accelerator Modes from the Farey Tree (2006)
Journal Article
Buchleitner, A., d'Arcy, M., Fishman, S., Gardiner, S., Guarneri, I., Ma, Z. -., …Summy, G. (2006). Quantum Accelerator Modes from the Farey Tree. Physical Review Letters, 96(16), https://doi.org/10.1103/physrevlett.96.164101

We show that mode locking finds a purely quantum nondissipative counterpart in atom-optical quantum accelerator modes. These modes are formed by exposing cold atoms to periodic kicks in the direction of the gravitational field. They are anchored to g... Read More about Quantum Accelerator Modes from the Farey Tree.

Quantum random walks using quantum accelerator modes (2006)
Journal Article
Ma, Z. -., Burnett, K., d'Arcy, M., & Gardiner, S. (2006). Quantum random walks using quantum accelerator modes. Physical Review A, 73(1), https://doi.org/10.1103/physreva.73.013401

We discuss the use of high-order quantum accelerator modes to achieve an atom optical realization of a biased quantum random walk. We first discuss how one can create coexistent quantum accelerator modes, and hence how momentum transfer that depends... Read More about Quantum random walks using quantum accelerator modes.

Quantum-mechanical cumulant dynamics near stable periodic orbits in phase space: Application to the classical-like dynamics of quantum accelerator modes (2005)
Journal Article
Bach, R., Burnett, K., d'Arcy, M., & Gardiner, S. (2005). Quantum-mechanical cumulant dynamics near stable periodic orbits in phase space: Application to the classical-like dynamics of quantum accelerator modes. Physical Review A, 71, https://doi.org/10.1103/physreva.71.033417

We formulate a general method for the study of semiclassical-like dynamics in stable regions of a mixed phase space, in order to theoretically study the dynamics of quantum accelerator modes. In the simplest case, this involves determining solutions,... Read More about Quantum-mechanical cumulant dynamics near stable periodic orbits in phase space: Application to the classical-like dynamics of quantum accelerator modes.

Gravity-sensitive quantum dynamics in cold atoms (2004)
Journal Article
Ma, Z., d'Arcy, M., & Gardiner, S. (2004). Gravity-sensitive quantum dynamics in cold atoms. Physical Review Letters, 93, https://doi.org/10.1103/physrevlett.93.164101

We subject a falling cloud of cold cesium atoms to periodic kicks from a sinusoidal potential created by a vertical standing wave of laser light. By controllably accelerating the potential, we show quantum accelerator mode dynamics to be highly sensi... Read More about Gravity-sensitive quantum dynamics in cold atoms.

Adiabatic association of ultracold molecules via magnetic-field tunable interactions (2004)
Journal Article
Góral, K., Köhler, T., Gardiner, S., Tiesinga, E., & Julienne, P. (2004). Adiabatic association of ultracold molecules via magnetic-field tunable interactions. Journal of Physics B: Atomic, Molecular and Optical Physics, 37(17), 3457-3500. https://doi.org/10.1088/0953-4075/37/17/006

We consider in detail the situation of applying a time-dependent external magnetic field to a 87Rb atomic Bose–Einstein condensate held in a harmonic trap, in order to adiabatically sweep the interatomic interactions across a Feshbach resonance to pr... Read More about Adiabatic association of ultracold molecules via magnetic-field tunable interactions.