Kibble-Zurek Scaling and its Breakdown for Spontaneous Generation of Josephson Vortices in Bose-Einstein Condensates

Su, Shih-Wei; Gou, Shih-Chuan; Bradley, Ashton S.; Fialko, O.; Brand, Joachim

doi:10.1103/physrevlett.110.215302

Cited by 69 publications

(77 citation statements)

References 36 publications

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“…The theory has also been applied to the dissipative dynamics of topological excitations at high temperature [25,26,52,55,56]. A stochastic Gross-Pitaevskii equation formalism has also been developed by Stoof and coworkers [33,[57][58][59][60][61][62][63][64][65][66] that does not impose an explicit projector, but yields a similar description of the low energy region of the system near equilibrium (also see [67][68][69]). …”

Section: Introductionmentioning

confidence: 99%

Stochastic projected Gross-Pitaevskii equation for spinor and multicomponent condensates

Bradley

Blakie

2014

Phys. Rev. A

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A stochastic Gross-Pitaevskii equation is derived for partially condensed Bose gas systems subject to binary contact interactions. The theory we present provides a classical-field theory suitable for describing dissipative dynamics and phase transitions of spinor and multi-component Bose gas systems comprised of an arbitrary number of distinct interacting Bose fields. A new class of dissipative processes involving distinguishable particle interchange between coherent and incoherent regions of phase-space is identified. The formalism and its implications are illustrated for two-component mixtures and spin-1 Bose-Einstein condensates. For systems comprised of atoms of equal mass, with thermal reservoirs that are close to equilibrium, the dissipation rates of the theory are reduced to analytical expressions that may be readily evaluated. The unified treatment of binary contact interactions presented here provides a theory with broad relevance for quasi-equilibrium and far-from-equilibrium Bose-Einstein condensates.

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Section: Introductionmentioning

confidence: 99%

Stochastic projected Gross-Pitaevskii equation for spinor and multicomponent condensates

Bradley

Blakie

2014

Phys. Rev. A

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“…A natural outcome of this assumption is, at finite temperatures the maxima of the condensate and non-condensate densities must lie along the axis of the toroid. Hence, the KZ scaling laws obtained in the previous works [48,49,52] are applicable in toroidal condensates only when the parameters of the toroid satisfies the conditions m U 0  , and this is an additional criterion to ensure the alignment of the thermal fluctuations. Otherwise, as observed in the present results, the non-condensate or fluctuations distribution have a different geometry, and the system deviates from the 1D approximation.…”

Section: Kz Scaling and Fluctuationsmentioning

confidence: 99%

“…The KZ mechanism has been the subject of intense investigations in toroidal or multiply connected condensates [48,49,52]. One key simplifying assumption in all the works is the consideration of a toroidal condensate as a 1D system with periodic boundary condition.…”

Section: Kz Scaling and Fluctuationsmentioning

confidence: 99%

Geometry-induced modification of fluctuation spectrum in quasi-two-dimensional condensates

Roy

Angom

2016

New J. Phys.

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We report the structural transformation of the low-lying spectral modes, especially the Kohn mode, from radial to circular topology as harmonic confining potential is modified to a toroidal one, and this corresponds to a transition from simply to multiply connected geometry. For this we employ the Hartree-Fock-Bogoliubov theory to examine the evolution of low energy quasiparticles. We, then, use the Hartree-Fock-Bogoliubov theory with the Popov approximation to demonstrate the two striking features of quantum and thermal fluctuations. At T=0, the non-condensate density due to interaction induced quantum fluctuations increases with the transformation from pancake to toroidal geometry. The other feature is, there is a marked change in the density profile of the non-condensate density at finite temperatures with the modification of trapping potential. In particular, the condensate and non-condensate density distributions have overlapping maxima in the toroidal condensate, which is in stark contrast to the case of pancake geometry. The genesis of this difference lies in the nature of the thermal fluctuations.

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“…Previous theoretical investigations [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] have drawn considerable interest to systems of coupled circular BECs. In this vein, two parallel coaxial BEC rings, separated in the axial direction by a potential barrier, were considered in the context of the spontaneous generation of vortex lines [17] and defects by means of the Kibble-Zurek mechanism [3]. It is worth to mention that binary systems with incoherent nonlinear interaction between their components conserve the norms in each component separately.…”

Section: Introductionmentioning

confidence: 99%

Symmetry Breaking in Interacting Ring-Shaped Superflows of Bose–Einstein Condensates

et al. 2019

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We demonstrate that the evolution of superflows in interacting persistent currents of ultracold gases is strongly affected by symmetry breaking of the quantum vortex dynamics. We study counterpropagating superflows in a system of two parallel rings in regimes of weak (a Josephson junction with tunneling through the barrier) and strong (rings merging across a reduced barrier) interactions. For the weakly interacting toroidal Bose-Einstein condensates, formation of rotational fluxons (Josephson vortices) is associated with spontaneous breaking of the rotational symmetry of the tunneling superflows. The influence of a controllable symmetry breaking on the final state of the merging counter-propagating superflows is investigated in the framework of a weakly dissipative mean-field model. It is demonstrated that the population imbalance between the merging flows and the breaking of the underlying rotational symmetry can drive the double-ring system to final states with different angular momenta.PACS numbers:

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Kibble-Zurek Scaling and its Breakdown for Spontaneous Generation of Josephson Vortices in Bose-Einstein Condensates

Cited by 69 publications

References 36 publications

Stochastic projected Gross-Pitaevskii equation for spinor and multicomponent condensates

Stochastic projected Gross-Pitaevskii equation for spinor and multicomponent condensates

Geometry-induced modification of fluctuation spectrum in quasi-two-dimensional condensates

Symmetry Breaking in Interacting Ring-Shaped Superflows of Bose–Einstein Condensates

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