Dipolar dark solitons

We study the family of static and moving dark solitons in quasi-one-dimensional dipolar BoseEinstein condensates, exploring their modified form and interactions. The density dip of the soliton acts as a giant anti-dipole which adds a non-local contribution to the conventional local solitonsoliton interaction. We map out the stability diagram as a function of the strength and polarization direction of the atomic dipoles, identifying both roton and phonon instabilities. Away from these instabilities, the solitons collide elastically. Varying the polarization direction relative to the condensate axis enables tuning of this non-local interaction between repulsive and attractive; the latter case supports unusual dark soliton bound states. Remarkably, these bound states are themselves shown to behave like solitons, emerging unscathed from collisions with each other.

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“…Note Added: After completing this research we became aware of the manuscript [68] which obtains results related to ours.…”

Section: Discussionmentioning

confidence: 99%

Controllable nonlocal interactions between dark solitons in dipolar condensates

et al. 2015

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“…several individual solitons forming bound objects) and also breathers, which are single solitonic entities that can be thought of as excited states of the focussing nonlinear Schrödinger equation, which have recently been engineered experimentally with matter waves for the first time [70] using an attractive gas of 85 Rb. Soliton molecules have been studied in various guises within the context of ultracold matter, for example the realization of degeneracy with atomic species possessing significant dipole-dipole interactions has led to the prediction of novel molecular states in these systems [71][72][73]. Related to this are the realisation of 'droplets' of both dipolar matter [74][75][76] and intriguingly, also light with a non-trivial angular momentum structure [77], as well as the prediction of soliton molecules in systems with nonlocal interactions [78].…”

Section: Soliton Molecules 41 Soliton Trimersmentioning

confidence: 99%

Coherent impurity transport in an attractive binary Bose–Einstein condensate

2019

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We study the dynamics of a soliton-impurity system modeled in terms of a binary Bose-Einstein condensate. This is achieved by 'switching off' one of the two self-interaction scattering lengths, giving a two component system where the second component is trapped entirely by the presence of the first component. It is shown that this system possesses rich dynamics, including the identification of unusual 'weak' dimers that appear close to the zero inter-component scattering length. It is further found that this system supports quasi-stable trimers in regimes where the equivalent single-component gas does not, which is attributed to the presence of the impurity atoms which can dynamically tunnel between the solitons, and maintain the required phase differences that support the trimer state. that the single component focussing nonlinear Schrödinger equation can possess chaotic solutions in the presence of an axial harmonic potential [29,30], as well as the observed interaction induced frequency shift of pairs of trapped bright solitons [31] in the experiment of [13]. Complementary to this, theoretical work has focussed on solitary waves in higher spin systems, revealing the existance of integrable points in the full parameter space of the spin-1 condensate, in the form of so-called 'polar' bright solitons [32,33]. Although solitons are usually studied as the solutions to one-dimensional nonlinear models, there have also been predictions of stable two-dimensional solitary wave solutions in dipolar Bose-Einstein condensates [34,35], where the additional nonlocal nonlinearity provides the stabilizing mechanism for these solitons. Very recently the Jones-Roberts soliton was realized experimentally, a true two-dimensional solitary wave structure [36].The realization of artificial electromagnetism with cold gases, and in particular spin-orbit coupling for Bose-Einstein condensates opens a novel route towards studying nonlinear wave structures. Here, the coupling of the condensates momentum to a quasi-spin leads to stripe-like soliton phases, related to the underlying immiscible phase of these systems [37,38]. Spin-orbit coupling forms a key ingredient in simulating more exotic scenarios, such as Dirac-like equations, where confined solutions have been predicted [39] that resemble their bright soliton cousins in single component condensates.Atomic condensates benefit from being exceptionally pure systems-this in turn allows one to investigate the effects of disorder and defects with an unprecedented level of control. The presence of impurities in ensembles of ultracold matter has led to predictions of impurity-molecules and lattices at the mean-field level [40], as well as the role of many-body correlations for a single impurity out-of-equilibrium [41]. Experimental work has studied the role that spin impurities have in the strongly correlated Tonks-Girardeau limit [42] and also magnetic spin models [43], which have also been the focus of subsequent theoretical investigations [44][45][46]. Complementary to this, recent exper...

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“…It involves a discrete random walk taken with steps that conserve particle number [40]. It has been used in several studies since [39,55,[57][58][59][60][61][62][63][64], and is also easily adapted to the GCE [39, 56].…”

Section: B Generation Of Ensemblesmentioning

confidence: 99%

Continuum of classical-field ensembles in Bose gases from canonical to grand canonical and the onset of their equivalence

2017

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The canonical and grand-canonical ensembles are two usual marginal cases for ultracold Bose gases, but real collections of experimental runs commonly have intermediate properties. Here we study the continuum of intermediate cases, and look into the appearance of ensemble equivalence as interaction rises for mesoscopic 1d systems. We demonstrate how at sufficient interaction strength the distributions of condensate and excited atoms become practically identical regardless of the ensemble used. Importantly, we find that features that are fragile in the ideal gas and appear only in a strict canonical ensemble can become robust in all ensembles when interactions become strong. As evidence, the steep cliff in the distribution of the number of excited atoms is preserved. To make this study, a straightforward approach for generating canonical and intermediate classical field ensembles using a modified stochastic Gross-Pitaevskii equation (SGPE) is developed.

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Dipolar dark solitons

Cited by 34 publications

References 33 publications

Controllable nonlocal interactions between dark solitons in dipolar condensates

Controllable nonlocal interactions between dark solitons in dipolar condensates

Coherent impurity transport in an attractive binary Bose–Einstein condensate

Continuum of classical-field ensembles in Bose gases from canonical to grand canonical and the onset of their equivalence

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