Dilute-gas Bose-Einstein condensates are an exceptionally versatile testbed for the investigation of novel solitonic structures. While matter-wave solitons in one-and two-component systems have been the focus of intense research efforts, an extension to three components has never been attempted in experiments, to the best of our knowledge. Here, we experimentally demonstrate the existence of robust dark-bright-bright (DBB) and dark-dark-bright (DDB) solitons in a spinor F = 1 condensate. We observe lifetimes on the order of hundreds of milliseconds for these structures. Our theoretical analysis, based on a multiscale expansion method, shows that small-amplitude solitons of these types obey universal long-short wave resonant interaction models, namely Yajima-Oikawa systems. Our experimental and analytical findings are corroborated by direct numerical simulations highlighting the persistence of, e.g., the DBB states, as well as their robust oscillations in the trap.PACS numbers: 03.75. Mn, 03.75.Lm Solitons are localized waves propagating undistorted in nonlinear dispersive media. They play a key role in numerous physical contexts [1]. Among the various systems that support solitons, dilute-gas Bose-Einstein condensates (BECs) [2,3] provide a particularly versatile testbed for the investigation of solitonic structures [4][5][6]. In single-component BECs, solitons have been observed either as robust localized pulses (bright solitons) [7][8][9][10][11] or density dips in a background matter wave (dark solitons) [12][13][14][15][16][17][18][19][20][21], typically in BECs with attractive or repulsive interatomic interactions, respectively. Extending such studies to two-component BECs has led to rich additional dynamics. Solitons have been observed in binary mixtures of different spin states of the same atomic species, so-called pseudo-spinor BECs [22,23]. In particular, darkbright (DB) [24][25][26][27][28], and related SO(2) rotated states in the form of dark-dark solitons [29,30], have experimentally been created in binary 87 Rb BECs. Interestingly, although such BEC mixtures feature repulsive intra-and inter-component interactions, bright solitons do emerge due to an effective potential well created by the dark soliton through the intercomponent interaction [31]. Such mixed soliton states have been proposed for potential applications. Indeed, in the context of optics where these structures were pioneered [32,33], the dark soliton component was proposed to act as an adjustable waveguide for weak bright solitons [34]. In multicomponent BECs, compound solitons of the mixed type could also be used for all-matter-wave waveguiding, with the dark soliton building an effective conduit for the bright one, similar to all-optical waveguiding in optics [35]. Apart from pseudospinor BECs, such mixed soliton states have also been predicted to occur in genuinely spinorial BECs, composed of different Zeeman sub-levels of the same hyperfine state [36][37][38]. Indeed, pertinent works [39,40] have studied the existence and dynamic...
The Josephson effect is a prominent phenomenon of quantum supercurrents that has been widely studied in superconductors and superfluids. Typical Josephson junctions consist of two realspace superconductors (superfluids) coupled through a weak tunneling barrier. Here we propose a momentum-space Josephson junction in a spin-orbit coupled Bose-Einstein condensate, where states with two different momenta are coupled through Raman-assisted tunneling. We show that Josephson currents can be induced not only by applying the equivalent of "voltages", but also by tuning tunneling phases. Such tunneling-phase-driven Josephson junctions in momentum space are characterized through both full mean field analysis and a concise two-level model, demonstrating the important role of interactions between atoms. Our scheme provides a platform for experimentally realizing momentum-space Josephson junctions and exploring their applications in quantummechanical circuits. arXiv:1710.06369v2 [cond-mat.quant-gas]
In the past few decades, the search for supersolid-like phases has attracted great attention in condensed matter and ultracold atom communities. Here we experimentally demonstrate a route for realizing a superfluid stripe-phase in a spin-orbit coupled Bose-Einstein condensate by employing a weak optical lattice to induce momentum-space hopping between two spin-orbit band minima. We characterize the striped ground state as a function of lattice coupling strength and spin-orbit detuning and find good agreement with mean-field simulations. We observe coherent Rabi oscillations in momentum space between two band minima and demonstrate a long lifetime of the ground state. Our work offers an exciting new and stable experimental platform for exploring superfluid stripe-phases and their exotic excitations, which may shed light on the properties of supersolid-like states.Introduction. Supersolids are an exotic phase of matter which simultaneously possess the crystalline properties of a solid and the unique flow properties of a superfluid [1]. Such simultaneous breaking of continuous translational symmetry and U(1) gauge symmetry was first predicted for solid helium [2,3], but convincing evidence of a supersolid state in this system has remained elusive [4]. In recent years, the experimental realization of spin-orbit coupling (SOC) in ultracold atomic gases [5][6][7][8][9][10][11][12][13][14][15][16][17] has opened a new pathway for demonstrating long-sought supersolidlike states [18][19][20][21][22][23][24][25][26][27][28][29][30].The lowest energy band in the SOC dispersion is characterized by two local minima at distinct momenta [5]. For a narrow range of system parameters, mean-field interactions within a Bose-Einstein condensate (BEC) favor a ground state which is composed of a coherent superposition of two plane-wave states at the dispersion minima [22]. This superposition leads to density modulations in real space, or stripes, therefore breaking translational symmetry while maintaining the superfluid phase correlation of a BEC. Such a stripe-phase was initially proposed for SOC BECs where the pseudospins are defined by two atomic hyperfine states [5]. While great experimental progress has been made in exploring the rich physics of such SOC systems, a ground state superfluid stripe-phase has not been observed in this context. The necessary parameter space is prohibitively sensitive to magnetic field fluctuations and the resulting density modulation is weak. However, recent works have attempted to sidestep these difficulties in creative ways, leading to experimental observations of some signatures of superfluid stripe phases in different systems [31][32][33][34].Despite these significant advances, the quest for a robust and long-lived platform for the experimental investigations of stripe-phase properties remains. In this Letter, we show that the superposition of two local band minima to form a supersolid-like ground state can be robustly achieved by means other than atomic interactions.Specifically, we engineer momen...
Double-well systems loaded with one, two, or many quantum particles give rise to intriguing dynamics, ranging from Josephson oscillation to self-trapping. This work presents theoretical and experimental results for two distinct double-well systems, both created using dilute rubidium Bose-Einstein condensates with particular emphasis placed on the role of interaction in the systems. The first is realized by creating an effective two-level system through Raman coupling of hyperfine states. The second is an effective two-level system in momentum space generated through the coupling by an optical lattice. Even though the non-interacting systems can, for a wide parameter range, be described by the same model Hamiltonian, the dynamics for these two realizations differ in the presence of interactions. The difference is attributed to scattering diagrams that contribute in the lattice coupled system but vanish in the Raman coupled system. The internal dynamics of the Bose-Einstein condensates for both coupling scenarios is probed through a Ramsey-type interference pulse sequence, which constitutes a key building block of atom interferometers. These results have important implications in a variety of contexts including lattice calibration experiments and momentum space lattices used for quantum analog simulations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.