Collisionally Inhomogeneous Bose-Einstein Condensates with a Linear Interaction Gradient

Abstract

We study the evolution of a collisionally inhomogeneous matter wave in a spatial gradient of the interaction strength. Starting with a Bose-Einstein condensate with weak repulsive interactions in quasi-one-dimensional geometry, we monitor the evolution of a matter wave that simultaneously extends into spatial regions with attractive and repulsive interactions. We observe the formation and the decay of soliton-like density peaks, counter-propagating self-interfering wave packets, and the creation of cascades of solitons. The matter-wave dynamics is well reproduced in numerical simulations based on the nonpolynomial Schrödinger equation with three-body loss, allowing us to better understand the underlying behaviour based on a wavelet transformation. Our analysis provides new understanding of collapse processes for solitons, and opens interesting connections to other nonlinear instabilities.

Control of light-atom solitons and atomic transport by optical vortex beams propagating through a Bose-Einstein Condensate

“…As mentioned, we also employ a term L 3 |ψ| 4 ψ describing three-body loss (L 3 ≈ 10 −4 ) to arrive at an accurate description of the evolution of the BEC wave-function (matter-wave) in high-density regimes. The selected value of L 3 is in agreement with estimations for Caesium [21,22].…”

“…Typical scattering parameter values are given in Table I, using atomic parameters from [20]. For clarity we have chosen BEC parameters to match those found for a BEC of weakly repulsive Caesium atoms (a gg = 15.7a 0 , with a 0 the Bohr radius), giving β col = 3.5, but we emphasise that our analysis is applicable over a wide range of scattering lengths, accessible around the Feshbach resonance [21]. As mentioned, we also employ a term L 3 |ψ| 4 ψ describing three-body loss (L 3 ≈ 10 −4 ) to arrive at an accurate description of the evolution of the BEC wave-function (matter-wave) in high-density regimes.…”

Analogous Hawking radiation and quantum entanglement in two-component Bose-Einstein condensates: the gapped excitations

“…giving the step-like change of the sound speed across x = 0 while keeping U AB and Ω uniform across the condensate. The experimentally spatial variation of the interaction strengths is challenging but feasible [21][22][23]. Additionally, the external potential is chosen to satisfy [29,30]…”

“…More realistic transition can be considered in the waterfall configuration that relies on the full numerical studies to explore its physics. The experimentally spatial variation of the interaction strengths to fit into the configuration is challenged but feasible [21][22][23]. We first find the dispersion relation of the gapped excitations and identify the various modes in both supersonic and subsonic regimes.…”

Floquet solitons and dynamics of periodically driven matter waves with negative effective mass

“…1(a)]. A vertical magnetic field gradient is used to levitate the atoms against gravity, and a homogeneous magnetic field allows us to tune the s-wave scattering length a s with a magnetic Feshbach resonance [50,51]. To study weakly interacting atoms, we create a BEC with approximately 2 × 10 5 atoms in state F = 3, m F = 3 at a s = 210 a 0 .…”