Production of strongly bound K39 bright solitons

Abstract

We report on the production of 39 K matter-wave bright solitons, i.e., 1D matter-waves that propagate without dispersion thanks to attractive interactions. The volume of the soliton is studied as a function of the scattering length through three-body losses, revealing peak densities as high as ∼ 5 × 10 20 m −3 . Our solitons, close to the collapse threshold, are strongly bound and will find applications in fundamental physics and atom interferometry.PACS numbers: 03.75. Lm, Solitons are one-dimensional wave-packets that propagate with neither change of shape nor loss of energy. They are a consequence of non-linearities that balance wave-packet spreading due to dispersion. They appear in numerous physical systems such as water waves, optical fibers, plasmas, acoustic waves or even in energy propagation along proteins [1]. Solitons are also observed in ultracold quantum gases [2][3][4][5][6]. In this context, matterwave bright solitons are Bose-Einstein condensates that remain bound thanks to mean-field attractive interactions in a one dimensional geometry [2,3].Matter-wave bright solitons are predicted to be a great tool to locally probe rapidly varying forces for example close to a surface [7,8], or probe (surface) bound states [7,9] which do not appear in linear scattering. For example, the small size of bright solitons has been used in the measurement of quantum reflection from a barrier [10,11]. Because of their dispersion-free propagation, bright solitons are also believed to be good candidates for performing very long time atom interferometry measurements [12] although interactions may cause additional phase shifts [13][14][15][16]. Recently, an experiment demonstrated an increased visibility for a soliton atomic interferometer as compared to its non interacting counterpart [17]. The interactions in solitons can also lead to squeezed or entangled states, which could improve the sensitivity of interferometric measurements beyond the shot noise limit [18][19][20][21][22][23][24]. In some cases, the formation of mesoscopic Schrödinger cat states or NOON states is predicted [25][26][27]. A problem in using these states is losses, such as three-body collisions, which are an intrinsic source of decoherence. They can also induce unusual soliton center of mass dynamics [28].Experiments producing and studying matter-wave bright solitons, despite their interest in both applied and fundamental physics, have remained scarce. In fact, only two elements have been turned into bright solitons, 7 Li [2, 3, 29, 30] and 85 Rb [10,31]. In this paper, we describe the production of 39 K solitons in the |F = 1, m F = −1 state using the Feshbach resonance at 561 G [32] and its associated zero-crossing of the scattering length at 504.4 G (see figure 1). We have optimized the setup in order to produce strongly bound solitons, i.e., solitons with a large negative interaction energy. We thus pro- The evaporation to Bose-Einstein condensation takes place at 550 G (red bullet). The magnetic field is then ramped in two steps to 507 G (vi...

Cesium bright matter-wave solitons and soliton trains

“…Previously, bright solitons have been created in 7 Li [8,9,24], 85 Rb [18,25,26] and 39 K [27], but this is, to our knowledge, the first demonstration of 133 Cs solitons.…”

Delta-Bose gas on a half-line and the Kardar–Parisi–Zhang equation: boundary bound states and unbinding transitions

“…The dynamical correlations have been studied in [92,93]. It is an interesting strongly correlated model [94] with nontrivial bound states, also observed in experiments [95,96]. Recently its non-equilibrium properties have received a large attention, in particular after a quantum quench [97][98][99].…”

Energy of N two-dimensional bosons with zero-range interactions

“…This defines the window of parameters where the droplet is observable; one can see that N is not necessarily very small. Given extremely low values of a routinely produced in experiments (see, for example, [19][20][21]), it is realistic to observe droplets of a few tens of particles. The preparation of a droplet can be realized, for example, by simultaneously switching off of the radial confinement and sweeping the scattering length from a positive to negative value near a zero crossing.…”

“…Finally, we mention that our method can be extended to bosonic mixtures with different masses. 9 1.6508(4)×10 7 21 3.577(2)×10 18 10 1.4905(2)×10 8 22 3.108(4)×10 19 11 1.3345(2)×10 9 23 2.694(5)×10 20 12 1.1873(4)×10 10 24 2.332(4)×10 21 13 1.0508(3)×10 11 25 2.018(4)×10 22 14 9.2596(9)×10 11 26 1.748(4)×10 23…”