Decoherence and dissociation of ⁷Li matter-wave breather

Breathers, i.e. higher-order solitons, can be obtained from fundamental solitons by quenching the interaction strength in the nonlinear Schrodinger equation (NLSE). A Bose-Einstein condensate (BEC) confined to a quasi-one dimensional waveguide is a valuable platform to study soliton physics, primarily because of the ability to tune interactions via a Feshbach resonance. In the mean-field (MF) limit, one-dimensional breathers are expected to show a pure periodic oscillation without decay or dissociation due to the integrability of the NLSE. Nevertheless, quantum effects are predicted to cause breathers to undergo a frequency drift of their oscillation [1] and to dissociate into its constituent solitons [2] even at meso- or macroscopic scale. Even in the MF limit, however, systematic effects such as particle loss can produce loss of coherence. In this experiment, matter-wave breathers from a BEC of ⁷Li are prepared in an optical dipole trap [3]. The axial trap confinement is relaxed sufficiently to prepare the system in the quasi-one dimensional regime. We report the experimental observation of the decoherence and dissociation of breathers at a rate that depends on several parameters, including the number of atoms and the proximity to the collapse threshold. These measurements should help to resolve the role played by quantum effects in our experiment.

 

[1] B. Opanchuk and P.D. Drummond, Phys. Rev. A. 96, 053628 (2017)

[2] V.A. Yurovsky, B.A. Malomed, R.G. Hulet, and M. Olshanii, Phys. Rev. Lett. 119, 220401 (2017); O.V. Marchukov et al., Phys. Rev. Lett. 125, 050405 (2020)

[3] D. Luo et al., Phys. Rev. Lett. 125, 183902 (2020)