Instability domain of Bose–Einstein condensates with quantum fluctuations and three-body interactions

Through a Gross–Pitaevskii equation comprising cubic, quartic, residual, and quintic nonlinearities, we examine the modulational instability (MI) of Bose–Einstein condensates at higher densities in the presence of quantum fluctuations. We obtain an explicit time-dependent criteria for the MI and the instability domains of the condensates. Solitons are generated by suitably exciting the MI, and their stability is analyzed. We find that quantum fluctuations can completely change the instability of condensates by reversing the nature of the effective two-body interactions. The interplay between three-body interactions and quantum fluctuations is shown. Numerical simulations performed agree with analytical predictions.

► A Gross–Pitaevskii equation with cubic, quartic, residual, and quintic terms is used.
► We find the stability domain and time-dependent criteria for modulational instability.
► We analyze the stability of solitons generated through modulational instability.
► Quantum fluctuations reverse the effect of two-body interactions in a condensate.
► Three-body interactions suppress the instability caused by quantum fluctuations.