Breakup and fragmentation of a rotating Bose-Einstein condensate*

The prime focus of research in the theoretical domain of rotating Bose-Einstein condensates is the emergence of quantum vortex states and condensed properties. However, this study looks at the other aspects by analyzing the impact of rotation on the ground state of interacting bosons trapped in anharmonic potentials. The multiconfigurational time-dependent Hartree method for bosons (MCTDHB), a well-known many-body method, is employed to explore the rotating condensate computed both at the mean-field and many-body levels. This study corroborates pathway of various degrees of fragmentation and subsequently breaking up of the ground state densities without ramping up any barrier in anharmonic potentials for strong rotation at the finite-particle limit. The breakup of density clouds is associated with angular momentum pumping in the condensate due to rotation. Interestingly, breaking of the densities computed at the mean-field and many-body levels depicts identical pattern both in the position and momentum space. The emergence of opposite anistropy in the variances despite having the same mean-field and many-body densities marks the presence of quantum fluctuations in the condensate. Finally, it is found that higher order symmetric systems, such as threefold and fourfold, in the rotating frame lead to an n-fold fragmented state while preserving the rotational symmetry of the condensate.