Bifurcations and exceptional points in dipolar Bose-Einstein condensates

Jörg Main

Universität Stuttgart, Theoretische Physik 1, Stuttgart, Germany

We demonstrate that the method of coupled Gaussian wave packets is a full-fledged alternative to direct numerical solutions of the Gross-Pitaevskii equation of dipolar condensates. Gaussian wave packets are capable of producing both stable and unstable stationary solutions and thus of giving access to yet unexplored regions of the space of solutions of the Gross-Pitaevskii equation. We apply the method to clarify the theoretical nature of the collapse mechanism of blood-cell-shaped dipolar condensates: On the route to collapse the condensate passes through a pitchfork bifurcation, where the ground state itself turns unstable, before it finally vanishes in a tangent bifurcation. The question whether or not the bifurcation points are exceptional points is addressed.

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