Stability and structure of an anisotropically trapped dipolar Bose-Einstein condensate: angular and linear rotons

Abstract

We study theoretically Bose-Einstein condensates with polarized dipolar interactions in anisotropic traps. We map the parameter space by varying the trap frequencies and dipolar interaction strengths and find an irregular-shaped region of parameter space in which density-oscillating condensate states occur, with maximum density away from the trap center. These density-oscillating states may be biconcave (red-blood-cell-shaped), or have two or four peaks. For all trap frequencies, the condensate becomes unstable to collapse for sufficiently large dipole interaction strength. The collapse coincides with the softening of an elementary excitation. When the condensate mode is density-oscillating, the character of the softening excitation is related to the structure of the condensate. We classify these excitations by linear and angular characteristics. We also find excited solutions to the Gross-Pitaevskii equation, which are always unstable.

9 pages, 7 figures; modified in response to referee comments

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Cited by in corpus (4)

• A general theory of flattened dipolar condensates
• A magic tilt angle for stabilizing two-dimensional solitons by dipole-dipole interactions
• Thermally activated local collapse of a flattened dipolar condensate
• Effect of optical lattice potentials on the vortices in rotating dipolar Bose-Einstein condensates