Dipolar condensates with tilted dipoles in a pancake-shaped confinement
arXiv:1608.06616 · doi:10.1103/PhysRevA.94.033633
Abstract
The effect of dipolar orientation with respect to the condensate plane on the mean-field dynamics of dipolar Bose-Einstein condensates in a pancake-shaped confinement is discussed. The stability of a quasi-two-dimensional condensate, with respect to the tilting angle, is found to be different from a two-dimensional layer of dipoles, indicating the relevance of the transverse extension while characterizing two-dimensional dipolar systems. An anisotropic excitation spectrum exhibiting a highly tunable, rotonlike minimum can arise entirely from the dipole-dipole interactions, by tilting the dipoles. At the magic angle and in the absence of contact interactions, the long-wavelength excitations are not phononlike and always unstable. The post-roton-instability dynamics, in contrast to phonon instability, in a uniform condensate, is featured by a transient, defect-free, stripe pattern, which eventually undergoes local collapses, and driving the condensate back into the stable regime can make them sustained for longer. Hopping between stripes has been observed before it melts into a uniform state in the presence of dissipation. Finally, we discuss a class of solutions, in which a quasi-two-dimensional condensate is self-trapped in one direction, as well as a regime of interaction parameters, including attractive short-range interactions, at which a two-dimensional anisotropic soliton can be stabilized, and we show that a chromium condensate with a relatively small number of atoms is well suited for this.
8 pages, 6 figures
References in corpus (13)
- Bose-Einstein condensation of chromium
- Bose-Einstein Condensation of Erbium
- Formation of bright matter-wave solitons during the collapse of Bose-Einstein condensates
- Stabilizing a purely dipolar quantum gas against collapse
- d-wave collapse and explosion of a dipolar Bose-Einstein condensate
- Radial and angular rotons in trapped dipolar gases
- Anisotropic solitons in dipolar Bose-Einstein Condensates
- Stability of quasi-two-dimensional Bose-Einstein condensates with dominant dipole-dipole interactions
- Quantum phases of a Two-Dimensional Dipolar Fermi Gas
- Thomas-Fermi versus one- and two-dimensional regimes of a trapped dipolar Bose-Einstein condensate
- Phase diagram of dipolar bosons in 2D with tilted polarization
- A general theory of flattened dipolar condensates
- Two-dimensional Bose gas of tilted dipoles: roton instability and condensate depletion