DIPOLAR CONDENSATES CONFINED IN A TOROIDAL TRAP

M. GUILLEUMAS; M. ABAD; R. MAYOL; M. PI; D. M. JEZEK

Foz do Iguazu

Workshop; The nineteenth annual International Laser Physics Workshop (LPHYS'10); 2010

A Bose-Einstein condensate of 52Cr atoms is a very suitable system for studying the effects of dipolar interactions due to their large magnetic dipole moment. In contrast to s-wave interactions, dipole-dipole interactions are long range and anisotropic. These main features lead to interesting new physics in the field of Bose-Einstein condensation[1]. The experimental realization of dipolar condensates in harmonic traps[2, 3] opens the possibility of studying them in more complex confining potentials, such as toroidal traps. We study a Bose-Einstein condensate of 52Cr atoms confined in a toroidal trap with a variable strength of s-wave contact interactions. We consider the magnetization to be perpendicular to the trap symmetry axis and investigate the effects induced by the anisotropic nature of the dipolar interaction. When the trap is purely harmonic and pancake-shaped, it is possible to tune the geometry of the system just by varying the scattering length: for large values, the system shows mainly a pancake-shaped geometry, while for small scattering lengths it can reach a cigar-shaped configuration. The anisotropic character of the dipolar interaction can be further enhanced in a toroidal trap: for small values of the scattering length the density presents an azimuthal dependence along the magnetization direction. Moreover, below a certain value, the system undergoes a dipolar-induced symmetry breaking phenomenon resembling an origin-displaced cigar-shaped condensate. We also study vortex states[4].References[1] T. Lahaye, C. Menotti, L. Santos, M. Lewenstein, and T. Pfau, Rep. Prog. Phys. 72, 126401 (2009).[2] A. Griesmaier, J. Werner, S. Hensler, J. Stuhler, and T. Pfau, Phys. Rev. Lett. 94, 160401 (2005).[3] Q. Beaufils, R. Chicireanu, T. Zanon, B. Laburthe-Tolra, E. Maréchal, L. Vernac, J.-C. Keller, and O. Gorceix, Phys. Rev. A 77, 061601(R) (2008).[4] M. Abad, M. Guilleumas, R. Mayol, M. Pi, and D. Jezek, Phys. Rev. A 79, 063622 (2009).