Collective excitations of a Bose-Einstein condensate in an anharmonic trap

Abstract

We investigate the collective excitations of an one-dimensional Bose-Einstein condensate with repulsive interaction between atoms in a quadratic plus quartic trap. With using variational approaches, the coupled equations of motions for the center-of-mass coordinate of the condensate and its width are derived. Then, two low-energy excitation modes are obtained analytically. The frequency shift induced by the anharmonic distortion, and the collapse and revival of the collective excitations originated from the nonlinear coupling between the two modes, are discussed.

Interaction of a Bose–Einstein condensate and a superconductor via eddy currents

“…The interaction with the mirror BEC generates additional anharmonic terms to the harmonic trapping potential. The excitation of collective modes due to terms like x 3 , x 4 etc has been discussed previously [39][40][41][42]. The lowest order anharmonic term in (13) is of the form x 2 z 2 .…”

Dynamics of a Bose-Einstein Condensate on Changing Speeds of an Atomchip Trap Potential

“…Although collective excitation is not a new topic, the collective behaviors of the BEC on an atomchip is an interesting subject, for example, nonlinear dynamics [26,27], because the trap geometry can be changed with a high aspect ratio, wide range of time, and high anharmonicity, etc. We believe this data, along with further theoretical study, will help in dynamical control of ultracold atoms on an atomchip.…”

Rotating a Bose-Einstein condensate by shaking an anharmonic axisymmetric magnetic potential

“…2(c)]. The deviation for later time is understandable because the CM motion of the condensate having a finite spatial extent cannot be separable from its internal motion in the anharmonic potential [16][17][18]. In the following experiment, we employ the same driving procedure.…”

“…However, in a harmonic potential, which is typically used in experiments, the CM motion is completely decoupled from the internal motion of the condensate and it is impossible to transfer the angular momentum associated with the CM motion to the internal rotation of the condensate. The rotating method described in this work is based on the anharmonicity of a trapping potential which provides the coupling between the CM motion and the internal motion of a trapped * Electronic address: yishin@snu.ac.kr condensate [15][16][17][18]. We drive the condensate to circulate around the trap center by circularly shaking the trapping potential and observe that the circulating condensate relaxes into a rotating condensate with a vortex lattice.…”