Dynamics of neutral atoms in artificial magnetic field

• Cyclotron dynamic of neutral atoms in artificial gauge field (AGF) is presented.
• Rich and complex cyclotron trajectory of Bose gas exists, which depends on AGF.
• The proposed cyclotron dynamics can be realized more easily in the experiment.

Cyclotron dynamics of neutral atoms in a harmonic trap potential with artificial magnetic field is studied theoretically. The cyclotron orbit is obtained analytically and confirmed numerically. When the external harmonic potential is absent, artificial magnetic field can result in the singly periodic circular motion of Bose gas with the emergence of a Lorentz-like force, which is similar to particles with electric charge moving in a magnetic field. However, the coupling between artificial magnetic field and harmonic trap potential leads to rich and complex cyclotron trajectory, which depends on B2+1, where B   is the rescaled artificial magnetic field. When B2+1 is a rational number, the cyclotron orbit is multiply periodic and closed. However, when B2+1 is an irrational number, the cyclotron orbit is quasiperiodic, i.e., the cyclotron motion of Bose gas is limited in a annular region, and eventually, the motion is ergodic in this region. Furthermore, the cyclotron orbits also depend on the initial conditions of Bose gas. Thus, the cyclotron dynamics of Bose gas can be manipulated in a controllable way by changing the artificial magnetic field, harmonic trap potential and initial conditions. Our results provide a direct theoretical evidence for the cyclotron dynamics of neutral atoms in the artificial gauge field.