Observation of Parametric Resonance Phenomenon in a Cold Cesium Atoms
Dooyoung Kim, Jaeuk Baek, Minsu Kim +7 more
Abstract We report the first observation of motional excitation induced by parametric resonance of cold $^{133}$Cs atoms in a dual-species magneto-optical trap (MOT) simultaneously trapping 133 Cs and 85 Rb atoms. By modulating the cooling laser’s intensity at approximately twice the resonant frequency of the trap, the atoms inside the trap separate into two atomic clouds, oscillating with a π phase difference due to the trap potential’s nonlinearity, resulting in a finite oscillation length. This behavior reflects general nonlinear dynamics and is described as a Hopf bifurcation or limit cycle motion. The measured oscillation amplitude was compared with theoretical calculations derived from simple Doppler cooling theory, changing modulation amplitude, magnetic field gradient, and saturation parameter. In addition, we investigate the noise-induced switching dynamics by measuring the temporal evolution of atomic populations localized in each of the two attractors under resonant symmetry lifting induced by an effective bias field. Notably, this dual-species MOT system is expected to provide a new platform for studying nonlinear and nonequilibrium dynamics between cold rubidium and cesium atomic ensembles. PACS numbers: 37.10.Vz, 37.10.De, 37.10.Gh
•Jun 11, 2026•0 citations