Switching and phase transitions in a parametrically-excited cold atom trap.

Yao-Hua, Chen, Wei Wei +6 more

Xiong-Jun Liu, Xin Liu, Congjun Wu +1 more

Ji Hyun Kim

Kihwan Kim, Myoung-Sun Heo, Ki-Hwan Lee +4 more

We have investigated the noise-induced transition of cold atoms between double or triple phase-space attractors that are produced in the parametrically driven magneto-optical trap. The transition rates between two dynamic attractors, directly measured for various modulation frequencies and amplitudes, are in good agreement with calculations from the dynamic version of Kramers' theory and Monte Carlo simulations. For the triple attractors, the transition rates are measured indirectly through the steady-state population and the results are also in agreement with simulations. Our experiment may be useful for study of nonlinear dynamic problems involving transitions between states far from equilibrium.

P Insang, Nuttida Kaewart, Nithiwadee Thaicharoen +1 more

Abstract Temperature estimation of cold atoms in sub-Doppler to Doppler temperatures is crucial for determining various aspects such as diffusion, compressibility, trap stability, phase transition, and many-body collision dynamics. In this temperature regime, cold atoms are typically confined in a magnetic trap for further investigation. In some cases, temperature estimation from a typical time-of-flight method is not applicable due to the long switch-off time of the magnetic trap. In this work, we employ a non-invasive number counting method without having to turn off the magnetic field to estimate the temperature. We explore various number count conditions for a temperature range between 20 µK to 100 µK in such a way that the trace of number counts can be used as a reference to estimate the temperature of cold atoms in a magnetic trap.

Ji-Hyoun Kim, Yong Hee Kim, Geol Moon +2 more