title: Spontaneous symmetry breaking of population in a nonadiabatically driven atomic trap: an Ising-class phase transition.
abstract: We have observed spontaneous symmetry breaking of the population of Brownian particles between two moving potentials in the spatiotemporally symmetric system. Cold atoms preferentially occupy one of the dynamic double-well potentials, produced in the parametrically driven dissipative magneto-optical trap far from equilibrium, above a critical number of atoms. We find that the population asymmetry, which may be interpreted as the biased Brownian motion, can be qualitatively described by the mean-field Ising-class phase transition. This in situ study may be useful for investigation of dynamic phase transition or temporal behavior of critical phenomena.
authors.affiliation: School of Physics, Seoul National University, Seoul 151-747, Korea.
authors.forename: Kihwan
authors.initials: K
authors.lastname: Kim
authors.forename: Myoung-Sun
authors.initials: MS
authors.lastname: Heo
authors.forename: Ki-Hwan
authors.initials: KH
authors.lastname: Lee
authors.forename: Kiyoub
authors.initials: K
authors.lastname: Jang
authors.forename: Heung-Ryoul
authors.initials: HR
authors.lastname: Noh
authors.forename: Doochul
authors.initials: D
authors.lastname: Kim
authors.forename: Wonho
authors.initials: W
authors.lastname: Jhe