From Few to Many: Observing the Formation of a Fermi Sea One Atom at a Time

Abstract

Not Very Many In physics, the behavior of a system sometimes becomes easier to grasp when the number of particles is large and statistics begin to matter, but knowing how large the system needs to be for that to happen is a challenging computational problem. Wenz et al. (p. 457 ) used a one-dimensional trapped gas of 6 Li atoms to study this crossover from few to many. To simplify the problem, they worked with one “impurity” atom that was in a state unlike the other—“majority”—atoms. For weak and intermediate interactions, the system approached the many-body limit with as few as four majority atoms.