Observation of dynamical fermionization

Abstract

Capturing the transformation Quantum statistics dictates the behavior of identical particles in the quantum world: Bosons like to congregate, whereas fermions avoid one another. However, strong interactions can cause a string of bosons to behave like fermions. This so-called fermionization phenomenon has been studied in equilibrium. Wilson et al. instead focused on dynamical fermionization in a nonequilibrium system consisting of tubes of strongly interacting bosonic rubidium atoms. After letting the tubes expand in the axial direction, the researchers monitored the momentum distribution of the atoms and found that it evolved from bosonic-like to fermionic-like. Science , this issue p. 1461