Quantum-information-theoretical measures to distinguish fermionized bosons from noninteracting fermions

Abstract

We study the dynamical fermionization of strongly interacting one-dimensional bosons in Tonks-Girardeau limit by solving the time-dependent many-boson Schr\"odinger equation numerically exactly. We establish that the one-body momentum distribution approaches the ideal Fermi gas distribution at the time of dynamical fermionization. The analysis is further complemented by the measures on the two-body level. The dynamical fermionization in the two-body level should be inferred as the presence of a distinct correlation hole along the diagonal of two-body correlation. Investigation of two-body momentum distribution for the strongly interacting bosons clearly exhibits a pattern along the diagonal which is not extinguished at the time of fermionization. Two-body local and nonlocal correlation also clearly distinguish the fermionized bosons from noninteracting fermions. The magnitude of distinguishablity between the two systems is further discussed employing suitable measures of information theory, i.e., the well-known Kullback-Leibler relative entropy and the Jensen-Shannon divergence entropy. We also observe very rich structure in the higher-body density for strongly correlated bosons, whereas noninteracting fermions do not possess any higher-order correlation beyond two-body.