We show by means of an exact numerical approach that the momentum distribution of a free expanding gas of hard-core bosons on a one-dimensional lattice approaches that of noninteracting fermions, acquiring a Fermi edge. Yet there is a power-law decay of the one-particle density matrix ρx∼1/x, as usual for hard-core bosons in the ground state, which accounts for a large occupation of the lowest natural orbitals for all expansion times. The fermionization of the momentum distribution function, which is not observed in equilibrium, is analyzed in detail.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)