Momentum distribution of He-3 in one dimension

The one-particle density matrix of a one-dimensional system of fermions featuring a hard-core repulsive interaction at short distances can be computed (numerically) exactly by means of the continuous-space Worm Algorithm, without any sign instability. We present here results for this quantity, and the related momentum distribution, for a helium-three fluid. It is shown that effects of quantum statistics are observable in the fully polarized system, but are suppressed in the unpolarized one, atoms being essentially distinguishable in the latter case.