Momentum distribution of He-3 in one dimension

TL;DR

This paper presents numerical results for the momentum distribution of helium-3 in one dimension, highlighting the effects of quantum statistics and polarization on the system's properties.

Contribution

It provides the first exact numerical calculations of the one-particle density matrix and momentum distribution for 1D helium-3 using the Worm Algorithm.

Findings

Quantum statistics effects are observable in the fully polarized system.

Effects are suppressed in the unpolarized system, atoms behave as distinguishable.

Results demonstrate the applicability of the Worm Algorithm to fermionic systems.

Abstract

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.