Treatment of backscattering in a gas of interacting fermions confined to a one-dimensional harmonic atom trap

TL;DR

This paper develops an exact many-body theory for spin-polarized interacting fermions in a one-dimensional harmonic trap, incorporating backscattering effects using bosonization, and compares results with numerical methods.

Contribution

It introduces a bosonization-based approach that includes backscattering in a trapped fermion system, extending the Luttinger model to more realistic confinement scenarios.

Findings

Backscattering generates one-particle potentials requiring diagonalization.

Interactions significantly modify particle densities and correlation functions.

The anomalous dimension aligns with Luttinger model predictions.

Abstract

An asymptotically exact many body theory for spin polarized interacting fermions in a one-dimensional harmonic atom trap is developed using the bosonization method and including backward scattering. In contrast to the Luttinger model, backscattering in the trap generates one-particle potentials which must be diagonalized simultaneously with the two-body interactions. Inclusion of backscattering becomes necessary because backscattering is the dominant interaction process between confined identical one-dimensional fermions. The bosonization method is applied to the calculation of one-particle matrix elements at zero temperature. A detailed discussion of the validity of the results from bosonization is given, including a comparison with direct numerical diagonalization in fermionic Hilbert space. A model for the interaction coefficients is developed along the lines of the Luttinger model with only one coupling constant $K$. With these results, particle densities, the Wigner function, and the central pair correlation function are calculated and displayed for large fermion numbers. It is shown how interactions modify these quantities. The anomalous dimension of the pair correlation function in the center of the trap is also discussed and found to be in accord with the Luttinger model.