Loading and detecting a three-dimensional Fermi gas in one-dimensional optical superlattice

TL;DR

This paper explores how to load, detect, and understand the dynamics of a three-dimensional Fermi gas in a one-dimensional optical superlattice, highlighting the effects of trapping potentials and ramp procedures.

Contribution

It provides a detailed numerical analysis of loading and detection procedures, and investigates relaxation dynamics after potential changes in a non-interacting fermionic system.

Findings

Differences in excitation evolution between homogeneous and trapped systems.

Bimodal distribution of excitations after slow potential change.

Strong dependence of measurement outcomes on ramp procedures.

Abstract

We investigate the procedures of loading and detecting three-dimensional fermionic quantum gases in a one-dimensional optical superlattice potential subjected to a trapping potential. Additionally, we consider the relaxation dynamics after a sudden change of the superlattice potential. We numerically simulate the time-dependent evolution of the continuous system using exact diagonalization of non-interacting fermions. During the loading procedure we analyze the occupation of the instantaneous energy levels and compare the situation in a homogeneous system with the trapped one. Strong differences are found in particular in the evolution of excitations which we trace back to the distinct global density distribution. Starting from an imbalanced state in the superlattice potential, we consider the relaxation dynamics of fermions after a slow change of the superlattice potential and find a bimodule distribution of excitations. To be able to compare with the experimental results we also simulate the measurement sequence of the even and odd local density and find a strong dependence of the outcome on the actual ramp procedure. We suggest how the loading and detecting procedure can be optimized.