Microwave preparation of two-dimensional fermionic spin mixtures

TL;DR

This paper introduces a microwave-based technique to prepare and image two-dimensional fermionic spin mixtures in optical lattices, optimizing transfer efficiency and minimizing atom loss for quantum-gas microscopy.

Contribution

It presents a novel method for spatially-selective microwave state transfer in a magnetic field gradient, enabling precise preparation of fermionic spin mixtures in 2D optical lattices.

Findings

High-efficiency adiabatic transfer pulses were developed.

Loss processes in spin mixtures were characterized.

Magnetic field gradients were minimized for homogeneous preparation.

Abstract

We present a method for preparing a single two-dimensional sample of a two-spin mixture of fermionic potassium in a single antinode of an optical lattice, in a quantum-gas microscope apparatus. Our technique relies on spatially-selective microwave transitions in a magnetic field gradient. Adiabatic transfer pulses were optimized for high efficiency and minimal atom loss and heating due to spin-changing collisions. We have measured the dynamics of those loss processes, which are more pronounced in the presence of a spin mixture. As the efficient preparation of atoms in a single antinode requires a homogeneous transverse magnetic field, we developed a method to image and minimize the magnetic field gradients in the focal plane of the microscope.