# Quantized conductance through a spin-selective atomic point contact

## TL;DR

This paper demonstrates a microscopic spin filter for cold fermionic atoms using a quantum point contact, achieving spin-polarized currents with conductance quantization and exploring interaction effects.

## Contribution

It introduces a novel optical tweezer technique to create a spin filter in cold atoms, enabling studies of spin-splitting and interactions in quantum transport.

## Key findings

- Achieved fully spin-polarized currents in a cold atom QPC
- Observed renormalization of Zeeman shift due to interactions
- Maintained conductance quantization with spin filtering

## Abstract

We implement a microscopic spin filter for cold fermionic atoms in a quantum point contact (QPC) and create fully spin-polarized currents while retaining conductance quantization. Key to our scheme is a near-resonant optical tweezer inducing a large effective Zeeman shift inside the QPC while its local character limits dissipation. We observe a renormalization of this shift due to interactions of a few atoms in the QPC. Our work represents the analog of an actual spintronic device and paves the way to studying the interplay between spin-splitting and interactions far from equilibrium.