# Transmon probe for quantum characteristics of magnons in antiferromagnets

## TL;DR

This paper explores a hybrid quantum system where a transmon qubit is coupled with magnons in antiferromagnetic materials, enabling the detection of quantum magnon properties through superconducting circuits.

## Contribution

It introduces a method to characterize quantum magnon modes and their entanglement in bipartite antiferromagnets using a transmon-based hybrid system.

## Key findings

- Magnon modes can be detected via transmon Rabi frequency.
- Quantum properties like nonlocality and entanglement are measurable.
- Magnetically invisible modes are characterized through this hybrid approach.

## Abstract

The detection of magnons and their quantum properties, especially in antiferromagnetic (AFM) materials, is a substantial step to realize many ambitious advances in the study of nanomagnetism and the development of energy efficient quantum technologies. The recent development of hybrid systems based on superconducting circuits provides the possibility of engineering quantum sensors that exploit different degrees of freedom. Here, we examine the magnon-photon-transmon hybridisation based on bipartite AFM materials, which gives rise to an effective coupling between a transmon qubit and magnons in a bipartite AFM. We demonstrate how magnetically invisible magnon modes, their chiralities and quantum properties such as nonlocality and two-mode magnon entanglement in bipartite AFMs can be characterized through the Rabi frequency of the superconducting transmon qubit.