# Detecting Spin Transport in Quantum Magnets with Photons

## TL;DR

This paper introduces a minimally invasive microwave photon-based method to detect spin conductance and noise in quantum magnets, enabling detailed analysis of spin transport properties.

## Contribution

It proposes a novel technique using microwave resonators coupled to quantum magnets to measure spin conductance and noise through photon detection.

## Key findings

- The method can extract both dc and finite frequency spin current noise.
- It allows measurement of junction spin conductance by temperature variation.
- The technique is minimally invasive and compatible with existing microwave technology.

## Abstract

A minimally invasive technique is proposed for detecting the differential spin conductance and spin current noise across a junction between two quantum magnets using a high-quality microwave resonator coupled to a transmission line which is impedance matched to a photon detector downstream. Photons in the microwave resonator couple inductively to the spins in the spin subsystem, and the noise in the junction spin current imprints itself into the output photons propagating along the transmission line. The technique is capable of extracting both the dc and finite frequency noise via the output photon flux and of measuring the junction spin conductance by driving the electromagnetic environment into a different temperature regime.