Local Magnetometry from Measurement-Induced Dissipation

TL;DR

This paper demonstrates that measurement-induced dissipation in a primary qubit coupled to a spin lattice can reveal local magnetic order, including antiferromagnetic and altermagnetic textures, without relying on net magnetization.

Contribution

The authors introduce a protocol using measurement-induced steady states of a qubit to detect local magnetic order, providing a new microscopic approach beyond traditional macroscopic magnetization methods.

Findings

Steady states encode local exchange fields in a measurable observable.

Numerical simulations show lattice-scale resolution of magnetic textures.

Robustness against short-correlated noise is demonstrated.

Abstract

Magnetic phases are commonly identified through macroscopic magnetization, yet many ordered states, including antiferromagnets and altermagnets, possess a vanishing net moment despite distinct local spin structure. We show that such an order can be accessed through the measurement-induced steady state of a single primary qubit locally coupled to a spin lattice. Using a controlled primary-ancillary qubit protocol, we derive analytically that the steady state \emph{encodes} a locally weighted exchange field in a signed observable that is linear in the weak-coupling regime. Numerical simulations demonstrate lattice-scale resolution of antiferromagnetic and altermagnetic textures and robustness against short-correlated noise. Our results establish measurement-induced dissipation as a resource for detecting magnetic order through microscopic structure rather than through global moments.