# Distributed multi-parameter quantum metrology with a superconducting quantum network

## TL;DR

This paper demonstrates a scalable method for measuring multiple physical parameters across a quantum network using superconducting technology.

## Contribution

The work introduces a modular superconducting quantum network for distributed multiparameter quantum metrology with improved precision.

## Key findings

- The authors achieved a 13.72 dB precision improvement in estimating a remote vector field.
- They realized a 3.44 dB gain in estimating vector field gradients across separated nodes.

## Abstract

Quantum metrology has emerged as a powerful tool for timekeeping, field sensing, and precision measurements in fundamental physics. With the advent of distributed quantum metrology, its capabilities have extended to probing spatially distributed parameters across networked quantum systems. However, scalable implementations of distributed quantum metrology with multiparameter estimation remain limited, particularly due to the challenges of generating and distributing entanglement across a quantum network and dealing with incompatibilities in multiparameter quantum metrology. Here we demonstrate distributed multiparameter quantum metrology on a modular superconducting quantum network with low-loss microwave interconnects, a platform that uniquely combines fast gate operations, adaptive control, and deterministic non-local entanglement generation. Using a control-enhanced sequential protocol, we estimate all three components of a remote vector field, achieving up to 13.72 dB improvement in precision over the individual strategy. We further perform direct estimation of vector field gradients along two directions across spatially separated nodes, realizing a 3.44 dB gain over local entanglement strategies. These results establish superconducting quantum networks as a competitive and reconfigurable platform for scalable multiparameter distributed quantum metrology.

Distributed multiparameter quantum metrology allows to probe multiple spatially distributed parameters across networked quantum systems. Here, the authors demonstrate distributed multiparameter quantum metrology in a modular superconducting quantum processor network.