# Implementation of a Distributed Coherent Quantum Observer

## TL;DR

This paper proposes a practical implementation of a distributed quantum observer using optical components, demonstrating convergence to a consensus estimate of a quantum system's output.

## Contribution

It introduces a modified observer design and an experimental setup with optical cavities and amplifiers for implementing distributed quantum observation.

## Key findings

- Observer converges to a consensus in a time-averaged sense
- Implementation using non-degenerate parametric amplifier and optical cavities
- Demonstrates feasibility of distributed quantum observation

## Abstract

This paper considers the problem of implementing a previously proposed distributed direct coupling quantum observer for a closed linear quantum system. By modifying the form of the previously proposed observer, the paper proposes a possible experimental implementation of the observer plant system using a non-degenerate parametric amplifier and a chain of optical cavities which are coupled together via optical interconnections. It is shown that the distributed observer converges to a consensus in a time averaged sense in which an output of each element of the observer estimates the specified output of the quantum plant.