# Resource-aware System Architecture Model for Implementation of Quantum aided Byzantine Agreement on Quantum Repeater Networks

## TL;DR

This paper presents a resource-aware quantum system architecture for implementing Byzantine agreement on quantum repeater networks, optimizing circuit depth and qubit count to enable efficient distributed quantum algorithms.

## Contribution

It introduces a novel quantum architecture model with optimized circuits, reducing resource requirements for quantum Byzantine agreement on repeater networks.

## Key findings

- Quantum circuit depth reduced by 44%
- Number of qubits per node decreased by 20%
- Requires distributing 648 Bell pairs for a single algorithm execution

## Abstract

Quantum aided Byzantine agreement (QBA) is an important distributed quantum algorithm with unique features in comparison to classical deterministic and randomized algorithms, requiring only a constant expected number of rounds in addition to giving higher level of security. In this paper, we analyze details of the high level multi-party algorithm, and propose elements of the design for the quantum architecture and circuits required at each node to run the algorithm on a quantum repeater network. Our optimization techniques have reduced the quantum circuit depth by 44\% and the number of qubits in each node by 20\% for a minimum five-node setup compared to the design based on the standard arithmetic circuits. These improvements lead to an architecture with $KQ \approx 1.3 \times 10^{5}$ per node and error threshold $1.1 \times 10^{-6}$ for the total nodes in the network. The evaluation of the designed architecture shows that to execute the algorithm once on the minimum setup, we need to successfully distribute a total of 648 Bell pairs across the network, spread evenly between all pairs of nodes. This framework can be considered a starting point for establishing a road-map for light-weight demonstration of a distributed quantum application on quantum repeater networks.