Reaching Agreement in Quantum Hybrid Networks

Area of Science:

• Quantum Information Science
• Network Theory
• Control Systems

Background:

• Quantum hybrid networks integrate quantum and classical components.
• Achieving consensus in quantum networks is crucial for distributed quantum computing and secure communication.
• Existing methods for network control can face computational and communication challenges.

Purpose of the Study:

• To propose a quantum hybrid network model for achieving consensus among qubits.
• To develop a distributed algorithm for efficient consensus in quantum networks.
• To analyze the performance of the proposed consensus protocol.

Main Methods:

• A quantum hybrid network model with nodes holding qubits.
• Application of projective measurements as control mechanisms.
• Exchange of measurement results via classical communication channels.
• Development of a distributed Pairwise Qubit Projection (PQP) algorithm.

Main Results:

• The Pairwise Qubit Projection (PQP) algorithm drives qubit states to consensus almost surely.
• Expected qubit density operators converge to the average of the network's initial values.
• The PQP algorithm overcomes computational and communication obstacles of centralized solutions.

Conclusions:

• The proposed PQP algorithm offers an effective distributed strategy for achieving consensus in quantum hybrid networks.
• The model captures the quantum-operation/classical-communication nature of hybrid systems.
• This work contributes to the advancement of distributed quantum information processing.