A Quantum Federated Learning Framework for Classical Clients

TL;DR

This paper introduces a quantum federated learning framework for classical clients that leverages server-side quantum capabilities and shadow tomography, enabling collaborative quantum model training without client quantum resources.

Contribution

The paper proposes CC-QFL, a novel framework allowing classical clients to participate in quantum federated learning without quantum hardware, using server-side quantum computation and shadow tomography.

Findings

Effective training of QML models with classical clients demonstrated.

Framework suitable for scenarios with limited quantum resources.

Numerical simulations validate the approach on MNIST dataset.

Abstract

Quantum Federated Learning (QFL) enables collaborative training of a Quantum Machine Learning (QML) model among multiple clients possessing quantum computing capabilities, without the need to share their respective local data. However, the limited availability of quantum computing resources poses a challenge for each client to acquire quantum computing capabilities. This raises a natural question: Can quantum computing capabilities be deployed on the server instead? In this paper, we propose a QFL framework specifically designed for classical clients, referred to as CC-QFL, in response to this question. In each iteration, the collaborative training of the QML model is assisted by the shadow tomography technique, eliminating the need for quantum computing capabilities of clients. Specifically, the server constructs a classical representation of the QML model and transmits it to the clients. The clients encode their local data onto observables and use this classical representation to calculate local gradients. These local gradients are then utilized to update the parameters of the QML model. We evaluate the effectiveness of our framework through extensive numerical simulations using handwritten digit images from the MNIST dataset. Our framework provides valuable insights into QFL, particularly in scenarios where quantum computing resources are scarce.