Quantum circuits with hierarchical structure have been used to perform binary classification of classical data encoded in a quantum state. We demonstrate that more expressive circuits in the same family achieve better accuracy and can be used to classify highly entangled quantum states, for which there is no known efficient classical method. We compare performance for several different parameterizations on two classical machine learning datasets, Iris and MNIST, and on a synthetic dataset of quantum states. Finally, we demonstrate that performance is robust to noise and deploy an Iris dataset classifier on the ibmqx4 quantum computer.
@article{arxiv.1804.03680,
title = {Hierarchical quantum classifiers},
author = {Edward Grant and Marcello Benedetti and Shuxiang Cao and Andrew Hallam and Joshua Lockhart and Vid Stojevic and Andrew G. Green and Simone Severini},
journal= {arXiv preprint arXiv:1804.03680},
year = {2019}
}