Quantum Machine Learning, Maria Schuld and Francesco Petruccione, 2021 (Springer)DOI: 10.1007/978-3-030-83057-9 - A comprehensive textbook covering quantum machine learning algorithms, including detailed discussions on feature maps, kernels, and their properties.
Barren plateaus in quantum neural networks, Jarrod R. McClean, Sergio Boixo, Vadim N. Smelyanskiy, Ryan Babbush, and Hartmut Neven, 2018Nature Communications, Vol. 9DOI: 10.1038/s41467-018-07090-4 - This seminal paper identifies the barren plateau phenomenon, which limits the trainability of highly expressive quantum circuits, a critical consideration for feature map design.
PennyLane Documentation: qml.expressibility, Xanadu Quantum Technologies, 2024 - Official documentation for PennyLane's function to quantify the expressibility of quantum circuits, offering practical guidance for empirical evaluation.