Quantum advantage without exponential concentration: Trainable kernels for symmetry-structured data

Fuente: arXiv
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Main Authors: Henderson, Laura J., Beer, Kerstin, Karuvade, Salini, Gupta, Riddhi, White, Angela, Shrapnel, Sally
Format: Preprint
Published: 2025
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author Henderson, Laura J.
Beer, Kerstin
Karuvade, Salini
Gupta, Riddhi
White, Angela
Shrapnel, Sally
author_facet Henderson, Laura J.
Beer, Kerstin
Karuvade, Salini
Gupta, Riddhi
White, Angela
Shrapnel, Sally
contents Quantum kernel methods promise enhanced expressivity for learning structured data, but their usefulness has been limited by kernel concentration and barren plateaus. Both effects are mathematically equivalent and suppress trainability. We analytically prove that covariant quantum kernels tailored to datasets with group symmetries avoid exponential concentration, ensuring stable variance and guaranteed trainability independent of system size. Our results extend beyond prior two-coset constructions to arbitrary coset families, broadening the scope of problems where quantum kernels can achieve advantage. We further derive explicit bounds under coherent noise models - including unitary errors in fiducial state preparation, imperfect unitary representations, and perturbations in group element selection - and show through numerical simulations that the kernel variance remains finite and robust, even under substantial noise. These findings establish a family of quantum learning models that are simultaneously trainable, resilient to coherent noise, and linked to classically hard problems, positioning group-symmetric quantum kernels as a promising foundation for near-term and scalable quantum machine learning.
format Preprint
id arxiv_https___arxiv_org_abs_2509_14337
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Quantum advantage without exponential concentration: Trainable kernels for symmetry-structured data
Henderson, Laura J.
Beer, Kerstin
Karuvade, Salini
Gupta, Riddhi
White, Angela
Shrapnel, Sally
Quantum Physics
Data Analysis, Statistics and Probability
Quantum kernel methods promise enhanced expressivity for learning structured data, but their usefulness has been limited by kernel concentration and barren plateaus. Both effects are mathematically equivalent and suppress trainability. We analytically prove that covariant quantum kernels tailored to datasets with group symmetries avoid exponential concentration, ensuring stable variance and guaranteed trainability independent of system size. Our results extend beyond prior two-coset constructions to arbitrary coset families, broadening the scope of problems where quantum kernels can achieve advantage. We further derive explicit bounds under coherent noise models - including unitary errors in fiducial state preparation, imperfect unitary representations, and perturbations in group element selection - and show through numerical simulations that the kernel variance remains finite and robust, even under substantial noise. These findings establish a family of quantum learning models that are simultaneously trainable, resilient to coherent noise, and linked to classically hard problems, positioning group-symmetric quantum kernels as a promising foundation for near-term and scalable quantum machine learning.
title Quantum advantage without exponential concentration: Trainable kernels for symmetry-structured data
topic Quantum Physics
Data Analysis, Statistics and Probability
url https://arxiv.org/abs/2509.14337