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Quantum Algorithm for Online Exp-concave Optimization
Proceedings of the 41st International Conference on Machine Learning, PMLR 235:17946-17971, 2024.
Abstract
We explore whether quantum advantages can be found for the zeroth-order feedback online exp-concave optimization problem, which is also known as bandit exp-concave optimization with multi-point feedback. We present quantum online quasi-Newton methods to tackle the problem and show that there exists quantum advantages for such problems. Our method approximates the Hessian by quantum estimated inexact gradient and can achieve O(nlogT) regret with O(1) queries at each round, where n is the dimension of the decision set and T is the total decision rounds. Such regret improves the optimal classical algorithm by a factor of T2/3.