2023/08/04 by Valeria Cimini, Mauro Valeri, Simone Piacentini +5 · 27 citations
Computer Science · #Algorithm #Artificial intelligence #Computer science #Curse of dimensionality #Neural Networks and Reservoir Computing #Photonics #Physics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum algorithm #Quantum computer #Quantum mechanics #Robustness (evolution)
paper · pdf · doi:10.1038/s41534-024-00821-0
published in npj Quantum Information 10(1) (Nature Portfolio)
openalex publication_date 2024/02/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/08
Abstract Variational quantum metrology represents a powerful tool to optimize estimation strategies, resulting particularly beneficial for multiparameter estimation problems that often suffer from limitations due to the curse of dimensionality and computational complexity. To overcome these challenges, we develop a variational approach able to efficiently optimize a quantum multiphase sensor. Leveraging the reconfigurability of an integrated photonic device, we implement a hybrid quantum-classical feedback loop able to enhance the estimation performances. The quantum circuit evaluations are used to compute the system partial derivatives by applying the parameter-shift rule, and thus reconstruct experimentally the Fisher information matrix. This in turn is adopted as the cost function of a classical learning algorithm run to optimize the measurement settings. Our experimental results showcase significant improvements in estimation accuracy and noise robustness, highlighting the potential of variational techniques for practical applications in quantum sensing and more generally in quantum information processing using photonic circuits.