Quantum state readout via overlap-based feature extraction
Phys. Rev. A 114, 032459 – Published 29 September, 2026
DOI: https://doi.org/10.1103/3l9h-c367
Abstract
In this study, a method for quantum state readout and feature extraction is developed using quantum-overlap-based fitting of function expansions. The approach involves the quantum calculation of quantum overlaps between a target quantum state and a linear combination of nonorthogonal basis functions, such as Lorentzian functions, via measurements, and classical optimization of the parameters in the function expansion. This method is particularly effective in scenarios where the quantum state is approximately represented as a combination of predefined basis functions. The proposed method involves a quantum state readout for both the complex amplitudes and their squared magnitudes (probabilities) in the quantum state. Numerical simulations were performed to reconstruct the grid-based wave function and x-ray absorption spectra from a quantum state, and the results show that our proposed method requires fewer measurements compared with conventional quantum state measurement techniques.
