Quantum State Readout via Overlap-Based Feature Extraction

TL;DR

This paper introduces a quantum state readout method using overlap-based feature extraction, which efficiently reconstructs quantum states and spectra with fewer measurements than traditional techniques.

Contribution

The paper presents a novel quantum overlap-based fitting approach for quantum state readout and feature extraction, reducing measurement requirements.

Findings

Effective in reconstructing wave functions and spectra from quantum states.

Requires fewer measurements compared to conventional methods.

Preliminary simulations demonstrate promising accuracy.

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 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 continuous function and expressed as a combination of localized functions. The proposed method involves a quantum state readout for both the raw and absolute values of the amplitudes in the quantum state. Preliminary 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 to conventional quantum state measurement techniques.